Use mcdsl/terminal for all password prompts

Replace direct golang.org/x/term calls with mcdsl/terminal.ReadPassword across mciasctl (6 sites), mciasgrpcctl (1 site), and mciasdb (1 site). Aligns with the new CLI security standard in engineering-standards.md. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-03-28 11:40:11 -07:00
parent e4220b840e
commit 5b5e1a7ed6
142 changed files with 10241 additions and 7788 deletions
@@ -59,7 +59,8 @@ import (
 	"time"

 	"github.com/spf13/cobra"
-	"golang.org/x/term"
+
+	"git.wntrmute.dev/mc/mcdsl/terminal"
 )

 // Global flags bound by the root command's PersistentFlags.
@@ -139,7 +140,7 @@ func authCmd() *cobra.Command {
 // appearing in shell history, ps output, and process argument lists.
 //
 // Security: terminal echo is disabled during password entry
-// (golang.org/x/term.ReadPassword); the raw byte slice is zeroed after use.
+// (mcdsl/terminal.ReadPassword).
 func authLoginCmd() *cobra.Command {
 	var username string
 	var totpCode string
@@ -161,17 +162,10 @@ Example: export MCIAS_TOKEN=$(mciasctl auth login --username alice)`,
 			// Security: always prompt interactively; never accept password as a flag.
 			// This prevents the credential from appearing in shell history, ps output,
 			// and /proc/PID/cmdline.
-			fmt.Fprint(os.Stderr, "Password: ")
-			raw, err := term.ReadPassword(int(os.Stdin.Fd())) //nolint:gosec // uintptr==int on all target platforms
-			fmt.Fprintln(os.Stderr)                           // newline after hidden input
+			passwd, err := terminal.ReadPassword("Password: ")
 			if err != nil {
 				fatalf("read password: %v", err)
 			}
-			passwd := string(raw)
-			// Zero the raw byte slice once copied into the string.
-			for i := range raw {
-				raw[i] = 0
-			}

 			body := map[string]string{
 				"username": username,
@@ -206,10 +200,10 @@ Example: export MCIAS_TOKEN=$(mciasctl auth login --username alice)`,
 // command-line flags to prevent them from appearing in shell history, ps
 // output, and process argument lists.
 //
-// Security: terminal echo is disabled during entry (golang.org/x/term);
-// raw byte slices are zeroed after use.  The server requires the current
-// password to prevent token-theft attacks.  On success all other active
-// sessions are revoked server-side.
+// Security: terminal echo is disabled during entry
+// (mcdsl/terminal.ReadPassword).  The server requires the current password
+// to prevent token-theft attacks.  On success all other active sessions are
+// revoked server-side.
 func authChangePasswordCmd() *cobra.Command {
 	return &cobra.Command{
 		Use:   "change-password",
@@ -221,27 +215,15 @@ Revokes all other active sessions on success.`,
 			c := newController()

 			// Security: always prompt interactively; never accept passwords as flags.
-			fmt.Fprint(os.Stderr, "Current password: ")
-			rawCurrent, err := term.ReadPassword(int(os.Stdin.Fd())) //nolint:gosec // uintptr==int on all target platforms
-			fmt.Fprintln(os.Stderr)
+			currentPasswd, err := terminal.ReadPassword("Current password: ")
 			if err != nil {
 				fatalf("read current password: %v", err)
 			}
-			currentPasswd := string(rawCurrent)
-			for i := range rawCurrent {
-				rawCurrent[i] = 0
-			}

-			fmt.Fprint(os.Stderr, "New password: ")
-			rawNew, err := term.ReadPassword(int(os.Stdin.Fd())) //nolint:gosec // uintptr==int on all target platforms
-			fmt.Fprintln(os.Stderr)
+			newPasswd, err := terminal.ReadPassword("New password: ")
 			if err != nil {
 				fatalf("read new password: %v", err)
 			}
-			newPasswd := string(rawNew)
-			for i := range rawNew {
-				rawNew[i] = 0
-			}

 			body := map[string]string{
 				"current_password": currentPasswd,
@@ -297,20 +279,15 @@ func accountCreateCmd() *cobra.Command {
 			c := newController()

 			// Security: always prompt interactively for human-account passwords; never
-			// accept them as a flag.  Terminal echo is disabled; the raw byte slice is
-			// zeroed after conversion to string.  System accounts have no password.
+			// accept them as a flag.  Terminal echo is disabled via
+			// mcdsl/terminal.ReadPassword.  System accounts have no password.
 			var passwd string
 			if accountType == "human" {
-				fmt.Fprint(os.Stderr, "Password: ")
-				raw, err := term.ReadPassword(int(os.Stdin.Fd())) //nolint:gosec // uintptr==int on all target platforms
-				fmt.Fprintln(os.Stderr)
+				var err error
+				passwd, err = terminal.ReadPassword("Password: ")
 				if err != nil {
 					fatalf("read password: %v", err)
 				}
-				passwd = string(raw)
-				for i := range raw {
-					raw[i] = 0
-				}
 			}

 			body := map[string]string{
@@ -405,7 +382,7 @@ func accountDeleteCmd() *cobra.Command {
 // Security: the new password is always prompted interactively; it is never
 // accepted as a command-line flag to prevent it from appearing in shell
 // history, ps output, and process argument lists.  Terminal echo is disabled
-// (golang.org/x/term); the raw byte slice is zeroed after use.
+// (mcdsl/terminal.ReadPassword).
 func accountSetPasswordCmd() *cobra.Command {
 	var id string

@@ -423,16 +400,10 @@ Revokes all active sessions for the account.`,
 			c := newController()

 			// Security: always prompt interactively; never accept password as a flag.
-			fmt.Fprint(os.Stderr, "New password: ")
-			raw, err := term.ReadPassword(int(os.Stdin.Fd())) //nolint:gosec // uintptr==int on all target platforms
-			fmt.Fprintln(os.Stderr)
+			passwd, err := terminal.ReadPassword("New password: ")
 			if err != nil {
 				fatalf("read password: %v", err)
 			}
-			passwd := string(raw)
-			for i := range raw {
-				raw[i] = 0
-			}

 			body := map[string]string{"new_password": passwd}
 			c.doRequest("PUT", "/v1/accounts/"+id+"/password", body, nil)
@@ -684,20 +655,15 @@ func pgcredsSetCmd() *cobra.Command {

 			// Prompt for the Postgres password interactively if not supplied so it
 			// stays out of shell history.
-			// Security: terminal echo is disabled during entry; the raw byte slice is
-			// zeroed after conversion to string.
+			// Security: terminal echo is disabled during entry via
+			// mcdsl/terminal.ReadPassword.
 			passwd := password
 			if passwd == "" {
-				fmt.Fprint(os.Stderr, "Postgres password: ")
-				raw, err := term.ReadPassword(int(os.Stdin.Fd())) //nolint:gosec // uintptr==int on all target platforms
-				fmt.Fprintln(os.Stderr)
+				var err error
+				passwd, err = terminal.ReadPassword("Postgres password: ")
 				if err != nil {
 					fatalf("read password: %v", err)
 				}
-				passwd = string(raw)
-				for i := range raw {
-					raw[i] = 0
-				}
 			}

 			body := map[string]interface{}{
@@ -8,7 +8,8 @@ import (

 	"git.wntrmute.dev/mc/mcias/internal/auth"
 	"git.wntrmute.dev/mc/mcias/internal/model"
-	"golang.org/x/term"
+
+	"git.wntrmute.dev/mc/mcdsl/terminal"
 )

 func (t *tool) runAccount(args []string) {
@@ -233,20 +234,14 @@ func (t *tool) accountResetTOTP(args []string) {
 // readPassword reads a password from the terminal without echo.
 // Falls back to a regular line read if stdin is not a terminal (e.g. in tests).
 func readPassword(prompt string) (string, error) {
-	fmt.Fprint(os.Stderr, prompt)
-	fd := int(os.Stdin.Fd()) //nolint:gosec // G115: file descriptors are non-negative and fit in int on all supported platforms
-	if term.IsTerminal(fd) {
-		pw, err := term.ReadPassword(fd)
-		fmt.Fprintln(os.Stderr) // newline after hidden input
-		if err != nil {
-			return "", fmt.Errorf("read password from terminal: %w", err)
-		}
-		return string(pw), nil
+	pw, err := terminal.ReadPassword(prompt)
+	if err == nil {
+		return pw, nil
 	}
-	// Not a terminal: read a plain line (for piped input in tests).
+	// Fallback for piped input (e.g. tests).
+	fmt.Fprint(os.Stderr, prompt)
 	var line string
-	_, err := fmt.Fscanln(os.Stdin, &line)
-	if err != nil {
+	if _, err := fmt.Fscanln(os.Stdin, &line); err != nil {
 		return "", fmt.Errorf("read password: %w", err)
 	}
 	return line, nil
@@ -59,11 +59,11 @@ import (
 	"time"

 	"github.com/spf13/cobra"
-	"golang.org/x/term"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/metadata"

+	"git.wntrmute.dev/mc/mcdsl/terminal"
 	mciasv1 "git.wntrmute.dev/mc/mcias/gen/mcias/v1"
 )

@@ -213,7 +213,7 @@ func authCmd(ctl *controller) *cobra.Command {
 // lists.
 //
 // Security: terminal echo is disabled during password entry
-// (golang.org/x/term.ReadPassword); the raw byte slice is zeroed after use.
+// (mcdsl/terminal.ReadPassword).
 func authLoginCmd(ctl *controller) *cobra.Command {
 	var (
 		username string
@@ -230,17 +230,10 @@ func authLoginCmd(ctl *controller) *cobra.Command {
 			// Security: always prompt interactively; never accept password as a flag.
 			// This prevents the credential from appearing in shell history, ps output,
 			// and /proc/PID/cmdline.
-			fmt.Fprint(os.Stderr, "Password: ")
-			raw, err := term.ReadPassword(int(os.Stdin.Fd())) //nolint:gosec // uintptr==int on all target platforms
-			fmt.Fprintln(os.Stderr)
+			passwd, err := terminal.ReadPassword("Password: ")
 			if err != nil {
 				fatalf("read password: %v", err)
 			}
-			passwd := string(raw)
-			// Zero the raw byte slice once copied into the string.
-			for i := range raw {
-				raw[i] = 0
-			}

 			authCl := mciasv1.NewAuthServiceClient(ctl.conn)
 			// Login is a public RPC — no auth context needed.
@@ -3,17 +3,18 @@ module git.wntrmute.dev/mc/mcias
 go 1.26.0

 require (
+	git.wntrmute.dev/mc/mcdsl v1.4.0
 	github.com/go-webauthn/webauthn v0.16.1
 	github.com/golang-jwt/jwt/v5 v5.3.1
 	github.com/golang-migrate/migrate/v4 v4.19.1
 	github.com/google/uuid v1.6.0
-	github.com/pelletier/go-toml/v2 v2.2.4
+	github.com/pelletier/go-toml/v2 v2.3.0
 	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e
+	github.com/spf13/cobra v1.10.2
 	golang.org/x/crypto v0.49.0
-	golang.org/x/term v0.41.0
-	google.golang.org/grpc v1.74.2
-	google.golang.org/protobuf v1.36.7
-	modernc.org/sqlite v1.46.1
+	google.golang.org/grpc v1.79.3
+	google.golang.org/protobuf v1.36.10
+	modernc.org/sqlite v1.47.0
 )

 require (
@@ -26,15 +27,14 @@ require (
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/ncruces/go-strftime v1.0.0 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
-	github.com/spf13/cobra v1.10.2 // indirect
 	github.com/spf13/pflag v1.0.9 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
-	golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 // indirect
 	golang.org/x/net v0.51.0 // indirect
 	golang.org/x/sys v0.42.0 // indirect
+	golang.org/x/term v0.41.0 // indirect
 	golang.org/x/text v0.35.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20250818200422-3122310a409c // indirect
-	modernc.org/libc v1.67.6 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 // indirect
+	modernc.org/libc v1.70.0 // indirect
 	modernc.org/mathutil v1.7.1 // indirect
 	modernc.org/memory v1.11.0 // indirect
 )
@@ -1,3 +1,7 @@
+git.wntrmute.dev/mc/mcdsl v1.4.0 h1:PsEIyskcjBduwHSRwNB/U/uSeU/cv3C8MVr0SRjBRLg=
+git.wntrmute.dev/mc/mcdsl v1.4.0/go.mod h1:MhYahIu7Sg53lE2zpQ20nlrsoNRjQzOJBAlCmom2wJc=
+github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
+github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/cpuguy83/go-md2man/v2 v2.0.6/go.mod h1:oOW0eioCTA6cOiMLiUPZOpcVxMig6NIQQ7OS05n1F4g=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -41,8 +45,8 @@ github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWE
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/ncruces/go-strftime v1.0.0 h1:HMFp8mLCTPp341M/ZnA4qaf7ZlsbTc+miZjCLOFAw7w=
 github.com/ncruces/go-strftime v1.0.0/go.mod h1:Fwc5htZGVVkseilnfgOVb9mKy6w1naJmn9CehxcKcls=
-github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
-github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
+github.com/pelletier/go-toml/v2 v2.3.0 h1:k59bC/lIZREW0/iVaQR8nDHxVq8OVlIzYCOJf421CaM=
+github.com/pelletier/go-toml/v2 v2.3.0/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
@@ -58,25 +62,23 @@ github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 github.com/x448/float16 v0.8.4 h1:qLwI1I70+NjRFUR3zs1JPUCgaCXSh3SW62uAKT1mSBM=
 github.com/x448/float16 v0.8.4/go.mod h1:14CWIYCyZA/cWjXOioeEpHeN/83MdbZDRQHoFcYsOfg=
-go.opentelemetry.io/auto/sdk v1.1.0 h1:cH53jehLUN6UFLY71z+NDOiNJqDdPRaXzTel0sJySYA=
-go.opentelemetry.io/auto/sdk v1.1.0/go.mod h1:3wSPjt5PWp2RhlCcmmOial7AvC4DQqZb7a7wCow3W8A=
-go.opentelemetry.io/otel v1.37.0 h1:9zhNfelUvx0KBfu/gb+ZgeAfAgtWrfHJZcAqFC228wQ=
-go.opentelemetry.io/otel v1.37.0/go.mod h1:ehE/umFRLnuLa/vSccNq9oS1ErUlkkK71gMcN34UG8I=
-go.opentelemetry.io/otel/metric v1.37.0 h1:mvwbQS5m0tbmqML4NqK+e3aDiO02vsf/WgbsdpcPoZE=
-go.opentelemetry.io/otel/metric v1.37.0/go.mod h1:04wGrZurHYKOc+RKeye86GwKiTb9FKm1WHtO+4EVr2E=
-go.opentelemetry.io/otel/sdk v1.36.0 h1:b6SYIuLRs88ztox4EyrvRti80uXIFy+Sqzoh9kFULbs=
-go.opentelemetry.io/otel/sdk v1.36.0/go.mod h1:+lC+mTgD+MUWfjJubi2vvXWcVxyr9rmlshZni72pXeY=
-go.opentelemetry.io/otel/sdk/metric v1.36.0 h1:r0ntwwGosWGaa0CrSt8cuNuTcccMXERFwHX4dThiPis=
-go.opentelemetry.io/otel/sdk/metric v1.36.0/go.mod h1:qTNOhFDfKRwX0yXOqJYegL5WRaW376QbB7P4Pb0qva4=
-go.opentelemetry.io/otel/trace v1.37.0 h1:HLdcFNbRQBE2imdSEgm/kwqmQj1Or1l/7bW6mxVK7z4=
-go.opentelemetry.io/otel/trace v1.37.0/go.mod h1:TlgrlQ+PtQO5XFerSPUYG0JSgGyryXewPGyayAWSBS0=
+go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
+go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
+go.opentelemetry.io/otel v1.39.0 h1:8yPrr/S0ND9QEfTfdP9V+SiwT4E0G7Y5MO7p85nis48=
+go.opentelemetry.io/otel v1.39.0/go.mod h1:kLlFTywNWrFyEdH0oj2xK0bFYZtHRYUdv1NklR/tgc8=
+go.opentelemetry.io/otel/metric v1.39.0 h1:d1UzonvEZriVfpNKEVmHXbdf909uGTOQjA0HF0Ls5Q0=
+go.opentelemetry.io/otel/metric v1.39.0/go.mod h1:jrZSWL33sD7bBxg1xjrqyDjnuzTUB0x1nBERXd7Ftcs=
+go.opentelemetry.io/otel/sdk v1.39.0 h1:nMLYcjVsvdui1B/4FRkwjzoRVsMK8uL/cj0OyhKzt18=
+go.opentelemetry.io/otel/sdk v1.39.0/go.mod h1:vDojkC4/jsTJsE+kh+LXYQlbL8CgrEcwmt1ENZszdJE=
+go.opentelemetry.io/otel/sdk/metric v1.39.0 h1:cXMVVFVgsIf2YL6QkRF4Urbr/aMInf+2WKg+sEJTtB8=
+go.opentelemetry.io/otel/sdk/metric v1.39.0/go.mod h1:xq9HEVH7qeX69/JnwEfp6fVq5wosJsY1mt4lLfYdVew=
+go.opentelemetry.io/otel/trace v1.39.0 h1:2d2vfpEDmCJ5zVYz7ijaJdOF59xLomrvj7bjt6/qCJI=
+go.opentelemetry.io/otel/trace v1.39.0/go.mod h1:88w4/PnZSazkGzz/w84VHpQafiU4EtqqlVdxWy+rNOA=
 go.uber.org/mock v0.6.0 h1:hyF9dfmbgIX5EfOdasqLsWD6xqpNZlXblLB/Dbnwv3Y=
 go.uber.org/mock v0.6.0/go.mod h1:KiVJ4BqZJaMj4svdfmHM0AUx4NJYO8ZNpPnZn1Z+BBU=
 go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
 golang.org/x/crypto v0.49.0 h1:+Ng2ULVvLHnJ/ZFEq4KdcDd/cfjrrjjNSXNzxg0Y4U4=
 golang.org/x/crypto v0.49.0/go.mod h1:ErX4dUh2UM+CFYiXZRTcMpEcN8b/1gxEuv3nODoYtCA=
-golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546 h1:mgKeJMpvi0yx/sU5GsxQ7p6s2wtOnGAHZWCHUM4KGzY=
-golang.org/x/exp v0.0.0-20251023183803-a4bb9ffd2546/go.mod h1:j/pmGrbnkbPtQfxEe5D0VQhZC6qKbfKifgD0oM7sR70=
 golang.org/x/mod v0.33.0 h1:tHFzIWbBifEmbwtGz65eaWyGiGZatSrT9prnU8DbVL8=
 golang.org/x/mod v0.33.0/go.mod h1:swjeQEj+6r7fODbD2cqrnje9PnziFuw4bmLbBZFrQ5w=
 golang.org/x/net v0.51.0 h1:94R/GTO7mt3/4wIKpcR5gkGmRLOuE/2hNGeWq/GBIFo=
@@ -92,29 +94,31 @@ golang.org/x/text v0.35.0 h1:JOVx6vVDFokkpaq1AEptVzLTpDe9KGpj5tR4/X+ybL8=
 golang.org/x/text v0.35.0/go.mod h1:khi/HExzZJ2pGnjenulevKNX1W67CUy0AsXcNubPGCA=
 golang.org/x/tools v0.42.0 h1:uNgphsn75Tdz5Ji2q36v/nsFSfR/9BRFvqhGBaJGd5k=
 golang.org/x/tools v0.42.0/go.mod h1:Ma6lCIwGZvHK6XtgbswSoWroEkhugApmsXyrUmBhfr0=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20250818200422-3122310a409c h1:qXWI/sQtv5UKboZ/zUk7h+mrf/lXORyI+n9DKDAusdg=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20250818200422-3122310a409c/go.mod h1:gw1tLEfykwDz2ET4a12jcXt4couGAm7IwsVaTy0Sflo=
-google.golang.org/grpc v1.74.2 h1:WoosgB65DlWVC9FqI82dGsZhWFNBSLjQ84bjROOpMu4=
-google.golang.org/grpc v1.74.2/go.mod h1:CtQ+BGjaAIXHs/5YS3i473GqwBBa1zGQNevxdeBEXrM=
-google.golang.org/protobuf v1.36.7 h1:IgrO7UwFQGJdRNXH/sQux4R1Dj1WAKcLElzeeRaXV2A=
-google.golang.org/protobuf v1.36.7/go.mod h1:jduwjTPXsFjZGTmRluh+L6NjiWu7pchiJ2/5YcXBHnY=
+gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
+gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217 h1:gRkg/vSppuSQoDjxyiGfN4Upv/h/DQmIR10ZU8dh4Ww=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251202230838-ff82c1b0f217/go.mod h1:7i2o+ce6H/6BluujYR+kqX3GKH+dChPTQU19wjRPiGk=
+google.golang.org/grpc v1.79.3 h1:sybAEdRIEtvcD68Gx7dmnwjZKlyfuc61Dyo9pGXXkKE=
+google.golang.org/grpc v1.79.3/go.mod h1:KmT0Kjez+0dde/v2j9vzwoAScgEPx/Bw1CYChhHLrHQ=
+google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
+google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 modernc.org/cc/v4 v4.27.1 h1:9W30zRlYrefrDV2JE2O8VDtJ1yPGownxciz5rrbQZis=
 modernc.org/cc/v4 v4.27.1/go.mod h1:uVtb5OGqUKpoLWhqwNQo/8LwvoiEBLvZXIQ/SmO6mL0=
-modernc.org/ccgo/v4 v4.30.1 h1:4r4U1J6Fhj98NKfSjnPUN7Ze2c6MnAdL0hWw6+LrJpc=
-modernc.org/ccgo/v4 v4.30.1/go.mod h1:bIOeI1JL54Utlxn+LwrFyjCx2n2RDiYEaJVSrgdrRfM=
-modernc.org/fileutil v1.3.40 h1:ZGMswMNc9JOCrcrakF1HrvmergNLAmxOPjizirpfqBA=
-modernc.org/fileutil v1.3.40/go.mod h1:HxmghZSZVAz/LXcMNwZPA/DRrQZEVP9VX0V4LQGQFOc=
+modernc.org/ccgo/v4 v4.32.0 h1:hjG66bI/kqIPX1b2yT6fr/jt+QedtP2fqojG2VrFuVw=
+modernc.org/ccgo/v4 v4.32.0/go.mod h1:6F08EBCx5uQc38kMGl+0Nm0oWczoo1c7cgpzEry7Uc0=
+modernc.org/fileutil v1.4.0 h1:j6ZzNTftVS054gi281TyLjHPp6CPHr2KCxEXjEbD6SM=
+modernc.org/fileutil v1.4.0/go.mod h1:EqdKFDxiByqxLk8ozOxObDSfcVOv/54xDs/DUHdvCUU=
 modernc.org/gc/v2 v2.6.5 h1:nyqdV8q46KvTpZlsw66kWqwXRHdjIlJOhG6kxiV/9xI=
 modernc.org/gc/v2 v2.6.5/go.mod h1:YgIahr1ypgfe7chRuJi2gD7DBQiKSLMPgBQe9oIiito=
-modernc.org/gc/v3 v3.1.1 h1:k8T3gkXWY9sEiytKhcgyiZ2L0DTyCQ/nvX+LoCljoRE=
-modernc.org/gc/v3 v3.1.1/go.mod h1:HFK/6AGESC7Ex+EZJhJ2Gni6cTaYpSMmU/cT9RmlfYY=
+modernc.org/gc/v3 v3.1.2 h1:ZtDCnhonXSZexk/AYsegNRV1lJGgaNZJuKjJSWKyEqo=
+modernc.org/gc/v3 v3.1.2/go.mod h1:HFK/6AGESC7Ex+EZJhJ2Gni6cTaYpSMmU/cT9RmlfYY=
 modernc.org/goabi0 v0.2.0 h1:HvEowk7LxcPd0eq6mVOAEMai46V+i7Jrj13t4AzuNks=
 modernc.org/goabi0 v0.2.0/go.mod h1:CEFRnnJhKvWT1c1JTI3Avm+tgOWbkOu5oPA8eH8LnMI=
-modernc.org/libc v1.67.6 h1:eVOQvpModVLKOdT+LvBPjdQqfrZq+pC39BygcT+E7OI=
-modernc.org/libc v1.67.6/go.mod h1:JAhxUVlolfYDErnwiqaLvUqc8nfb2r6S6slAgZOnaiE=
+modernc.org/libc v1.70.0 h1:U58NawXqXbgpZ/dcdS9kMshu08aiA6b7gusEusqzNkw=
+modernc.org/libc v1.70.0/go.mod h1:OVmxFGP1CI/Z4L3E0Q3Mf1PDE0BucwMkcXjjLntvHJo=
 modernc.org/mathutil v1.7.1 h1:GCZVGXdaN8gTqB1Mf/usp1Y/hSqgI2vAGGP4jZMCxOU=
 modernc.org/mathutil v1.7.1/go.mod h1:4p5IwJITfppl0G4sUEDtCr4DthTaT47/N3aT6MhfgJg=
 modernc.org/memory v1.11.0 h1:o4QC8aMQzmcwCK3t3Ux/ZHmwFPzE6hf2Y5LbkRs+hbI=
@@ -123,8 +127,8 @@ modernc.org/opt v0.1.4 h1:2kNGMRiUjrp4LcaPuLY2PzUfqM/w9N23quVwhKt5Qm8=
 modernc.org/opt v0.1.4/go.mod h1:03fq9lsNfvkYSfxrfUhZCWPk1lm4cq4N+Bh//bEtgns=
 modernc.org/sortutil v1.2.1 h1:+xyoGf15mM3NMlPDnFqrteY07klSFxLElE2PVuWIJ7w=
 modernc.org/sortutil v1.2.1/go.mod h1:7ZI3a3REbai7gzCLcotuw9AC4VZVpYMjDzETGsSMqJE=
-modernc.org/sqlite v1.46.1 h1:eFJ2ShBLIEnUWlLy12raN0Z1plqmFX9Qe3rjQTKt6sU=
-modernc.org/sqlite v1.46.1/go.mod h1:CzbrU2lSB1DKUusvwGz7rqEKIq+NUd8GWuBBZDs9/nA=
+modernc.org/sqlite v1.47.0 h1:R1XyaNpoW4Et9yly+I2EeX7pBza/w+pmYee/0HJDyKk=
+modernc.org/sqlite v1.47.0/go.mod h1:hWjRO6Tj/5Ik8ieqxQybiEOUXy0NJFNp2tpvVpKlvig=
 modernc.org/strutil v1.2.1 h1:UneZBkQA+DX2Rp35KcM69cSsNES9ly8mQWD71HKlOA0=
 modernc.org/strutil v1.2.1/go.mod h1:EHkiggD70koQxjVdSBM3JKM7k6L0FbGE5eymy9i3B9A=
 modernc.org/token v1.1.0 h1:Xl7Ap9dKaEs5kLoOQeQmPWevfnk/DM5qcLcYlA8ys6Y=
@@ -0,0 +1,36 @@
+// Package terminal provides secure terminal input helpers for CLI tools.
+package terminal
+
+import (
+	"fmt"
+	"os"
+
+	"golang.org/x/term"
+)
+
+// ReadPassword prints the given prompt to stderr and reads a password
+// from the terminal with echo disabled. It prints a newline after the
+// input is complete so the cursor advances normally.
+func ReadPassword(prompt string) (string, error) {
+	b, err := readRaw(prompt)
+	if err != nil {
+		return "", err
+	}
+	return string(b), nil
+}
+
+// ReadPasswordBytes is like ReadPassword but returns a []byte so the
+// caller can zeroize the buffer after use.
+func ReadPasswordBytes(prompt string) ([]byte, error) {
+	return readRaw(prompt)
+}
+
+func readRaw(prompt string) ([]byte, error) {
+	fmt.Fprint(os.Stderr, prompt)
+	b, err := term.ReadPassword(int(os.Stdin.Fd())) //nolint:gosec // fd fits in int
+	fmt.Fprintln(os.Stderr)
+	if err != nil {
+		return nil, err
+	}
+	return b, nil
+}
@@ -5,3 +5,4 @@ cmd/tomljson/tomljson
 cmd/tomltestgen/tomltestgen
 dist
 tests/
+test-results
@@ -1,84 +1,76 @@
-[service]
-golangci-lint-version =  "1.39.0"
-
-[linters-settings.wsl]
-allow-assign-and-anything = true
-
-[linters-settings.exhaustive]
-default-signifies-exhaustive = true
+version = "2"

 [linters]
-disable-all = true
+default = "none"
 enable = [
    "asciicheck",
    "bodyclose",
-    "cyclop",
-    "deadcode",
-    "depguard",
    "dogsled",
    "dupl",
    "durationcheck",
    "errcheck",
    "errorlint",
    "exhaustive",
-    # "exhaustivestruct",
-    "exportloopref",
    "forbidigo",
-    # "forcetypeassert",
-    "funlen",
-    "gci",
-    # "gochecknoglobals",
    "gochecknoinits",
-    "gocognit",
    "goconst",
    "gocritic",
-    "gocyclo",
-    "godot",
-    "godox",
-    # "goerr113",
-    "gofmt",
-    "gofumpt",
+    "godoclint",
    "goheader",
-    "goimports",
-    "golint",
-    "gomnd",
-    # "gomoddirectives",
    "gomodguard",
    "goprintffuncname",
    "gosec",
-    "gosimple",
    "govet",
-    # "ifshort",
    "importas",
    "ineffassign",
    "lll",
    "makezero",
+    "mirror",
    "misspell",
    "nakedret",
-    "nestif",
    "nilerr",
-    # "nlreturn",
    "noctx",
    "nolintlint",
-    #"paralleltest",
+    "perfsprint",
    "prealloc",
    "predeclared",
    "revive",
    "rowserrcheck",
    "sqlclosecheck",
    "staticcheck",
-    "structcheck",
-    "stylecheck",
-    # "testpackage",
    "thelper",
    "tparallel",
-    "typecheck",
    "unconvert",
    "unparam",
    "unused",
-    "varcheck",
+    "usetesting",
    "wastedassign",
    "whitespace",
-    # "wrapcheck",
-    # "wsl"
+]
+
+[linters.settings.exhaustive]
+default-signifies-exhaustive = true
+
+[linters.settings.lll]
+line-length = 150
+
+[[linters.exclusions.rules]]
+path = ".test.go"
+linters = ["goconst", "gosec"]
+
+[[linters.exclusions.rules]]
+path = "main.go"
+linters = ["forbidigo"]
+
+[[linters.exclusions.rules]]
+path = "internal"
+linters = ["revive"]
+text = "(exported|indent-error-flow): "
+
+[formatters]
+enable = [
+    "gci",
+    "gofmt",
+    "gofumpt",
+    "goimports",
 ]
@@ -22,7 +22,6 @@ builds:
      - linux_riscv64
      - windows_amd64
      - windows_arm64
-      - windows_arm
      - darwin_amd64
      - darwin_arm64
  - id: tomljson
@@ -42,7 +41,6 @@ builds:
      - linux_riscv64
      - windows_amd64
      - windows_arm64
-      - windows_arm
      - darwin_amd64
      - darwin_arm64
  - id: jsontoml
@@ -62,7 +60,6 @@ builds:
      - linux_arm
      - windows_amd64
      - windows_arm64
-      - windows_arm
      - darwin_amd64
      - darwin_arm64
 universal_binaries:
@@ -0,0 +1,64 @@
+# Agent Guidelines for go-toml
+
+This file provides guidelines for AI agents contributing to go-toml. All agents must follow these rules derived from [CONTRIBUTING.md](./CONTRIBUTING.md).
+
+## Project Overview
+
+go-toml is a TOML library for Go. The goal is to provide an easy-to-use and efficient TOML implementation that gets the job done without getting in the way.
+
+## Code Change Rules
+
+### Backward Compatibility
+
+- **No backward-incompatible changes** unless explicitly discussed and approved
+- Avoid breaking people's programs unless absolutely necessary
+
+### Testing Requirements
+
+- **All bug fixes must include regression tests**
+- **All new code must be tested**
+- Run tests before submitting: `go test -race ./...`
+- Test coverage must not decrease. Check with:
+  ```bash
+  go test -covermode=atomic -coverprofile=coverage.out
+  go tool cover -func=coverage.out
+  ```
+- All lines of code touched by changes should be covered by tests
+
+### Performance Requirements
+
+- go-toml aims to stay efficient; avoid performance regressions
+- Run benchmarks to verify: `go test ./... -bench=. -count=10`
+- Compare results using [benchstat](https://pkg.go.dev/golang.org/x/perf/cmd/benchstat)
+
+### Documentation
+
+- New features or feature extensions must include documentation
+- Documentation lives in [README.md](./README.md) and throughout source code
+
+### Code Style
+
+- Follow existing code format and structure
+- Code must pass `go fmt`
+- Code must pass linting with the same golangci-lint version as CI (see version in `.github/workflows/lint.yml`):
+  ```bash
+  # Install specific version (check lint.yml for current version)
+  curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/HEAD/install.sh | sh -s -- -b $(go env GOPATH)/bin <version>
+  # Run linter
+  golangci-lint run ./...
+  ```
+
+### Commit Messages
+
+- Commit messages must explain **why** the change is needed
+- Keep messages clear and informative even if details are in the PR description
+
+## Pull Request Checklist
+
+Before submitting:
+
+1. Tests pass (`go test -race ./...`)
+2. No backward-incompatible changes (unless discussed)
+3. Relevant documentation added/updated
+4. No performance regression (verify with benchmarks)
+5. Title is clear and understandable for changelog
@@ -33,7 +33,7 @@ The documentation is present in the [README][readme] and thorough the source
 code. On release, it gets updated on [pkg.go.dev][pkg.go.dev]. To make a change
 to the documentation, create a pull request with your proposed changes. For
 simple changes like that, the easiest way to go is probably the "Fork this
-project and edit the file" button on Github, displayed at the top right of the
+project and edit the file" button on GitHub, displayed at the top right of the
 file. Unless it's a trivial change (for example a typo), provide a little bit of
 context in your pull request description or commit message.

@@ -92,6 +92,48 @@ However, given GitHub's new policy to _not_ run Actions on pull requests until a
 maintainer clicks on button, it is highly recommended that you run them locally
 as you make changes.

+### Test across Go versions
+
+The repository includes tooling to test go-toml across multiple Go versions
+(1.11 through 1.25) both locally and in GitHub Actions.
+
+#### Local testing with Docker
+
+Prerequisites: Docker installed and running, Bash shell, `rsync` command.
+
+```bash
+# Test all Go versions in parallel (default)
+./test-go-versions.sh
+
+# Test specific versions
+./test-go-versions.sh 1.21 1.22 1.23
+
+# Test sequentially (slower but uses less resources)
+./test-go-versions.sh --sequential
+
+# Verbose output with custom results directory
+./test-go-versions.sh --verbose --output ./my-results 1.24 1.25
+
+# Show all options
+./test-go-versions.sh --help
+```
+
+The script creates Docker containers for each Go version and runs the full test
+suite. Results are saved to a `test-results/` directory with individual logs and
+a comprehensive summary report.
+
+The script only exits with a non-zero status code if either of the two most
+recent Go versions fail.
+
+#### GitHub Actions testing (maintainers)
+
+1. Go to the **Actions** tab in the GitHub repository
+2. Select **"Go Versions Compatibility Test"** from the workflow list
+3. Click **"Run workflow"**
+4. Optionally customize:
+   - **Go versions**: Space-separated list (e.g., `1.21 1.22 1.23`)
+   - **Execution mode**: Parallel (faster) or sequential (more stable)
+
 ### Check coverage

 We use `go tool cover` to compute test coverage. Most code editors have a way to
@@ -111,7 +153,7 @@ code lowers the coverage.

 Go-toml aims to stay efficient. We rely on a set of scenarios executed with Go's
 builtin benchmark systems. Because of their noisy nature, containers provided by
-Github Actions cannot be reliably used for benchmarking. As a result, you are
+GitHub Actions cannot be reliably used for benchmarking. As a result, you are
 responsible for checking that your changes do not incur a performance penalty.
 You can run their following to execute benchmarks:

@@ -168,13 +210,13 @@ Checklist:
 1. Decide on the next version number. Use semver. Review commits since last
   version to assess.
 2. Tag release. For example:
-```
-git checkout v2
-git pull
-git tag v2.2.0
-git push --tags
-```
-3. CI automatically builds a draft Github release. Review it and edit as
+   ```
+   git checkout v2
+   git pull
+   git tag v2.2.0
+   git push --tags
+   ```
+3. CI automatically builds a draft GitHub release. Review it and edit as
   necessary. Look for "Other changes". That would indicate a pull request not
   labeled properly. Tweak labels and pull request titles until changelog looks
   good for users.
@@ -107,7 +107,11 @@ type MyConfig struct {
 ### Unmarshaling

 [`Unmarshal`][unmarshal] reads a TOML document and fills a Go structure with its
-content. For example:
+content. 
+
+Note that the struct variable names are _capitalized_, while the variables in the toml document are _lowercase_.
+
+For example:

 ```go
 doc := `
@@ -133,6 +137,62 @@ fmt.Println("tags:", cfg.Tags)

 [unmarshal]: https://pkg.go.dev/github.com/pelletier/go-toml/v2#Unmarshal

+
+Here is an example using tables with some simple nesting:
+
+```go
+doc := `
+age = 45
+fruits = ["apple", "pear"]
+
+# these are very important!
+[my-variables]
+first = 1
+second = 0.2
+third = "abc"
+
+# this is not so important.
+[my-variables.b]
+bfirst = 123
+`
+
+var Document struct {
+	Age int
+	Fruits []string
+
+	Myvariables struct {
+		First  int
+		Second float64
+		Third  string
+
+		B struct {
+			Bfirst int
+		}
+	} `toml:"my-variables"`
+}
+
+err := toml.Unmarshal([]byte(doc), &Document)
+if err != nil {
+	panic(err)
+}
+
+fmt.Println("age:", Document.Age)
+fmt.Println("fruits:", Document.Fruits)
+fmt.Println("my-variables.first:", Document.Myvariables.First)
+fmt.Println("my-variables.second:", Document.Myvariables.Second)
+fmt.Println("my-variables.third:", Document.Myvariables.Third)
+fmt.Println("my-variables.B.Bfirst:", Document.Myvariables.B.Bfirst)
+
+// Output:
+// age: 45
+// fruits: [apple pear]
+// my-variables.first: 1
+// my-variables.second: 0.2
+// my-variables.third: abc
+// my-variables.B.Bfirst: 123
+```
+
+
 ### Marshaling

 [`Marshal`][marshal] is the opposite of Unmarshal: it represents a Go structure
@@ -175,17 +235,17 @@ the AST level. See https://pkg.go.dev/github.com/pelletier/go-toml/v2/unstable.
 Execution time speedup compared to other Go TOML libraries:

 <table>
-	<thead>
-		<tr><th>Benchmark</th><th>go-toml v1</th><th>BurntSushi/toml</th></tr>
-	</thead>
-	<tbody>
-		<tr><td>Marshal/HugoFrontMatter-2</td><td>1.9x</td><td>2.2x</td></tr>
-		<tr><td>Marshal/ReferenceFile/map-2</td><td>1.7x</td><td>2.1x</td></tr>
-		<tr><td>Marshal/ReferenceFile/struct-2</td><td>2.2x</td><td>3.0x</td></tr>
-		<tr><td>Unmarshal/HugoFrontMatter-2</td><td>2.9x</td><td>2.7x</td></tr>
-		<tr><td>Unmarshal/ReferenceFile/map-2</td><td>2.6x</td><td>2.7x</td></tr>
-		<tr><td>Unmarshal/ReferenceFile/struct-2</td><td>4.6x</td><td>5.1x</td></tr>
-	 </tbody>
+    <thead>
+        <tr><th>Benchmark</th><th>go-toml v1</th><th>BurntSushi/toml</th></tr>
+    </thead>
+    <tbody>
+        <tr><td>Marshal/HugoFrontMatter-2</td><td>2.1x</td><td>2.0x</td></tr>
+        <tr><td>Marshal/ReferenceFile/map-2</td><td>2.0x</td><td>2.0x</td></tr>
+        <tr><td>Marshal/ReferenceFile/struct-2</td><td>2.3x</td><td>2.5x</td></tr>
+        <tr><td>Unmarshal/HugoFrontMatter-2</td><td>3.3x</td><td>2.8x</td></tr>
+        <tr><td>Unmarshal/ReferenceFile/map-2</td><td>2.9x</td><td>3.0x</td></tr>
+        <tr><td>Unmarshal/ReferenceFile/struct-2</td><td>4.8x</td><td>5.0x</td></tr>
+     </tbody>
 </table>
 <details><summary>See more</summary>
 <p>The table above has the results of the most common use-cases. The table below
@@ -193,22 +253,22 @@ contains the results of all benchmarks, including unrealistic ones. It is
 provided for completeness.</p>

 <table>
-	<thead>
-		<tr><th>Benchmark</th><th>go-toml v1</th><th>BurntSushi/toml</th></tr>
-	</thead>
-	<tbody>
-		<tr><td>Marshal/SimpleDocument/map-2</td><td>1.8x</td><td>2.7x</td></tr>
-		<tr><td>Marshal/SimpleDocument/struct-2</td><td>2.7x</td><td>3.8x</td></tr>
-		<tr><td>Unmarshal/SimpleDocument/map-2</td><td>3.8x</td><td>3.0x</td></tr>
-		<tr><td>Unmarshal/SimpleDocument/struct-2</td><td>5.6x</td><td>4.1x</td></tr>
-		<tr><td>UnmarshalDataset/example-2</td><td>3.0x</td><td>3.2x</td></tr>
-		<tr><td>UnmarshalDataset/code-2</td><td>2.3x</td><td>2.9x</td></tr>
-		<tr><td>UnmarshalDataset/twitter-2</td><td>2.6x</td><td>2.7x</td></tr>
-		<tr><td>UnmarshalDataset/citm_catalog-2</td><td>2.2x</td><td>2.3x</td></tr>
-		<tr><td>UnmarshalDataset/canada-2</td><td>1.8x</td><td>1.5x</td></tr>
-		<tr><td>UnmarshalDataset/config-2</td><td>4.1x</td><td>2.9x</td></tr>
-		<tr><td>geomean</td><td>2.7x</td><td>2.8x</td></tr>
-	 </tbody>
+    <thead>
+        <tr><th>Benchmark</th><th>go-toml v1</th><th>BurntSushi/toml</th></tr>
+    </thead>
+    <tbody>
+        <tr><td>Marshal/SimpleDocument/map-2</td><td>2.0x</td><td>2.9x</td></tr>
+        <tr><td>Marshal/SimpleDocument/struct-2</td><td>2.5x</td><td>3.6x</td></tr>
+        <tr><td>Unmarshal/SimpleDocument/map-2</td><td>4.2x</td><td>3.4x</td></tr>
+        <tr><td>Unmarshal/SimpleDocument/struct-2</td><td>5.9x</td><td>4.4x</td></tr>
+        <tr><td>UnmarshalDataset/example-2</td><td>3.2x</td><td>2.9x</td></tr>
+        <tr><td>UnmarshalDataset/code-2</td><td>2.4x</td><td>2.8x</td></tr>
+        <tr><td>UnmarshalDataset/twitter-2</td><td>2.7x</td><td>2.5x</td></tr>
+        <tr><td>UnmarshalDataset/citm_catalog-2</td><td>2.3x</td><td>2.3x</td></tr>
+        <tr><td>UnmarshalDataset/canada-2</td><td>1.9x</td><td>1.5x</td></tr>
+        <tr><td>UnmarshalDataset/config-2</td><td>5.4x</td><td>3.0x</td></tr>
+        <tr><td>geomean</td><td>2.9x</td><td>2.8x</td></tr>
+     </tbody>
 </table>
 <p>This table can be generated with <code>./ci.sh benchmark -a -html</code>.</p>
 </details>
@@ -147,7 +147,7 @@ bench() {
    pushd "$dir"

    if [ "${replace}" != "" ]; then
-        find ./benchmark/ -iname '*.go' -exec sed -i -E "s|github.com/pelletier/go-toml/v2|${replace}|g" {} \;
+        find ./benchmark/ -iname '*.go' -exec sed -i -E "s|github.com/pelletier/go-toml/v2\"|${replace}\"|g" {} \;
        go get "${replace}"
    fi

@@ -195,6 +195,11 @@ for line in reversed(lines[2:]):
        "%.1fx" % (float(line[3])/v2),  # v1
        "%.1fx" % (float(line[7])/v2),  # bs
    ])
+
+if not results:
+    print("No benchmark results to display.", file=sys.stderr)
+    sys.exit(1)
+
 # move geomean to the end
 results.append(results[0])
 del results[0]
@@ -230,8 +230,8 @@ func parseLocalTime(b []byte) (LocalTime, []byte, error) {
 		return t, nil, err
 	}

-	if t.Second > 60 {
-		return t, nil, unstable.NewParserError(b[6:8], "seconds cannot be greater 60")
+	if t.Second > 59 {
+		return t, nil, unstable.NewParserError(b[6:8], "seconds cannot be greater than 59")
 	}

 	b = b[8:]
@@ -279,7 +279,6 @@ func parseLocalTime(b []byte) (LocalTime, []byte, error) {
 	return t, b, nil
 }

-//nolint:cyclop
 func parseFloat(b []byte) (float64, error) {
 	if len(b) == 4 && (b[0] == '+' || b[0] == '-') && b[1] == 'n' && b[2] == 'a' && b[3] == 'n' {
 		return math.NaN(), nil
@@ -2,10 +2,10 @@ package toml

 import (
 	"fmt"
+	"reflect"
 	"strconv"
 	"strings"

-	"github.com/pelletier/go-toml/v2/internal/danger"
 	"github.com/pelletier/go-toml/v2/unstable"
 )

@@ -54,6 +54,18 @@ func (s *StrictMissingError) String() string {
 	return buf.String()
 }

+// Unwrap returns wrapped decode errors
+//
+// Implements errors.Join() interface.
+func (s *StrictMissingError) Unwrap() []error {
+	errs := make([]error, len(s.Errors))
+	for i := range s.Errors {
+		errs[i] = &s.Errors[i]
+	}
+	return errs
+}
+
+// Key represents a TOML key as a sequence of key parts.
 type Key []string

 // Error returns the error message contained in the DecodeError.
@@ -78,7 +90,7 @@ func (e *DecodeError) Key() Key {
 	return e.key
 }

-// decodeErrorFromHighlight creates a DecodeError referencing a highlighted
+// wrapDecodeError creates a DecodeError referencing a highlighted
 // range of bytes from document.
 //
 // highlight needs to be a sub-slice of document, or this function panics.
@@ -88,7 +100,7 @@ func (e *DecodeError) Key() Key {
 //
 //nolint:funlen
 func wrapDecodeError(document []byte, de *unstable.ParserError) *DecodeError {
-	offset := danger.SubsliceOffset(document, de.Highlight)
+	offset := subsliceOffset(document, de.Highlight)

 	errMessage := de.Error()
 	errLine, errColumn := positionAtEnd(document[:offset])
@@ -248,5 +260,24 @@ func positionAtEnd(b []byte) (row int, column int) {
 		}
 	}

-	return
+	return row, column
+}
+
+// subsliceOffset returns the byte offset of subslice within data.
+// subslice must share the same backing array as data.
+func subsliceOffset(data []byte, subslice []byte) int {
+	if len(subslice) == 0 {
+		return 0
+	}
+
+	// Use reflect to get the data pointers of both slices.
+	// This is safe because we're only reading the pointer values for comparison.
+	dataPtr := reflect.ValueOf(data).Pointer()
+	subPtr := reflect.ValueOf(subslice).Pointer()
+
+	offset := int(subPtr - dataPtr)
+	if offset < 0 || offset > len(data) {
+		panic("subslice is not within data")
+	}
+	return offset
 }
@@ -1,6 +1,6 @@
 package characters

-var invalidAsciiTable = [256]bool{
+var invalidASCIITable = [256]bool{
 	0x00: true,
 	0x01: true,
 	0x02: true,
@@ -37,6 +37,6 @@ var invalidAsciiTable = [256]bool{
 	0x7F: true,
 }

-func InvalidAscii(b byte) bool {
-	return invalidAsciiTable[b]
+func InvalidASCII(b byte) bool {
+	return invalidASCIITable[b]
 }
@@ -1,20 +1,12 @@
+// Package characters provides functions for working with string encodings.
 package characters

 import (
 	"unicode/utf8"
 )

-type utf8Err struct {
-	Index int
-	Size  int
-}
-
-func (u utf8Err) Zero() bool {
-	return u.Size == 0
-}
-
-// Verified that a given string is only made of valid UTF-8 characters allowed
-// by the TOML spec:
+// Utf8TomlValidAlreadyEscaped verifies that a given string is only made of
+// valid UTF-8 characters allowed by the TOML spec:
 //
 // Any Unicode character may be used except those that must be escaped:
 // quotation mark, backslash, and the control characters other than tab (U+0000
@@ -23,8 +15,8 @@ func (u utf8Err) Zero() bool {
 // It is a copy of the Go 1.17 utf8.Valid implementation, tweaked to exit early
 // when a character is not allowed.
 //
-// The returned utf8Err is Zero() if the string is valid, or contains the byte
-// index and size of the invalid character.
+// The returned slice is empty if the string is valid, or contains the bytes
+// of the invalid character.
 //
 // quotation mark => already checked
 // backslash => already checked
@@ -32,9 +24,8 @@ func (u utf8Err) Zero() bool {
 // 0x9 => tab, ok
 // 0xA - 0x1F => invalid
 // 0x7F => invalid
-func Utf8TomlValidAlreadyEscaped(p []byte) (err utf8Err) {
+func Utf8TomlValidAlreadyEscaped(p []byte) []byte {
 	// Fast path. Check for and skip 8 bytes of ASCII characters per iteration.
-	offset := 0
 	for len(p) >= 8 {
 		// Combining two 32 bit loads allows the same code to be used
 		// for 32 and 64 bit platforms.
@@ -48,24 +39,19 @@ func Utf8TomlValidAlreadyEscaped(p []byte) (err utf8Err) {
 		}

 		for i, b := range p[:8] {
-			if InvalidAscii(b) {
-				err.Index = offset + i
-				err.Size = 1
-				return
+			if InvalidASCII(b) {
+				return p[i : i+1]
 			}
 		}

 		p = p[8:]
-		offset += 8
 	}
 	n := len(p)
 	for i := 0; i < n; {
 		pi := p[i]
 		if pi < utf8.RuneSelf {
-			if InvalidAscii(pi) {
-				err.Index = offset + i
-				err.Size = 1
-				return
+			if InvalidASCII(pi) {
+				return p[i : i+1]
 			}
 			i++
 			continue
@@ -73,44 +59,34 @@ func Utf8TomlValidAlreadyEscaped(p []byte) (err utf8Err) {
 		x := first[pi]
 		if x == xx {
 			// Illegal starter byte.
-			err.Index = offset + i
-			err.Size = 1
-			return
+			return p[i : i+1]
 		}
 		size := int(x & 7)
 		if i+size > n {
 			// Short or invalid.
-			err.Index = offset + i
-			err.Size = n - i
-			return
+			return p[i:n]
 		}
 		accept := acceptRanges[x>>4]
 		if c := p[i+1]; c < accept.lo || accept.hi < c {
-			err.Index = offset + i
-			err.Size = 2
-			return
-		} else if size == 2 {
+			return p[i : i+2]
+		} else if size == 2 { //revive:disable:empty-block
 		} else if c := p[i+2]; c < locb || hicb < c {
-			err.Index = offset + i
-			err.Size = 3
-			return
-		} else if size == 3 {
+			return p[i : i+3]
+		} else if size == 3 { //revive:disable:empty-block
 		} else if c := p[i+3]; c < locb || hicb < c {
-			err.Index = offset + i
-			err.Size = 4
-			return
+			return p[i : i+4]
 		}
 		i += size
 	}
-	return
+	return nil
 }

-// Return the size of the next rune if valid, 0 otherwise.
+// Utf8ValidNext returns the size of the next rune if valid, 0 otherwise.
 func Utf8ValidNext(p []byte) int {
 	c := p[0]

 	if c < utf8.RuneSelf {
-		if InvalidAscii(c) {
+		if InvalidASCII(c) {
 			return 0
 		}
 		return 1
@@ -129,10 +105,10 @@ func Utf8ValidNext(p []byte) int {
 	accept := acceptRanges[x>>4]
 	if c := p[1]; c < accept.lo || accept.hi < c {
 		return 0
-	} else if size == 2 {
+	} else if size == 2 { //nolint:revive
 	} else if c := p[2]; c < locb || hicb < c {
 		return 0
-	} else if size == 3 {
+	} else if size == 3 { //nolint:revive
 	} else if c := p[3]; c < locb || hicb < c {
 		return 0
 	}
@@ -1,65 +0,0 @@
-package danger
-
-import (
-	"fmt"
-	"reflect"
-	"unsafe"
-)
-
-const maxInt = uintptr(int(^uint(0) >> 1))
-
-func SubsliceOffset(data []byte, subslice []byte) int {
-	datap := (*reflect.SliceHeader)(unsafe.Pointer(&data))
-	hlp := (*reflect.SliceHeader)(unsafe.Pointer(&subslice))
-
-	if hlp.Data < datap.Data {
-		panic(fmt.Errorf("subslice address (%d) is before data address (%d)", hlp.Data, datap.Data))
-	}
-	offset := hlp.Data - datap.Data
-
-	if offset > maxInt {
-		panic(fmt.Errorf("slice offset larger than int (%d)", offset))
-	}
-
-	intoffset := int(offset)
-
-	if intoffset > datap.Len {
-		panic(fmt.Errorf("slice offset (%d) is farther than data length (%d)", intoffset, datap.Len))
-	}
-
-	if intoffset+hlp.Len > datap.Len {
-		panic(fmt.Errorf("slice ends (%d+%d) is farther than data length (%d)", intoffset, hlp.Len, datap.Len))
-	}
-
-	return intoffset
-}
-
-func BytesRange(start []byte, end []byte) []byte {
-	if start == nil || end == nil {
-		panic("cannot call BytesRange with nil")
-	}
-	startp := (*reflect.SliceHeader)(unsafe.Pointer(&start))
-	endp := (*reflect.SliceHeader)(unsafe.Pointer(&end))
-
-	if startp.Data > endp.Data {
-		panic(fmt.Errorf("start pointer address (%d) is after end pointer address (%d)", startp.Data, endp.Data))
-	}
-
-	l := startp.Len
-	endLen := int(endp.Data-startp.Data) + endp.Len
-	if endLen > l {
-		l = endLen
-	}
-
-	if l > startp.Cap {
-		panic(fmt.Errorf("range length is larger than capacity"))
-	}
-
-	return start[:l]
-}
-
-func Stride(ptr unsafe.Pointer, size uintptr, offset int) unsafe.Pointer {
-	// TODO: replace with unsafe.Add when Go 1.17 is released
-	//   https://github.com/golang/go/issues/40481
-	return unsafe.Pointer(uintptr(ptr) + uintptr(int(size)*offset))
-}
@@ -1,23 +0,0 @@
-package danger
-
-import (
-	"reflect"
-	"unsafe"
-)
-
-// typeID is used as key in encoder and decoder caches to enable using
-// the optimize runtime.mapaccess2_fast64 function instead of the more
-// expensive lookup if we were to use reflect.Type as map key.
-//
-// typeID holds the pointer to the reflect.Type value, which is unique
-// in the program.
-//
-// https://github.com/segmentio/encoding/blob/master/json/codec.go#L59-L61
-type TypeID unsafe.Pointer
-
-func MakeTypeID(t reflect.Type) TypeID {
-	// reflect.Type has the fields:
-	// typ unsafe.Pointer
-	// ptr unsafe.Pointer
-	return TypeID((*[2]unsafe.Pointer)(unsafe.Pointer(&t))[1])
-}
@@ -36,7 +36,7 @@ func (t *KeyTracker) Pop(node *unstable.Node) {
 	}
 }

-// Key returns the current key
+// Key returns the current key.
 func (t *KeyTracker) Key() []string {
 	k := make([]string, len(t.k))
 	copy(k, t.k)
@@ -288,11 +288,12 @@ func (s *SeenTracker) checkKeyValue(node *unstable.Node) (bool, error) {
 			idx = s.create(parentIdx, k, tableKind, false, true)
 		} else {
 			entry := s.entries[idx]
-			if it.IsLast() {
+			switch {
+			case it.IsLast():
 				return false, fmt.Errorf("toml: key %s is already defined", string(k))
-			} else if entry.kind != tableKind {
+			case entry.kind != tableKind:
 				return false, fmt.Errorf("toml: expected %s to be a table, not a %s", string(k), entry.kind)
-			} else if entry.explicit {
+			case entry.explicit:
 				return false, fmt.Errorf("toml: cannot redefine table %s that has already been explicitly defined", string(k))
 			}
 		}
@@ -309,16 +310,16 @@ func (s *SeenTracker) checkKeyValue(node *unstable.Node) (bool, error) {
 		return s.checkInlineTable(value)
 	case unstable.Array:
 		return s.checkArray(value)
+	default:
+		return false, nil
 	}
-
-	return false, nil
 }

 func (s *SeenTracker) checkArray(node *unstable.Node) (first bool, err error) {
 	it := node.Children()
 	for it.Next() {
 		n := it.Node()
-		switch n.Kind {
+		switch n.Kind { //nolint:exhaustive
 		case unstable.InlineTable:
 			first, err = s.checkInlineTable(n)
 			if err != nil {
@@ -1 +1,2 @@
+// Package tracker provides functions for keeping track of AST nodes.
 package tracker
@@ -45,7 +45,7 @@ func (d *LocalDate) UnmarshalText(b []byte) error {
 type LocalTime struct {
 	Hour       int // Hour of the day: [0; 24[
 	Minute     int // Minute of the hour: [0; 60[
-	Second     int // Second of the minute: [0; 60[
+	Second     int // Second of the minute: [0; 59]
 	Nanosecond int // Nanoseconds within the second:  [0, 1000000000[
 	Precision  int // Number of digits to display for Nanosecond.
 }
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"math"
@@ -42,7 +43,7 @@ type Encoder struct {
 	arraysMultiline    bool
 	indentSymbol       string
 	indentTables       bool
-	marshalJsonNumbers bool
+	marshalJSONNumbers bool
 }

 // NewEncoder returns a new Encoder that writes to w.
@@ -89,14 +90,14 @@ func (enc *Encoder) SetIndentTables(indent bool) *Encoder {
 	return enc
 }

-// SetMarshalJsonNumbers forces the encoder to serialize `json.Number` as a
+// SetMarshalJSONNumbers forces the encoder to serialize `json.Number` as a
 // float or integer instead of relying on TextMarshaler to emit a string.
 //
 // *Unstable:* This method does not follow the compatibility guarantees of
 // semver. It can be changed or removed without a new major version being
 // issued.
-func (enc *Encoder) SetMarshalJsonNumbers(indent bool) *Encoder {
-	enc.marshalJsonNumbers = indent
+func (enc *Encoder) SetMarshalJSONNumbers(indent bool) *Encoder {
+	enc.marshalJSONNumbers = indent
 	return enc
 }

@@ -161,6 +162,8 @@ func (enc *Encoder) SetMarshalJsonNumbers(indent bool) *Encoder {
 //
 // The "omitempty" option prevents empty values or groups from being emitted.
 //
+// The "omitzero" option prevents zero values or groups from being emitted.
+//
 // The "commented" option prefixes the value and all its children with a comment
 // symbol.
 //
@@ -177,7 +180,7 @@ func (enc *Encoder) Encode(v interface{}) error {
 	ctx.inline = enc.tablesInline

 	if v == nil {
-		return fmt.Errorf("toml: cannot encode a nil interface")
+		return errors.New("toml: cannot encode a nil interface")
 	}

 	b, err := enc.encode(b, ctx, reflect.ValueOf(v))
@@ -196,6 +199,7 @@ func (enc *Encoder) Encode(v interface{}) error {
 type valueOptions struct {
 	multiline bool
 	omitempty bool
+	omitzero  bool
 	commented bool
 	comment   string
 }
@@ -266,16 +270,15 @@ func (enc *Encoder) encode(b []byte, ctx encoderCtx, v reflect.Value) ([]byte, e
 	case LocalDateTime:
 		return append(b, x.String()...), nil
 	case json.Number:
-		if enc.marshalJsonNumbers {
+		if enc.marshalJSONNumbers {
 			if x == "" { /// Useful zero value.
 				return append(b, "0"...), nil
 			} else if v, err := x.Int64(); err == nil {
 				return enc.encode(b, ctx, reflect.ValueOf(v))
 			} else if f, err := x.Float64(); err == nil {
 				return enc.encode(b, ctx, reflect.ValueOf(f))
-			} else {
-				return nil, fmt.Errorf("toml: unable to convert %q to int64 or float64", x)
 			}
+			return nil, fmt.Errorf("toml: unable to convert %q to int64 or float64", x)
 		}
 	}

@@ -309,7 +312,7 @@ func (enc *Encoder) encode(b []byte, ctx encoderCtx, v reflect.Value) ([]byte, e
 		return enc.encodeSlice(b, ctx, v)
 	case reflect.Interface:
 		if v.IsNil() {
-			return nil, fmt.Errorf("toml: encoding a nil interface is not supported")
+			return nil, errors.New("toml: encoding a nil interface is not supported")
 		}

 		return enc.encode(b, ctx, v.Elem())
@@ -326,28 +329,30 @@ func (enc *Encoder) encode(b []byte, ctx encoderCtx, v reflect.Value) ([]byte, e
 	case reflect.Float32:
 		f := v.Float()

-		if math.IsNaN(f) {
+		switch {
+		case math.IsNaN(f):
 			b = append(b, "nan"...)
-		} else if f > math.MaxFloat32 {
+		case f > math.MaxFloat32:
 			b = append(b, "inf"...)
-		} else if f < -math.MaxFloat32 {
+		case f < -math.MaxFloat32:
 			b = append(b, "-inf"...)
-		} else if math.Trunc(f) == f {
+		case math.Trunc(f) == f:
 			b = strconv.AppendFloat(b, f, 'f', 1, 32)
-		} else {
+		default:
 			b = strconv.AppendFloat(b, f, 'f', -1, 32)
 		}
 	case reflect.Float64:
 		f := v.Float()
-		if math.IsNaN(f) {
+		switch {
+		case math.IsNaN(f):
 			b = append(b, "nan"...)
-		} else if f > math.MaxFloat64 {
+		case f > math.MaxFloat64:
 			b = append(b, "inf"...)
-		} else if f < -math.MaxFloat64 {
+		case f < -math.MaxFloat64:
 			b = append(b, "-inf"...)
-		} else if math.Trunc(f) == f {
+		case math.Trunc(f) == f:
 			b = strconv.AppendFloat(b, f, 'f', 1, 64)
-		} else {
+		default:
 			b = strconv.AppendFloat(b, f, 'f', -1, 64)
 		}
 	case reflect.Bool:
@@ -384,6 +389,31 @@ func shouldOmitEmpty(options valueOptions, v reflect.Value) bool {
 	return options.omitempty && isEmptyValue(v)
 }

+func shouldOmitZero(options valueOptions, v reflect.Value) bool {
+	if !options.omitzero {
+		return false
+	}
+
+	// Check if the type implements isZeroer interface (has a custom IsZero method).
+	if v.Type().Implements(isZeroerType) {
+		return v.Interface().(isZeroer).IsZero()
+	}
+
+	// Check if pointer type implements isZeroer.
+	if reflect.PointerTo(v.Type()).Implements(isZeroerType) {
+		if v.CanAddr() {
+			return v.Addr().Interface().(isZeroer).IsZero()
+		}
+		// Create a temporary addressable copy to call the pointer receiver method.
+		pv := reflect.New(v.Type())
+		pv.Elem().Set(v)
+		return pv.Interface().(isZeroer).IsZero()
+	}
+
+	// Fall back to reflect's IsZero for types without custom IsZero method.
+	return v.IsZero()
+}
+
 func (enc *Encoder) encodeKv(b []byte, ctx encoderCtx, options valueOptions, v reflect.Value) ([]byte, error) {
 	var err error

@@ -434,8 +464,9 @@ func isEmptyValue(v reflect.Value) bool {
 		return v.Float() == 0
 	case reflect.Interface, reflect.Ptr:
 		return v.IsNil()
+	default:
+		return false
 	}
-	return false
 }

 func isEmptyStruct(v reflect.Value) bool {
@@ -479,7 +510,7 @@ func (enc *Encoder) encodeString(b []byte, v string, options valueOptions) []byt
 func needsQuoting(v string) bool {
 	// TODO: vectorize
 	for _, b := range []byte(v) {
-		if b == '\'' || b == '\r' || b == '\n' || characters.InvalidAscii(b) {
+		if b == '\'' || b == '\r' || b == '\n' || characters.InvalidASCII(b) {
 			return true
 		}
 	}
@@ -517,12 +548,26 @@ func (enc *Encoder) encodeQuotedString(multiline bool, b []byte, v string) []byt
 		del = 0x7f
 	)

-	for _, r := range []byte(v) {
+	bv := []byte(v)
+	for i := 0; i < len(bv); i++ {
+		r := bv[i]
 		switch r {
 		case '\\':
 			b = append(b, `\\`...)
 		case '"':
-			b = append(b, `\"`...)
+			if multiline {
+				// Quotation marks do not need to be quoted in multiline strings unless
+				// it contains 3 consecutive. If 3+ quotes appear, quote all of them
+				// because it's visually better
+				if i+2 > len(bv) || bv[i+1] != '"' || bv[i+2] != '"' {
+					b = append(b, r)
+				} else {
+					b = append(b, `\"\"\"`...)
+					i += 2
+				}
+			} else {
+				b = append(b, `\"`...)
+			}
 		case '\b':
 			b = append(b, `\b`...)
 		case '\f':
@@ -559,9 +604,9 @@ func (enc *Encoder) encodeUnquotedKey(b []byte, v string) []byte {
 	return append(b, v...)
 }

-func (enc *Encoder) encodeTableHeader(ctx encoderCtx, b []byte) ([]byte, error) {
+func (enc *Encoder) encodeTableHeader(ctx encoderCtx, b []byte) []byte {
 	if len(ctx.parentKey) == 0 {
-		return b, nil
+		return b
 	}

 	b = enc.encodeComment(ctx.indent, ctx.options.comment, b)
@@ -581,10 +626,9 @@ func (enc *Encoder) encodeTableHeader(ctx encoderCtx, b []byte) ([]byte, error)

 	b = append(b, "]\n"...)

-	return b, nil
+	return b
 }

-//nolint:cyclop
 func (enc *Encoder) encodeKey(b []byte, k string) []byte {
 	needsQuotation := false
 	cannotUseLiteral := false
@@ -621,30 +665,33 @@ func (enc *Encoder) encodeKey(b []byte, k string) []byte {

 func (enc *Encoder) keyToString(k reflect.Value) (string, error) {
 	keyType := k.Type()
-	switch {
-	case keyType.Kind() == reflect.String:
-		return k.String(), nil
-
-	case keyType.Implements(textMarshalerType):
+	if keyType.Implements(textMarshalerType) {
 		keyB, err := k.Interface().(encoding.TextMarshaler).MarshalText()
 		if err != nil {
 			return "", fmt.Errorf("toml: error marshalling key %v from text: %w", k, err)
 		}
 		return string(keyB), nil
+	}

-	case keyType.Kind() == reflect.Int || keyType.Kind() == reflect.Int8 || keyType.Kind() == reflect.Int16 || keyType.Kind() == reflect.Int32 || keyType.Kind() == reflect.Int64:
+	switch keyType.Kind() {
+	case reflect.String:
+		return k.String(), nil
+
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 		return strconv.FormatInt(k.Int(), 10), nil

-	case keyType.Kind() == reflect.Uint || keyType.Kind() == reflect.Uint8 || keyType.Kind() == reflect.Uint16 || keyType.Kind() == reflect.Uint32 || keyType.Kind() == reflect.Uint64:
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
 		return strconv.FormatUint(k.Uint(), 10), nil

-	case keyType.Kind() == reflect.Float32:
+	case reflect.Float32:
 		return strconv.FormatFloat(k.Float(), 'f', -1, 32), nil

-	case keyType.Kind() == reflect.Float64:
+	case reflect.Float64:
 		return strconv.FormatFloat(k.Float(), 'f', -1, 64), nil
+
+	default:
+		return "", fmt.Errorf("toml: type %s is not supported as a map key", keyType.Kind())
 	}
-	return "", fmt.Errorf("toml: type %s is not supported as a map key", keyType.Kind())
 }

 func (enc *Encoder) encodeMap(b []byte, ctx encoderCtx, v reflect.Value) ([]byte, error) {
@@ -657,8 +704,18 @@ func (enc *Encoder) encodeMap(b []byte, ctx encoderCtx, v reflect.Value) ([]byte
 	for iter.Next() {
 		v := iter.Value()

-		if isNil(v) {
-			continue
+		// Handle nil values: convert nil pointers to zero value,
+		// skip nil interfaces and nil maps.
+		switch v.Kind() {
+		case reflect.Ptr:
+			if v.IsNil() {
+				v = reflect.Zero(v.Type().Elem())
+			}
+		case reflect.Interface, reflect.Map:
+			if v.IsNil() {
+				continue
+			}
+		default:
 		}

 		k, err := enc.keyToString(iter.Key())
@@ -748,9 +805,8 @@ func walkStruct(ctx encoderCtx, t *table, v reflect.Value) {
 					walkStruct(ctx, t, f.Elem())
 				}
 				continue
-			} else {
-				k = fieldType.Name
 			}
+			k = fieldType.Name
 		}

 		if isNil(f) {
@@ -760,6 +816,7 @@ func walkStruct(ctx encoderCtx, t *table, v reflect.Value) {
 		options := valueOptions{
 			multiline: opts.multiline,
 			omitempty: opts.omitempty,
+			omitzero:  opts.omitzero,
 			commented: opts.commented,
 			comment:   fieldType.Tag.Get("comment"),
 		}
@@ -820,6 +877,7 @@ type tagOptions struct {
 	multiline bool
 	inline    bool
 	omitempty bool
+	omitzero  bool
 	commented bool
 }

@@ -832,7 +890,7 @@ func parseTag(tag string) (string, tagOptions) {
 	}

 	raw := tag[idx+1:]
-	tag = string(tag[:idx])
+	tag = tag[:idx]
 	for raw != "" {
 		var o string
 		i := strings.Index(raw, ",")
@@ -848,6 +906,8 @@ func parseTag(tag string) (string, tagOptions) {
 			opts.inline = true
 		case "omitempty":
 			opts.omitempty = true
+		case "omitzero":
+			opts.omitzero = true
 		case "commented":
 			opts.commented = true
 		}
@@ -866,10 +926,7 @@ func (enc *Encoder) encodeTable(b []byte, ctx encoderCtx, t table) ([]byte, erro
 	}

 	if !ctx.skipTableHeader {
-		b, err = enc.encodeTableHeader(ctx, b)
-		if err != nil {
-			return nil, err
-		}
+		b = enc.encodeTableHeader(ctx, b)

 		if enc.indentTables && len(ctx.parentKey) > 0 {
 			ctx.indent++
@@ -882,6 +939,9 @@ func (enc *Encoder) encodeTable(b []byte, ctx encoderCtx, t table) ([]byte, erro
 		if shouldOmitEmpty(kv.Options, kv.Value) {
 			continue
 		}
+		if kv.Options.omitzero && shouldOmitZero(kv.Options, kv.Value) {
+			continue
+		}
 		hasNonEmptyKV = true

 		ctx.setKey(kv.Key)
@@ -901,6 +961,9 @@ func (enc *Encoder) encodeTable(b []byte, ctx encoderCtx, t table) ([]byte, erro
 		if shouldOmitEmpty(table.Options, table.Value) {
 			continue
 		}
+		if table.Options.omitzero && shouldOmitZero(table.Options, table.Value) {
+			continue
+		}
 		if first {
 			first = false
 			if hasNonEmptyKV {
@@ -935,6 +998,9 @@ func (enc *Encoder) encodeTableInline(b []byte, ctx encoderCtx, t table) ([]byte
 		if shouldOmitEmpty(kv.Options, kv.Value) {
 			continue
 		}
+		if kv.Options.omitzero && shouldOmitZero(kv.Options, kv.Value) {
+			continue
+		}

 		if first {
 			first = false
@@ -963,11 +1029,14 @@ func willConvertToTable(ctx encoderCtx, v reflect.Value) bool {
 	if !v.IsValid() {
 		return false
 	}
-	if v.Type() == timeType || v.Type().Implements(textMarshalerType) || (v.Kind() != reflect.Ptr && v.CanAddr() && reflect.PointerTo(v.Type()).Implements(textMarshalerType)) {
+	t := v.Type()
+	if t == timeType || t.Implements(textMarshalerType) {
+		return false
+	}
+	if v.Kind() != reflect.Ptr && v.CanAddr() && reflect.PointerTo(t).Implements(textMarshalerType) {
 		return false
 	}

-	t := v.Type()
 	switch t.Kind() {
 	case reflect.Map, reflect.Struct:
 		return !ctx.inline
@@ -1,7 +1,6 @@
 package toml

 import (
-	"github.com/pelletier/go-toml/v2/internal/danger"
 	"github.com/pelletier/go-toml/v2/internal/tracker"
 	"github.com/pelletier/go-toml/v2/unstable"
 )
@@ -13,6 +12,9 @@ type strict struct {
 	key tracker.KeyTracker

 	missing []unstable.ParserError
+
+	// Reference to the document for computing key ranges.
+	doc []byte
 }

 func (s *strict) EnterTable(node *unstable.Node) {
@@ -53,7 +55,7 @@ func (s *strict) MissingTable(node *unstable.Node) {
 	}

 	s.missing = append(s.missing, unstable.ParserError{
-		Highlight: keyLocation(node),
+		Highlight: s.keyLocation(node),
 		Message:   "missing table",
 		Key:       s.key.Key(),
 	})
@@ -65,7 +67,7 @@ func (s *strict) MissingField(node *unstable.Node) {
 	}

 	s.missing = append(s.missing, unstable.ParserError{
-		Highlight: keyLocation(node),
+		Highlight: s.keyLocation(node),
 		Message:   "missing field",
 		Key:       s.key.Key(),
 	})
@@ -88,7 +90,7 @@ func (s *strict) Error(doc []byte) error {
 	return err
 }

-func keyLocation(node *unstable.Node) []byte {
+func (s *strict) keyLocation(node *unstable.Node) []byte {
 	k := node.Key()

 	hasOne := k.Next()
@@ -96,12 +98,17 @@ func keyLocation(node *unstable.Node) []byte {
 		panic("should not be called with empty key")
 	}

-	start := k.Node().Data
-	end := k.Node().Data
+	// Get the range from the first key to the last key.
+	firstRaw := k.Node().Raw
+	lastRaw := firstRaw

 	for k.Next() {
-		end = k.Node().Data
+		lastRaw = k.Node().Raw
 	}

-	return danger.BytesRange(start, end)
+	// Compute the slice from the document using the ranges.
+	start := firstRaw.Offset
+	end := lastRaw.Offset + lastRaw.Length
+
+	return s.doc[start:end]
 }
@@ -0,0 +1,597 @@
+#!/usr/bin/env bash
+
+set -uo pipefail
+
+# Colors for output
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+BLUE='\033[0;34m'
+NC='\033[0m' # No Color
+
+# Go versions to test (1.11 through 1.26)
+GO_VERSIONS=(
+    "1.11"
+    "1.12"
+    "1.13"
+    "1.14"
+    "1.15"
+    "1.16"
+    "1.17"
+    "1.18"
+    "1.19"
+    "1.20"
+    "1.21"
+    "1.22"
+    "1.23"
+    "1.24"
+    "1.25"
+    "1.26"
+)
+
+# Default values
+PARALLEL=true
+VERBOSE=false
+OUTPUT_DIR="test-results"
+DOCKER_TIMEOUT="10m"
+
+usage() {
+    cat << EOF
+Usage: $0 [OPTIONS] [GO_VERSIONS...]
+
+Test go-toml across multiple Go versions using Docker containers.
+
+The script reports the lowest continuous supported Go version (where all subsequent 
+versions pass) and only exits with non-zero status if either of the two most recent 
+Go versions fail, indicating immediate attention is needed.
+
+Note: For Go versions < 1.21, the script automatically updates go.mod to match the 
+target version, but older versions may still fail due to missing standard library 
+features (e.g., the 'slices' package introduced in Go 1.21).
+
+OPTIONS:
+    -h, --help          Show this help message
+    -s, --sequential    Run tests sequentially instead of in parallel
+    -v, --verbose       Enable verbose output
+    -o, --output DIR    Output directory for test results (default: test-results)
+    -t, --timeout TIME  Docker timeout for each test (default: 10m)
+    --list              List available Go versions and exit
+
+ARGUMENTS:
+    GO_VERSIONS         Specific Go versions to test (default: all supported versions)
+                        Examples: 1.21 1.22 1.23
+
+EXAMPLES:
+    $0                          # Test all Go versions in parallel
+    $0 --sequential             # Test all Go versions sequentially
+    $0 1.21 1.22 1.23          # Test specific versions
+    $0 --verbose --output ./results 1.25 1.26  # Verbose output to custom directory
+
+EXIT CODES:
+    0                   Recent Go versions pass (good compatibility)
+    1                   Recent Go versions fail (needs attention) or script error
+
+EOF
+}
+
+log() {
+    echo -e "${BLUE}[$(date +'%H:%M:%S')]${NC} $*" >&2
+}
+
+log_success() {
+    echo -e "${GREEN}[$(date +'%H:%M:%S')] ✓${NC} $*" >&2
+}
+
+log_error() {
+    echo -e "${RED}[$(date +'%H:%M:%S')] ✗${NC} $*" >&2
+}
+
+log_warning() {
+    echo -e "${YELLOW}[$(date +'%H:%M:%S')] ⚠${NC} $*" >&2
+}
+
+# Parse command line arguments
+while [[ $# -gt 0 ]]; do
+    case $1 in
+        -h|--help)
+            usage
+            exit 0
+            ;;
+        -s|--sequential)
+            PARALLEL=false
+            shift
+            ;;
+        -v|--verbose)
+            VERBOSE=true
+            shift
+            ;;
+        -o|--output)
+            OUTPUT_DIR="$2"
+            shift 2
+            ;;
+        -t|--timeout)
+            DOCKER_TIMEOUT="$2"
+            shift 2
+            ;;
+        --list)
+            echo "Available Go versions:"
+            printf '%s\n' "${GO_VERSIONS[@]}"
+            exit 0
+            ;;
+        -*)
+            echo "Unknown option: $1" >&2
+            usage
+            exit 1
+            ;;
+        *)
+            # Remaining arguments are Go versions
+            break
+            ;;
+    esac
+done
+
+# If specific versions provided, use those instead of defaults
+if [[ $# -gt 0 ]]; then
+    GO_VERSIONS=("$@")
+fi
+
+# Validate Go versions
+for version in "${GO_VERSIONS[@]}"; do
+    if ! [[ "$version" =~ ^1\.(1[1-9]|2[0-6])$ ]]; then
+        log_error "Invalid Go version: $version. Supported versions: 1.11-1.26"
+        exit 1
+    fi
+done
+
+# Check if Docker is available
+if ! command -v docker &> /dev/null; then
+    log_error "Docker is required but not installed or not in PATH"
+    exit 1
+fi
+
+# Check if Docker daemon is running
+if ! docker info &> /dev/null; then
+    log_error "Docker daemon is not running"
+    exit 1
+fi
+
+# Create output directory
+mkdir -p "$OUTPUT_DIR"
+
+# Function to test a single Go version
+test_go_version() {
+    local go_version="$1"
+    local container_name="go-toml-test-${go_version}"
+    local result_file="${OUTPUT_DIR}/go-${go_version}.txt"
+    local dockerfile_content
+
+    log "Testing Go $go_version..."
+
+    # Create a temporary Dockerfile for this version
+    # For Go versions < 1.21, we need to update go.mod to match the Go version
+    local needs_go_mod_update=false
+    if [[ $(echo "$go_version 1.21" | tr ' ' '\n' | sort -V | head -n1) == "$go_version" && "$go_version" != "1.21" ]]; then
+        needs_go_mod_update=true
+    fi
+    
+    dockerfile_content="FROM golang:${go_version}-alpine
+
+# Install git (required for go mod)
+RUN apk add --no-cache git
+
+# Set working directory
+WORKDIR /app
+
+# Copy source code
+COPY . ."
+
+    # Add go.mod update step for older Go versions
+    if [[ "$needs_go_mod_update" == true ]]; then
+        dockerfile_content="$dockerfile_content
+
+# Update go.mod to match Go version (required for Go < 1.21)
+RUN if [ -f go.mod ]; then sed -i 's/^go [0-9]\\+\\.[0-9]\\+\\(\\.[0-9]\\+\\)\\?/go $go_version/' go.mod; fi
+
+# Note: Go versions < 1.21 may fail due to missing standard library packages (e.g., slices)
+# This is expected for projects that use Go 1.21+ features"
+    fi
+    
+    dockerfile_content="$dockerfile_content
+
+# Run tests
+CMD [\"sh\", \"-c\", \"go version && echo '--- Running go test ./... ---' && go test ./...\"]"
+
+    # Create temporary directory for this test
+    local temp_dir
+    temp_dir=$(mktemp -d)
+
+    # Copy source to temp directory (excluding test results and git)
+    rsync -a --exclude="$OUTPUT_DIR" --exclude=".git" --exclude="*.test" . "$temp_dir/"
+
+    # Create Dockerfile in temp directory
+    echo "$dockerfile_content" > "$temp_dir/Dockerfile"
+
+    # Build and run container
+    local exit_code=0
+    local output
+
+    if $VERBOSE; then
+        log "Building Docker image for Go $go_version..."
+    fi
+
+    # Capture both stdout and stderr, and the exit code
+    if output=$(cd "$temp_dir" && timeout "$DOCKER_TIMEOUT" docker build -t "$container_name" . 2>&1 && \
+                timeout "$DOCKER_TIMEOUT" docker run --rm "$container_name" 2>&1); then
+        log_success "Go $go_version: PASSED"
+        echo "PASSED" > "${result_file}.status"
+    else
+        exit_code=$?
+        log_error "Go $go_version: FAILED (exit code: $exit_code)"
+        echo "FAILED" > "${result_file}.status"
+    fi
+
+    # Save full output
+    echo "$output" > "$result_file"
+
+    # Clean up
+    docker rmi "$container_name" &> /dev/null || true
+    rm -rf "$temp_dir"
+
+    if $VERBOSE; then
+        echo "--- Go $go_version output ---"
+        echo "$output"
+        echo "--- End Go $go_version output ---"
+    fi
+
+    return $exit_code
+}
+
+# Function to run tests in parallel
+run_parallel() {
+    local pids=()
+    local failed_versions=()
+
+    log "Starting parallel tests for ${#GO_VERSIONS[@]} Go versions..."
+
+    # Start all tests in background
+    for version in "${GO_VERSIONS[@]}"; do
+        test_go_version "$version" &
+        pids+=($!)
+    done
+
+    # Wait for all tests to complete
+    for i in "${!pids[@]}"; do
+        local pid=${pids[$i]}
+        local version=${GO_VERSIONS[$i]}
+
+        if ! wait $pid; then
+            failed_versions+=("$version")
+        fi
+    done
+
+    return ${#failed_versions[@]}
+}
+
+# Function to run tests sequentially
+run_sequential() {
+    local failed_versions=()
+
+    log "Starting sequential tests for ${#GO_VERSIONS[@]} Go versions..."
+
+    for version in "${GO_VERSIONS[@]}"; do
+        if ! test_go_version "$version"; then
+            failed_versions+=("$version")
+        fi
+    done
+
+    return ${#failed_versions[@]}
+}
+
+# Main execution
+main() {
+    local start_time
+    start_time=$(date +%s)
+
+    log "Starting Go version compatibility tests..."
+    log "Testing versions: ${GO_VERSIONS[*]}"
+    log "Output directory: $OUTPUT_DIR"
+    log "Parallel execution: $PARALLEL"
+
+    local failed_count
+    if $PARALLEL; then
+        run_parallel
+        failed_count=$?
+    else
+        run_sequential
+        failed_count=$?
+    fi
+
+    local end_time
+    end_time=$(date +%s)
+    local duration=$((end_time - start_time))
+
+    # Collect results for display
+    local passed_versions=()
+    local failed_versions=()
+    local unknown_versions=()
+    local passed_count=0
+
+    for version in "${GO_VERSIONS[@]}"; do
+        local status_file="${OUTPUT_DIR}/go-${version}.txt.status"
+        if [[ -f "$status_file" ]]; then
+            local status
+            status=$(cat "$status_file")
+            if [[ "$status" == "PASSED" ]]; then
+                passed_versions+=("$version")
+                ((passed_count++))
+            else
+                failed_versions+=("$version")
+            fi
+        else
+            unknown_versions+=("$version")
+        fi
+    done
+
+    # Generate summary report
+    local summary_file="${OUTPUT_DIR}/summary.txt"
+    {
+        echo "Go Version Compatibility Test Summary"
+        echo "====================================="
+        echo "Date: $(date)"
+        echo "Duration: ${duration}s"
+        echo "Parallel: $PARALLEL"
+        echo ""
+        echo "Results:"
+
+        for version in "${GO_VERSIONS[@]}"; do
+            local status_file="${OUTPUT_DIR}/go-${version}.txt.status"
+            if [[ -f "$status_file" ]]; then
+                local status
+                status=$(cat "$status_file")
+                if [[ "$status" == "PASSED" ]]; then
+                    echo "  Go $version: ✓ PASSED"
+                else
+                    echo "  Go $version: ✗ FAILED"
+                fi
+            else
+                echo "  Go $version: ? UNKNOWN (no status file)"
+            fi
+        done
+
+        echo ""
+        echo "Summary: $passed_count/${#GO_VERSIONS[@]} versions passed"
+
+        if [[ $failed_count -gt 0 ]]; then
+            echo ""
+            echo "Failed versions details:"
+            for version in "${failed_versions[@]}"; do
+                echo ""
+                echo "--- Go $version (FAILED) ---"
+                local result_file="${OUTPUT_DIR}/go-${version}.txt"
+                if [[ -f "$result_file" ]]; then
+                    tail -n 30 "$result_file"
+                fi
+            done
+        fi
+    } > "$summary_file"
+
+        # Find lowest continuous supported version and check recent versions
+    local lowest_continuous_version=""
+    local recent_versions_failed=false
+    
+    # Sort versions to ensure proper order
+    local sorted_versions=()
+    for version in "${GO_VERSIONS[@]}"; do
+        sorted_versions+=("$version")
+    done
+    # Sort versions numerically (1.11, 1.12, ..., 1.25)
+    IFS=$'\n' sorted_versions=($(sort -V <<< "${sorted_versions[*]}"))
+    
+    # Find lowest continuous supported version (all versions from this point onwards pass)
+    for version in "${sorted_versions[@]}"; do
+        local status_file="${OUTPUT_DIR}/go-${version}.txt.status"
+        local all_subsequent_pass=true
+        
+        # Check if this version and all subsequent versions pass
+        local found_current=false
+        for check_version in "${sorted_versions[@]}"; do
+            if [[ "$check_version" == "$version" ]]; then
+                found_current=true
+            fi
+            
+            if [[ "$found_current" == true ]]; then
+                local check_status_file="${OUTPUT_DIR}/go-${check_version}.txt.status"
+                if [[ -f "$check_status_file" ]]; then
+                    local status
+                    status=$(cat "$check_status_file")
+                    if [[ "$status" != "PASSED" ]]; then
+                        all_subsequent_pass=false
+                        break
+                    fi
+                else
+                    all_subsequent_pass=false
+                    break
+                fi
+            fi
+        done
+        
+        if [[ "$all_subsequent_pass" == true ]]; then
+            lowest_continuous_version="$version"
+            break
+        fi
+    done
+    
+    # Check if the two most recent versions failed
+    local num_versions=${#sorted_versions[@]}
+    if [[ $num_versions -ge 2 ]]; then
+        local second_recent="${sorted_versions[$((num_versions-2))]}"
+        local most_recent="${sorted_versions[$((num_versions-1))]}"
+        
+        local second_recent_status_file="${OUTPUT_DIR}/go-${second_recent}.txt.status"
+        local most_recent_status_file="${OUTPUT_DIR}/go-${most_recent}.txt.status"
+        
+        local second_recent_failed=false
+        local most_recent_failed=false
+        
+        if [[ -f "$second_recent_status_file" ]]; then
+            local status
+            status=$(cat "$second_recent_status_file")
+            if [[ "$status" != "PASSED" ]]; then
+                second_recent_failed=true
+            fi
+        else
+            second_recent_failed=true
+        fi
+        
+        if [[ -f "$most_recent_status_file" ]]; then
+            local status
+            status=$(cat "$most_recent_status_file")
+            if [[ "$status" != "PASSED" ]]; then
+                most_recent_failed=true
+            fi
+        else
+            most_recent_failed=true
+        fi
+        
+        if [[ "$second_recent_failed" == true || "$most_recent_failed" == true ]]; then
+            recent_versions_failed=true
+        fi
+    elif [[ $num_versions -eq 1 ]]; then
+        # Only one version tested, check if it's the most recent and failed
+        local only_version="${sorted_versions[0]}"
+        local only_status_file="${OUTPUT_DIR}/go-${only_version}.txt.status"
+        
+        if [[ -f "$only_status_file" ]]; then
+            local status
+            status=$(cat "$only_status_file")
+            if [[ "$status" != "PASSED" ]]; then
+                recent_versions_failed=true
+            fi
+        else
+            recent_versions_failed=true
+        fi
+    fi
+    
+    # Display summary
+    echo ""
+    log "Test completed in ${duration}s"
+    log "Summary report: $summary_file"
+    
+    echo ""
+    echo "========================================"
+    echo "           FINAL RESULTS"
+    echo "========================================"
+    echo ""
+    
+    # Display passed versions
+    if [[ ${#passed_versions[@]} -gt 0 ]]; then
+        log_success "PASSED (${#passed_versions[@]}/${#GO_VERSIONS[@]}):"
+        # Sort passed versions for display
+        local sorted_passed=()
+        for version in "${sorted_versions[@]}"; do
+            for passed_version in "${passed_versions[@]}"; do
+                if [[ "$version" == "$passed_version" ]]; then
+                    sorted_passed+=("$version")
+                    break
+                fi
+            done
+        done
+        for version in "${sorted_passed[@]}"; do
+            echo -e "  ${GREEN}✓${NC} Go $version"
+        done
+        echo ""
+    fi
+    
+    # Display failed versions
+    if [[ ${#failed_versions[@]} -gt 0 ]]; then
+        log_error "FAILED (${#failed_versions[@]}/${#GO_VERSIONS[@]}):"
+        # Sort failed versions for display
+        local sorted_failed=()
+        for version in "${sorted_versions[@]}"; do
+            for failed_version in "${failed_versions[@]}"; do
+                if [[ "$version" == "$failed_version" ]]; then
+                    sorted_failed+=("$version")
+                    break
+                fi
+            done
+        done
+        for version in "${sorted_failed[@]}"; do
+            echo -e "  ${RED}✗${NC} Go $version"
+        done
+        echo ""
+        
+        # Show failure details
+        echo "========================================"
+        echo "         FAILURE DETAILS"
+        echo "========================================"
+        echo ""
+        
+        for version in "${sorted_failed[@]}"; do
+            echo -e "${RED}--- Go $version FAILURE LOGS (last 30 lines) ---${NC}"
+            local result_file="${OUTPUT_DIR}/go-${version}.txt"
+            if [[ -f "$result_file" ]]; then
+                tail -n 30 "$result_file" | sed 's/^/  /'
+            else
+                echo "  No log file found: $result_file"
+            fi
+            echo ""
+        done
+    fi
+    
+    # Display unknown versions
+    if [[ ${#unknown_versions[@]} -gt 0 ]]; then
+        log_warning "UNKNOWN (${#unknown_versions[@]}/${#GO_VERSIONS[@]}):"
+        for version in "${unknown_versions[@]}"; do
+            echo -e "  ${YELLOW}?${NC} Go $version (no status file)"
+        done
+        echo ""
+    fi
+    
+    echo "========================================"
+    echo "         COMPATIBILITY SUMMARY"
+    echo "========================================"
+    echo ""
+    
+    if [[ -n "$lowest_continuous_version" ]]; then
+        log_success "Lowest continuous supported version: Go $lowest_continuous_version"
+        echo "  (All versions from Go $lowest_continuous_version onwards pass)"
+    else
+        log_error "No continuous version support found"
+        echo "  (No version has all subsequent versions passing)"
+    fi
+    
+    echo ""
+    echo "========================================"
+    echo "Full detailed logs available in: $OUTPUT_DIR"
+    echo "========================================"
+    
+    # Determine exit code based on recent versions
+    if [[ "$recent_versions_failed" == true ]]; then
+        log_error "OVERALL RESULT: Recent Go versions failed - this needs attention!"
+        if [[ -n "$lowest_continuous_version" ]]; then
+            echo "Note: Continuous support starts from Go $lowest_continuous_version"
+        fi
+        exit 1
+    else
+        log_success "OVERALL RESULT: Recent Go versions pass - compatibility looks good!"
+        if [[ -n "$lowest_continuous_version" ]]; then
+            echo "Continuous support starts from Go $lowest_continuous_version"
+        fi
+        exit 0
+    fi
+}
+
+# Trap to clean up on exit
+cleanup() {
+    # Kill any remaining background processes
+    jobs -p | xargs -r kill 2>/dev/null || true
+
+    # Clean up any remaining Docker containers
+    docker ps -q --filter "name=go-toml-test-" | xargs -r docker stop 2>/dev/null || true
+    docker images -q --filter "reference=go-toml-test-*" | xargs -r docker rmi 2>/dev/null || true
+}
+
+trap cleanup EXIT
+
+# Run main function
+main
@@ -6,9 +6,18 @@ import (
 	"time"
 )

-var timeType = reflect.TypeOf((*time.Time)(nil)).Elem()
-var textMarshalerType = reflect.TypeOf((*encoding.TextMarshaler)(nil)).Elem()
-var textUnmarshalerType = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
-var mapStringInterfaceType = reflect.TypeOf(map[string]interface{}(nil))
-var sliceInterfaceType = reflect.TypeOf([]interface{}(nil))
-var stringType = reflect.TypeOf("")
+// isZeroer is used to check if a type has a custom IsZero method.
+// This allows custom types to define their own zero-value semantics.
+type isZeroer interface {
+	IsZero() bool
+}
+
+var (
+	timeType               = reflect.TypeOf((*time.Time)(nil)).Elem()
+	textMarshalerType      = reflect.TypeOf((*encoding.TextMarshaler)(nil)).Elem()
+	textUnmarshalerType    = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
+	isZeroerType           = reflect.TypeOf((*isZeroer)(nil)).Elem()
+	mapStringInterfaceType = reflect.TypeOf(map[string]interface{}(nil))
+	sliceInterfaceType     = reflect.TypeOf([]interface{}(nil))
+	stringType             = reflect.TypeOf("")
+)
@@ -12,7 +12,6 @@ import (
 	"sync/atomic"
 	"time"

-	"github.com/pelletier/go-toml/v2/internal/danger"
 	"github.com/pelletier/go-toml/v2/internal/tracker"
 	"github.com/pelletier/go-toml/v2/unstable"
 )
@@ -57,13 +56,18 @@ func (d *Decoder) DisallowUnknownFields() *Decoder {

 // EnableUnmarshalerInterface allows to enable unmarshaler interface.
 //
-// With this feature enabled, types implementing the unstable/Unmarshaler
+// With this feature enabled, types implementing the unstable.Unmarshaler
 // interface can be decoded from any structure of the document. It allows types
 // that don't have a straightforward TOML representation to provide their own
 // decoding logic.
 //
-// Currently, types can only decode from a single value. Tables and array tables
-// are not supported.
+// The UnmarshalTOML method receives raw TOML bytes:
+//   - For single values: the raw value bytes (e.g., `"hello"` for a string)
+//   - For tables: all key-value lines belonging to that table
+//   - For inline tables/arrays: the raw bytes of the inline structure
+//
+// The unstable.RawMessage type can be used to capture raw TOML bytes for
+// later processing, similar to json.RawMessage.
 //
 // *Unstable:* This method does not follow the compatibility guarantees of
 // semver. It can be changed or removed without a new major version being
@@ -123,6 +127,7 @@ func (d *Decoder) Decode(v interface{}) error {
 	dec := decoder{
 		strict: strict{
 			Enabled: d.strict,
+			doc:     b,
 		},
 		unmarshalerInterface: d.unmarshalerInterface,
 	}
@@ -226,7 +231,7 @@ func (d *decoder) FromParser(v interface{}) error {
 	}

 	if r.IsNil() {
-		return fmt.Errorf("toml: decoding pointer target cannot be nil")
+		return errors.New("toml: decoding pointer target cannot be nil")
 	}

 	r = r.Elem()
@@ -273,7 +278,7 @@ func (d *decoder) handleRootExpression(expr *unstable.Node, v reflect.Value) err
 	var err error
 	var first bool // used for to clear array tables on first use

-	if !(d.skipUntilTable && expr.Kind == unstable.KeyValue) {
+	if !d.skipUntilTable || expr.Kind != unstable.KeyValue {
 		first, err = d.seen.CheckExpression(expr)
 		if err != nil {
 			return err
@@ -378,7 +383,7 @@ func (d *decoder) handleArrayTableCollectionLast(key unstable.Iterator, v reflec
 	case reflect.Array:
 		idx := d.arrayIndex(true, v)
 		if idx >= v.Len() {
-			return v, fmt.Errorf("%s at position %d", d.typeMismatchError("array table", v.Type()), idx)
+			return v, fmt.Errorf("%w at position %d", d.typeMismatchError("array table", v.Type()), idx)
 		}
 		elem := v.Index(idx)
 		_, err := d.handleArrayTable(key, elem)
@@ -416,27 +421,51 @@ func (d *decoder) handleArrayTableCollection(key unstable.Iterator, v reflect.Va

 		return v, nil
 	case reflect.Slice:
-		elem := v.Index(v.Len() - 1)
+		// Create a new element when the slice is empty; otherwise operate on
+		// the last element.
+		var (
+			elem    reflect.Value
+			created bool
+		)
+		if v.Len() == 0 {
+			created = true
+			elemType := v.Type().Elem()
+			if elemType.Kind() == reflect.Interface {
+				elem = makeMapStringInterface()
+			} else {
+				elem = reflect.New(elemType).Elem()
+			}
+		} else {
+			elem = v.Index(v.Len() - 1)
+		}
+
 		x, err := d.handleArrayTable(key, elem)
 		if err != nil || d.skipUntilTable {
 			return reflect.Value{}, err
 		}
 		if x.IsValid() {
-			elem.Set(x)
+			if created {
+				elem = x
+			} else {
+				elem.Set(x)
+			}
 		}

+		if created {
+			return reflect.Append(v, elem), nil
+		}
 		return v, err
 	case reflect.Array:
 		idx := d.arrayIndex(false, v)
 		if idx >= v.Len() {
-			return v, fmt.Errorf("%s at position %d", d.typeMismatchError("array table", v.Type()), idx)
+			return v, fmt.Errorf("%w at position %d", d.typeMismatchError("array table", v.Type()), idx)
 		}
 		elem := v.Index(idx)
 		_, err := d.handleArrayTable(key, elem)
 		return v, err
+	default:
+		return d.handleArrayTable(key, v)
 	}
-
-	return d.handleArrayTable(key, v)
 }

 func (d *decoder) handleKeyPart(key unstable.Iterator, v reflect.Value, nextFn handlerFn, makeFn valueMakerFn) (reflect.Value, error) {
@@ -470,7 +499,8 @@ func (d *decoder) handleKeyPart(key unstable.Iterator, v reflect.Value, nextFn h

 		mv := v.MapIndex(mk)
 		set := false
-		if !mv.IsValid() {
+		switch {
+		case !mv.IsValid():
 			// If there is no value in the map, create a new one according to
 			// the map type. If the element type is interface, create either a
 			// map[string]interface{} or a []interface{} depending on whether
@@ -483,13 +513,13 @@ func (d *decoder) handleKeyPart(key unstable.Iterator, v reflect.Value, nextFn h
 				mv = reflect.New(t).Elem()
 			}
 			set = true
-		} else if mv.Kind() == reflect.Interface {
+		case mv.Kind() == reflect.Interface:
 			mv = mv.Elem()
 			if !mv.IsValid() {
 				mv = makeFn()
 			}
 			set = true
-		} else if !mv.CanAddr() {
+		case !mv.CanAddr():
 			vt := v.Type()
 			t := vt.Elem()
 			oldmv := mv
@@ -574,18 +604,28 @@ func (d *decoder) handleArrayTablePart(key unstable.Iterator, v reflect.Value) (
 // cannot handle it.
 func (d *decoder) handleTable(key unstable.Iterator, v reflect.Value) (reflect.Value, error) {
 	if v.Kind() == reflect.Slice {
-		if v.Len() == 0 {
-			return reflect.Value{}, unstable.NewParserError(key.Node().Data, "cannot store a table in a slice")
+		// For non-empty slices, work with the last element
+		if v.Len() > 0 {
+			elem := v.Index(v.Len() - 1)
+			x, err := d.handleTable(key, elem)
+			if err != nil {
+				return reflect.Value{}, err
+			}
+			if x.IsValid() {
+				elem.Set(x)
+			}
+			return reflect.Value{}, nil
 		}
-		elem := v.Index(v.Len() - 1)
-		x, err := d.handleTable(key, elem)
-		if err != nil {
-			return reflect.Value{}, err
+		// Empty slice - check if it implements Unmarshaler (e.g., RawMessage)
+		// and we're at the end of the key path
+		if d.unmarshalerInterface && !key.Next() {
+			if v.CanAddr() && v.Addr().CanInterface() {
+				if outi, ok := v.Addr().Interface().(unstable.Unmarshaler); ok {
+					return d.handleKeyValuesUnmarshaler(outi)
+				}
+			}
 		}
-		if x.IsValid() {
-			elem.Set(x)
-		}
-		return reflect.Value{}, nil
+		return reflect.Value{}, unstable.NewParserError(key.Node().Data, "cannot store a table in a slice")
 	}
 	if key.Next() {
 		// Still scoping the key
@@ -599,6 +639,24 @@ func (d *decoder) handleTable(key unstable.Iterator, v reflect.Value) (reflect.V
 // Handle root expressions until the end of the document or the next
 // non-key-value.
 func (d *decoder) handleKeyValues(v reflect.Value) (reflect.Value, error) {
+	// Check if target implements Unmarshaler before processing key-values.
+	// This allows types to handle entire tables themselves.
+	if d.unmarshalerInterface {
+		vv := v
+		for vv.Kind() == reflect.Ptr {
+			if vv.IsNil() {
+				vv.Set(reflect.New(vv.Type().Elem()))
+			}
+			vv = vv.Elem()
+		}
+		if vv.CanAddr() && vv.Addr().CanInterface() {
+			if outi, ok := vv.Addr().Interface().(unstable.Unmarshaler); ok {
+				// Collect all key-value expressions for this table
+				return d.handleKeyValuesUnmarshaler(outi)
+			}
+		}
+	}
+
 	var rv reflect.Value
 	for d.nextExpr() {
 		expr := d.expr()
@@ -628,6 +686,41 @@ func (d *decoder) handleKeyValues(v reflect.Value) (reflect.Value, error) {
 	return rv, nil
 }

+// handleKeyValuesUnmarshaler collects all key-value expressions for a table
+// and passes them to the Unmarshaler as raw TOML bytes.
+func (d *decoder) handleKeyValuesUnmarshaler(u unstable.Unmarshaler) (reflect.Value, error) {
+	// Collect raw bytes from all key-value expressions for this table.
+	// We use the Raw field on each KeyValue expression to preserve the
+	// original formatting (whitespace, quoting style, etc.) from the document.
+	var buf []byte
+
+	for d.nextExpr() {
+		expr := d.expr()
+		if expr.Kind != unstable.KeyValue {
+			d.stashExpr()
+			break
+		}
+
+		_, err := d.seen.CheckExpression(expr)
+		if err != nil {
+			return reflect.Value{}, err
+		}
+
+		// Use the raw bytes from the original document to preserve formatting
+		if expr.Raw.Length > 0 {
+			raw := d.p.Raw(expr.Raw)
+			buf = append(buf, raw...)
+		}
+		buf = append(buf, '\n')
+	}
+
+	if err := u.UnmarshalTOML(buf); err != nil {
+		return reflect.Value{}, err
+	}
+
+	return reflect.Value{}, nil
+}
+
 type (
 	handlerFn    func(key unstable.Iterator, v reflect.Value) (reflect.Value, error)
 	valueMakerFn func() reflect.Value
@@ -672,14 +765,21 @@ func (d *decoder) handleValue(value *unstable.Node, v reflect.Value) error {
 	if d.unmarshalerInterface {
 		if v.CanAddr() && v.Addr().CanInterface() {
 			if outi, ok := v.Addr().Interface().(unstable.Unmarshaler); ok {
-				return outi.UnmarshalTOML(value)
+				// Pass raw bytes from the original document
+				return outi.UnmarshalTOML(d.p.Raw(value.Raw))
 			}
 		}
 	}

-	ok, err := d.tryTextUnmarshaler(value, v)
-	if ok || err != nil {
-		return err
+	// Only try TextUnmarshaler for scalar types. For Array and InlineTable,
+	// fall through to struct/map unmarshaling to allow flexible unmarshaling
+	// where a type can implement UnmarshalText for string values but still
+	// be populated field-by-field from a table. See issue #974.
+	if value.Kind != unstable.Array && value.Kind != unstable.InlineTable {
+		ok, err := d.tryTextUnmarshaler(value, v)
+		if ok || err != nil {
+			return err
+		}
 	}

 	switch value.Kind {
@@ -821,6 +921,9 @@ func (d *decoder) unmarshalDateTime(value *unstable.Node, v reflect.Value) error
 		return err
 	}

+	if v.Kind() != reflect.Interface && v.Type() != timeType {
+		return unstable.NewParserError(d.p.Raw(value.Raw), "%s", d.typeMismatchString("datetime", v.Type()))
+	}
 	v.Set(reflect.ValueOf(dt))
 	return nil
 }
@@ -831,14 +934,14 @@ func (d *decoder) unmarshalLocalDate(value *unstable.Node, v reflect.Value) erro
 		return err
 	}

+	if v.Kind() != reflect.Interface && v.Type() != timeType {
+		return unstable.NewParserError(d.p.Raw(value.Raw), "%s", d.typeMismatchString("local date", v.Type()))
+	}
 	if v.Type() == timeType {
-		cast := ld.AsTime(time.Local)
-		v.Set(reflect.ValueOf(cast))
+		v.Set(reflect.ValueOf(ld.AsTime(time.Local)))
 		return nil
 	}
-
 	v.Set(reflect.ValueOf(ld))
-
 	return nil
 }

@@ -852,6 +955,9 @@ func (d *decoder) unmarshalLocalTime(value *unstable.Node, v reflect.Value) erro
 		return unstable.NewParserError(rest, "extra characters at the end of a local time")
 	}

+	if v.Kind() != reflect.Interface {
+		return unstable.NewParserError(d.p.Raw(value.Raw), "%s", d.typeMismatchString("local time", v.Type()))
+	}
 	v.Set(reflect.ValueOf(lt))
 	return nil
 }
@@ -866,15 +972,14 @@ func (d *decoder) unmarshalLocalDateTime(value *unstable.Node, v reflect.Value)
 		return unstable.NewParserError(rest, "extra characters at the end of a local date time")
 	}

+	if v.Kind() != reflect.Interface && v.Type() != timeType {
+		return unstable.NewParserError(d.p.Raw(value.Raw), "%s", d.typeMismatchString("local datetime", v.Type()))
+	}
 	if v.Type() == timeType {
-		cast := ldt.AsTime(time.Local)
-
-		v.Set(reflect.ValueOf(cast))
+		v.Set(reflect.ValueOf(ldt.AsTime(time.Local)))
 		return nil
 	}
-
 	v.Set(reflect.ValueOf(ldt))
-
 	return nil
 }

@@ -929,8 +1034,9 @@ const (
 // compile time, so it is computed during initialization.
 var maxUint int64 = math.MaxInt64

-func init() {
+func init() { //nolint:gochecknoinits
 	m := uint64(^uint(0))
+	// #nosec G115
 	if m < uint64(maxUint) {
 		maxUint = int64(m)
 	}
@@ -1010,7 +1116,7 @@ func (d *decoder) unmarshalInteger(value *unstable.Node, v reflect.Value) error
 	case reflect.Interface:
 		r = reflect.ValueOf(i)
 	default:
-		return unstable.NewParserError(d.p.Raw(value.Raw), d.typeMismatchString("integer", v.Type()))
+		return unstable.NewParserError(d.p.Raw(value.Raw), "%s", d.typeMismatchString("integer", v.Type()))
 	}

 	if !r.Type().AssignableTo(v.Type()) {
@@ -1029,7 +1135,7 @@ func (d *decoder) unmarshalString(value *unstable.Node, v reflect.Value) error {
 	case reflect.Interface:
 		v.Set(reflect.ValueOf(string(value.Data)))
 	default:
-		return unstable.NewParserError(d.p.Raw(value.Raw), d.typeMismatchString("string", v.Type()))
+		return unstable.NewParserError(d.p.Raw(value.Raw), "%s", d.typeMismatchString("string", v.Type()))
 	}

 	return nil
@@ -1080,35 +1186,39 @@ func (d *decoder) keyFromData(keyType reflect.Type, data []byte) (reflect.Value,
 			return reflect.Value{}, fmt.Errorf("toml: error unmarshalling key type %s from text: %w", stringType, err)
 		}
 		return mk.Elem(), nil
+	}

-	case keyType.Kind() == reflect.Int || keyType.Kind() == reflect.Int8 || keyType.Kind() == reflect.Int16 || keyType.Kind() == reflect.Int32 || keyType.Kind() == reflect.Int64:
+	switch keyType.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
 		key, err := strconv.ParseInt(string(data), 10, 64)
 		if err != nil {
 			return reflect.Value{}, fmt.Errorf("toml: error parsing key of type %s from integer: %w", stringType, err)
 		}
 		return reflect.ValueOf(key).Convert(keyType), nil
-	case keyType.Kind() == reflect.Uint || keyType.Kind() == reflect.Uint8 || keyType.Kind() == reflect.Uint16 || keyType.Kind() == reflect.Uint32 || keyType.Kind() == reflect.Uint64:
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
 		key, err := strconv.ParseUint(string(data), 10, 64)
 		if err != nil {
 			return reflect.Value{}, fmt.Errorf("toml: error parsing key of type %s from unsigned integer: %w", stringType, err)
 		}
 		return reflect.ValueOf(key).Convert(keyType), nil

-	case keyType.Kind() == reflect.Float32:
+	case reflect.Float32:
 		key, err := strconv.ParseFloat(string(data), 32)
 		if err != nil {
 			return reflect.Value{}, fmt.Errorf("toml: error parsing key of type %s from float: %w", stringType, err)
 		}
 		return reflect.ValueOf(float32(key)), nil

-	case keyType.Kind() == reflect.Float64:
+	case reflect.Float64:
 		key, err := strconv.ParseFloat(string(data), 64)
 		if err != nil {
 			return reflect.Value{}, fmt.Errorf("toml: error parsing key of type %s from float: %w", stringType, err)
 		}
 		return reflect.ValueOf(float64(key)), nil
+
+	default:
+		return reflect.Value{}, fmt.Errorf("toml: cannot convert map key of type %s to expected type %s", stringType, keyType)
 	}
-	return reflect.Value{}, fmt.Errorf("toml: cannot convert map key of type %s to expected type %s", stringType, keyType)
 }

 func (d *decoder) handleKeyValuePart(key unstable.Iterator, value *unstable.Node, v reflect.Value) (reflect.Value, error) {
@@ -1154,6 +1264,18 @@ func (d *decoder) handleKeyValuePart(key unstable.Iterator, value *unstable.Node
 	case reflect.Struct:
 		path, found := structFieldPath(v, string(key.Node().Data))
 		if !found {
+			// If no matching struct field is found but the target implements the
+			// unstable.Unmarshaler interface (and it is enabled), delegate the
+			// decoding of this value to the custom unmarshaler.
+			if d.unmarshalerInterface {
+				if v.CanAddr() && v.Addr().CanInterface() {
+					if outi, ok := v.Addr().Interface().(unstable.Unmarshaler); ok {
+						// Pass raw bytes from the original document
+						return reflect.Value{}, outi.UnmarshalTOML(d.p.Raw(value.Raw))
+					}
+				}
+			}
+			// Otherwise, keep previous behavior and skip until the next table.
 			d.skipUntilTable = true
 			break
 		}
@@ -1259,13 +1381,13 @@ func fieldByIndex(v reflect.Value, path []int) reflect.Value {

 type fieldPathsMap = map[string][]int

-var globalFieldPathsCache atomic.Value // map[danger.TypeID]fieldPathsMap
+var globalFieldPathsCache atomic.Value // map[reflect.Type]fieldPathsMap

 func structFieldPath(v reflect.Value, name string) ([]int, bool) {
 	t := v.Type()

-	cache, _ := globalFieldPathsCache.Load().(map[danger.TypeID]fieldPathsMap)
-	fieldPaths, ok := cache[danger.MakeTypeID(t)]
+	cache, _ := globalFieldPathsCache.Load().(map[reflect.Type]fieldPathsMap)
+	fieldPaths, ok := cache[t]

 	if !ok {
 		fieldPaths = map[string][]int{}
@@ -1276,8 +1398,8 @@ func structFieldPath(v reflect.Value, name string) ([]int, bool) {
 			fieldPaths[strings.ToLower(name)] = path
 		})

-		newCache := make(map[danger.TypeID]fieldPathsMap, len(cache)+1)
-		newCache[danger.MakeTypeID(t)] = fieldPaths
+		newCache := make(map[reflect.Type]fieldPathsMap, len(cache)+1)
+		newCache[t] = fieldPaths
 		for k, v := range cache {
 			newCache[k] = v
 		}
@@ -1301,7 +1423,9 @@ func forEachField(t reflect.Type, path []int, do func(name string, path []int))
 			continue
 		}

-		fieldPath := append(path, i)
+		fieldPath := make([]int, 0, len(path)+1)
+		fieldPath = append(fieldPath, path...)
+		fieldPath = append(fieldPath, i)
 		fieldPath = fieldPath[:len(fieldPath):len(fieldPath)]

 		name := f.Tag.Get("toml")
@@ -1,10 +1,8 @@
 package unstable

 import (
+	"errors"
 	"fmt"
-	"unsafe"
-
-	"github.com/pelletier/go-toml/v2/internal/danger"
 )

 // Iterator over a sequence of nodes.
@@ -19,30 +17,43 @@ import (
 //		// do something with n
 //	}
 type Iterator struct {
+	nodes   *[]Node
+	idx     int32
 	started bool
-	node    *Node
 }

 // Next moves the iterator forward and returns true if points to a
 // node, false otherwise.
 func (c *Iterator) Next() bool {
+	if c.nodes == nil {
+		return false
+	}
+	nodes := *c.nodes
 	if !c.started {
 		c.started = true
-	} else if c.node.Valid() {
-		c.node = c.node.Next()
+	} else {
+		idx := c.idx
+		if idx >= 0 && int(idx) < len(nodes) {
+			c.idx = nodes[idx].next
+		}
 	}
-	return c.node.Valid()
+	return c.idx >= 0 && int(c.idx) < len(nodes)
 }

 // IsLast returns true if the current node of the iterator is the last
 // one.  Subsequent calls to Next() will return false.
 func (c *Iterator) IsLast() bool {
-	return c.node.next == 0
+	return c.nodes == nil || c.idx < 0 || (*c.nodes)[c.idx].next < 0
 }

 // Node returns a pointer to the node pointed at by the iterator.
 func (c *Iterator) Node() *Node {
-	return c.node
+	if c.nodes == nil || c.idx < 0 {
+		return nil
+	}
+	n := &(*c.nodes)[c.idx]
+	n.nodes = c.nodes
+	return n
 }

 // Node in a TOML expression AST.
@@ -65,11 +76,12 @@ type Node struct {
 	Raw  Range  // Raw bytes from the input.
 	Data []byte // Node value (either allocated or referencing the input).

-	// References to other nodes, as offsets in the backing array
-	// from this node. References can go backward, so those can be
-	// negative.
-	next  int // 0 if last element
-	child int // 0 if no child
+	// Absolute indices into the backing nodes slice. -1 means none.
+	next  int32
+	child int32
+
+	// Reference to the backing nodes slice for navigation.
+	nodes *[]Node
 }

 // Range of bytes in the document.
@@ -80,24 +92,24 @@ type Range struct {

 // Next returns a pointer to the next node, or nil if there is no next node.
 func (n *Node) Next() *Node {
-	if n.next == 0 {
+	if n.next < 0 {
 		return nil
 	}
-	ptr := unsafe.Pointer(n)
-	size := unsafe.Sizeof(Node{})
-	return (*Node)(danger.Stride(ptr, size, n.next))
+	next := &(*n.nodes)[n.next]
+	next.nodes = n.nodes
+	return next
 }

 // Child returns a pointer to the first child node of this node. Other children
-// can be accessed calling Next on the first child.  Returns an nil if this Node
+// can be accessed calling Next on the first child.  Returns nil if this Node
 // has no child.
 func (n *Node) Child() *Node {
-	if n.child == 0 {
+	if n.child < 0 {
 		return nil
 	}
-	ptr := unsafe.Pointer(n)
-	size := unsafe.Sizeof(Node{})
-	return (*Node)(danger.Stride(ptr, size, n.child))
+	child := &(*n.nodes)[n.child]
+	child.nodes = n.nodes
+	return child
 }

 // Valid returns true if the node's kind is set (not to Invalid).
@@ -111,13 +123,14 @@ func (n *Node) Valid() bool {
 func (n *Node) Key() Iterator {
 	switch n.Kind {
 	case KeyValue:
-		value := n.Child()
-		if !value.Valid() {
-			panic(fmt.Errorf("KeyValue should have at least two children"))
+		child := n.child
+		if child < 0 {
+			panic(errors.New("KeyValue should have at least two children"))
 		}
-		return Iterator{node: value.Next()}
+		valueNode := &(*n.nodes)[child]
+		return Iterator{nodes: n.nodes, idx: valueNode.next}
 	case Table, ArrayTable:
-		return Iterator{node: n.Child()}
+		return Iterator{nodes: n.nodes, idx: n.child}
 	default:
 		panic(fmt.Errorf("Key() is not supported on a %s", n.Kind))
 	}
@@ -132,5 +145,5 @@ func (n *Node) Value() *Node {

 // Children returns an iterator over a node's children.
 func (n *Node) Children() Iterator {
-	return Iterator{node: n.Child()}
+	return Iterator{nodes: n.nodes, idx: n.child}
 }
@@ -7,15 +7,6 @@ type root struct {
 	nodes []Node
 }

-// Iterator over the top level nodes.
-func (r *root) Iterator() Iterator {
-	it := Iterator{}
-	if len(r.nodes) > 0 {
-		it.node = &r.nodes[0]
-	}
-	return it
-}
-
 func (r *root) at(idx reference) *Node {
 	return &r.nodes[idx]
 }
@@ -33,12 +24,10 @@ type builder struct {
 	lastIdx int
 }

-func (b *builder) Tree() *root {
-	return &b.tree
-}
-
 func (b *builder) NodeAt(ref reference) *Node {
-	return b.tree.at(ref)
+	n := b.tree.at(ref)
+	n.nodes = &b.tree.nodes
+	return n
 }

 func (b *builder) Reset() {
@@ -48,24 +37,28 @@ func (b *builder) Reset() {

 func (b *builder) Push(n Node) reference {
 	b.lastIdx = len(b.tree.nodes)
+	n.next = -1
+	n.child = -1
 	b.tree.nodes = append(b.tree.nodes, n)
 	return reference(b.lastIdx)
 }

 func (b *builder) PushAndChain(n Node) reference {
 	newIdx := len(b.tree.nodes)
+	n.next = -1
+	n.child = -1
 	b.tree.nodes = append(b.tree.nodes, n)
 	if b.lastIdx >= 0 {
-		b.tree.nodes[b.lastIdx].next = newIdx - b.lastIdx
+		b.tree.nodes[b.lastIdx].next = int32(newIdx) //nolint:gosec // TOML ASTs are small
 	}
 	b.lastIdx = newIdx
 	return reference(b.lastIdx)
 }

 func (b *builder) AttachChild(parent reference, child reference) {
-	b.tree.nodes[parent].child = int(child) - int(parent)
+	b.tree.nodes[parent].child = int32(child) //nolint:gosec // TOML ASTs are small
 }

 func (b *builder) Chain(from reference, to reference) {
-	b.tree.nodes[from].next = int(to) - int(from)
+	b.tree.nodes[from].next = int32(to) //nolint:gosec // TOML ASTs are small
 }
@@ -6,28 +6,40 @@ import "fmt"
 type Kind int

 const (
-	// Meta
+	// Invalid represents an invalid meta node.
 	Invalid Kind = iota
+	// Comment represents a comment meta node.
 	Comment
+	// Key represents a key meta node.
 	Key

-	// Top level structures
+	// Table represents a top-level table.
 	Table
+	// ArrayTable represents a top-level array table.
 	ArrayTable
+	// KeyValue represents a top-level key value.
 	KeyValue

-	// Containers values
+	// Array represents an array container value.
 	Array
+	// InlineTable represents an inline table container value.
 	InlineTable

-	// Values
+	// String represents a string value.
 	String
+	// Bool represents a boolean value.
 	Bool
+	// Float represents a floating point value.
 	Float
+	// Integer represents an integer value.
 	Integer
+	// LocalDate represents a a local date value.
 	LocalDate
+	// LocalTime represents a local time value.
 	LocalTime
+	// LocalDateTime represents a local date/time value.
 	LocalDateTime
+	// DateTime represents a data/time value.
 	DateTime
 )

@@ -6,7 +6,6 @@ import (
 	"unicode"

 	"github.com/pelletier/go-toml/v2/internal/characters"
-	"github.com/pelletier/go-toml/v2/internal/danger"
 )

 // ParserError describes an error relative to the content of the document.
@@ -70,11 +69,26 @@ func (p *Parser) Data() []byte {
 // panics.
 func (p *Parser) Range(b []byte) Range {
 	return Range{
-		Offset: uint32(danger.SubsliceOffset(p.data, b)),
-		Length: uint32(len(b)),
+		Offset: uint32(p.subsliceOffset(b)), //nolint:gosec // TOML documents are small
+		Length: uint32(len(b)),              //nolint:gosec // TOML documents are small
 	}
 }

+// rangeOfToken computes the Range of a token given the remaining bytes after the token.
+// This is used when the token was extracted from the beginning of some position,
+// and 'rest' is what remains after the token.
+func (p *Parser) rangeOfToken(token, rest []byte) Range {
+	offset := len(p.data) - len(token) - len(rest)
+	return Range{Offset: uint32(offset), Length: uint32(len(token))} //nolint:gosec // TOML documents are small
+}
+
+// subsliceOffset returns the byte offset of subslice b within p.data.
+// b must be a suffix (tail) of p.data.
+func (p *Parser) subsliceOffset(b []byte) int {
+	// b is a suffix of p.data, so its offset is len(p.data) - len(b)
+	return len(p.data) - len(b)
+}
+
 // Raw returns the slice corresponding to the bytes in the given range.
 func (p *Parser) Raw(raw Range) []byte {
 	return p.data[raw.Offset : raw.Offset+raw.Length]
@@ -158,9 +172,17 @@ type Shape struct {
 	End   Position
 }

-func (p *Parser) position(b []byte) Position {
-	offset := danger.SubsliceOffset(p.data, b)
+// Shape returns the shape of the given range in the input.  Will
+// panic if the range is not a subslice of the input.
+func (p *Parser) Shape(r Range) Shape {
+	return Shape{
+		Start: p.positionAt(int(r.Offset)),
+		End:   p.positionAt(int(r.Offset + r.Length)),
+	}
+}

+// positionAt returns the position at the given byte offset in the document.
+func (p *Parser) positionAt(offset int) Position {
 	lead := p.data[:offset]

 	return Position{
@@ -170,16 +192,6 @@ func (p *Parser) position(b []byte) Position {
 	}
 }

-// Shape returns the shape of the given range in the input.  Will
-// panic if the range is not a subslice of the input.
-func (p *Parser) Shape(r Range) Shape {
-	raw := p.Raw(r)
-	return Shape{
-		Start: p.position(raw),
-		End:   p.position(raw[r.Length:]),
-	}
-}
-
 func (p *Parser) parseNewline(b []byte) ([]byte, error) {
 	if b[0] == '\n' {
 		return b[1:], nil
@@ -199,7 +211,7 @@ func (p *Parser) parseComment(b []byte) (reference, []byte, error) {
 	if p.KeepComments && err == nil {
 		ref = p.builder.Push(Node{
 			Kind: Comment,
-			Raw:  p.Range(data),
+			Raw:  p.rangeOfToken(data, rest),
 			Data: data,
 		})
 	}
@@ -316,6 +328,9 @@ func (p *Parser) parseStdTable(b []byte) (reference, []byte, error) {

 func (p *Parser) parseKeyval(b []byte) (reference, []byte, error) {
 	// keyval = key keyval-sep val
+	// Track the start position for Raw range
+	startB := b
+
 	ref := p.builder.Push(Node{
 		Kind: KeyValue,
 	})
@@ -330,7 +345,7 @@ func (p *Parser) parseKeyval(b []byte) (reference, []byte, error) {
 	b = p.parseWhitespace(b)

 	if len(b) == 0 {
-		return invalidReference, nil, NewParserError(b, "expected = after a key, but the document ends there")
+		return invalidReference, nil, NewParserError(startB[:len(startB)-len(b)], "expected = after a key, but the document ends there")
 	}

 	b, err = expect('=', b)
@@ -348,6 +363,11 @@ func (p *Parser) parseKeyval(b []byte) (reference, []byte, error) {
 	p.builder.Chain(valRef, key)
 	p.builder.AttachChild(ref, valRef)

+	// Set Raw to span the entire key-value expression.
+	// Access the node directly in the slice to avoid the write barrier
+	// that NodeAt's nodes-pointer setup would trigger.
+	p.builder.tree.nodes[ref].Raw = p.rangeOfToken(startB[:len(startB)-len(b)], b)
+
 	return ref, b, err
 }

@@ -376,7 +396,7 @@ func (p *Parser) parseVal(b []byte) (reference, []byte, error) {
 		if err == nil {
 			ref = p.builder.Push(Node{
 				Kind: String,
-				Raw:  p.Range(raw),
+				Raw:  p.rangeOfToken(raw, b),
 				Data: v,
 			})
 		}
@@ -394,7 +414,7 @@ func (p *Parser) parseVal(b []byte) (reference, []byte, error) {
 		if err == nil {
 			ref = p.builder.Push(Node{
 				Kind: String,
-				Raw:  p.Range(raw),
+				Raw:  p.rangeOfToken(raw, b),
 				Data: v,
 			})
 		}
@@ -456,7 +476,7 @@ func (p *Parser) parseInlineTable(b []byte) (reference, []byte, error) {
 	// inline-table-keyvals = keyval [ inline-table-sep inline-table-keyvals ]
 	parent := p.builder.Push(Node{
 		Kind: InlineTable,
-		Raw:  p.Range(b[:1]),
+		Raw:  p.rangeOfToken(b[:1], b[1:]),
 	})

 	first := true
@@ -542,7 +562,7 @@ func (p *Parser) parseValArray(b []byte) (reference, []byte, error) {

 	var err error
 	for len(b) > 0 {
-		cref := invalidReference
+		var cref reference
 		cref, b, err = p.parseOptionalWhitespaceCommentNewline(b)
 		if err != nil {
 			return parent, nil, err
@@ -611,12 +631,13 @@ func (p *Parser) parseOptionalWhitespaceCommentNewline(b []byte) (reference, []b
 	latestCommentRef := invalidReference

 	addComment := func(ref reference) {
-		if rootCommentRef == invalidReference {
+		switch {
+		case rootCommentRef == invalidReference:
 			rootCommentRef = ref
-		} else if latestCommentRef == invalidReference {
+		case latestCommentRef == invalidReference:
 			p.builder.AttachChild(rootCommentRef, ref)
 			latestCommentRef = ref
-		} else {
+		default:
 			p.builder.Chain(latestCommentRef, ref)
 			latestCommentRef = ref
 		}
@@ -704,11 +725,11 @@ func (p *Parser) parseMultilineBasicString(b []byte) ([]byte, []byte, []byte, er

 	if !escaped {
 		str := token[startIdx:endIdx]
-		verr := characters.Utf8TomlValidAlreadyEscaped(str)
-		if verr.Zero() {
+		highlight := characters.Utf8TomlValidAlreadyEscaped(str)
+		if len(highlight) == 0 {
 			return token, str, rest, nil
 		}
-		return nil, nil, nil, NewParserError(str[verr.Index:verr.Index+verr.Size], "invalid UTF-8")
+		return nil, nil, nil, NewParserError(highlight, "invalid UTF-8")
 	}

 	var builder bytes.Buffer
@@ -744,7 +765,7 @@ func (p *Parser) parseMultilineBasicString(b []byte) ([]byte, []byte, []byte, er
 				i += j
 				for ; i < len(token)-3; i++ {
 					c := token[i]
-					if !(c == '\n' || c == '\r' || c == ' ' || c == '\t') {
+					if c != '\n' && c != '\r' && c != ' ' && c != '\t' {
 						i--
 						break
 					}
@@ -820,7 +841,7 @@ func (p *Parser) parseKey(b []byte) (reference, []byte, error) {

 	ref := p.builder.Push(Node{
 		Kind: Key,
-		Raw:  p.Range(raw),
+		Raw:  p.rangeOfToken(raw, b),
 		Data: key,
 	})

@@ -836,7 +857,7 @@ func (p *Parser) parseKey(b []byte) (reference, []byte, error) {

 			p.builder.PushAndChain(Node{
 				Kind: Key,
-				Raw:  p.Range(raw),
+				Raw:  p.rangeOfToken(raw, b),
 				Data: key,
 			})
 		} else {
@@ -897,11 +918,11 @@ func (p *Parser) parseBasicString(b []byte) ([]byte, []byte, []byte, error) {
 	// validate the string and return a direct reference to the buffer.
 	if !escaped {
 		str := token[startIdx:endIdx]
-		verr := characters.Utf8TomlValidAlreadyEscaped(str)
-		if verr.Zero() {
+		highlight := characters.Utf8TomlValidAlreadyEscaped(str)
+		if len(highlight) == 0 {
 			return token, str, rest, nil
 		}
-		return nil, nil, nil, NewParserError(str[verr.Index:verr.Index+verr.Size], "invalid UTF-8")
+		return nil, nil, nil, NewParserError(highlight, "invalid UTF-8")
 	}

 	i := startIdx
@@ -972,7 +993,7 @@ func hexToRune(b []byte, length int) (rune, error) {

 	var r uint32
 	for i, c := range b {
-		d := uint32(0)
+		var d uint32
 		switch {
 		case '0' <= c && c <= '9':
 			d = uint32(c - '0')
@@ -1013,7 +1034,7 @@ func (p *Parser) parseIntOrFloatOrDateTime(b []byte) (reference, []byte, error)
 		return p.builder.Push(Node{
 			Kind: Float,
 			Data: b[:3],
-			Raw:  p.Range(b[:3]),
+			Raw:  p.rangeOfToken(b[:3], b[3:]),
 		}), b[3:], nil
 	case 'n':
 		if !scanFollowsNan(b) {
@@ -1023,7 +1044,7 @@ func (p *Parser) parseIntOrFloatOrDateTime(b []byte) (reference, []byte, error)
 		return p.builder.Push(Node{
 			Kind: Float,
 			Data: b[:3],
-			Raw:  p.Range(b[:3]),
+			Raw:  p.rangeOfToken(b[:3], b[3:]),
 		}), b[3:], nil
 	case '+', '-':
 		return p.scanIntOrFloat(b)
@@ -1076,7 +1097,7 @@ byteLoop:
 			}
 		case c == 'T' || c == 't' || c == ':' || c == '.':
 			hasTime = true
-		case c == '+' || c == '-' || c == 'Z' || c == 'z':
+		case c == '+' || c == 'Z' || c == 'z':
 			hasTz = true
 		case c == ' ':
 			if !seenSpace && i+1 < len(b) && isDigit(b[i+1]) {
@@ -1148,7 +1169,7 @@ func (p *Parser) scanIntOrFloat(b []byte) (reference, []byte, error) {
 		return p.builder.Push(Node{
 			Kind: Integer,
 			Data: b[:i],
-			Raw:  p.Range(b[:i]),
+			Raw:  p.rangeOfToken(b[:i], b[i:]),
 		}), b[i:], nil
 	}

@@ -1172,7 +1193,7 @@ func (p *Parser) scanIntOrFloat(b []byte) (reference, []byte, error) {
 				return p.builder.Push(Node{
 					Kind: Float,
 					Data: b[:i+3],
-					Raw:  p.Range(b[:i+3]),
+					Raw:  p.rangeOfToken(b[:i+3], b[i+3:]),
 				}), b[i+3:], nil
 			}

@@ -1184,7 +1205,7 @@ func (p *Parser) scanIntOrFloat(b []byte) (reference, []byte, error) {
 				return p.builder.Push(Node{
 					Kind: Float,
 					Data: b[:i+3],
-					Raw:  p.Range(b[:i+3]),
+					Raw:  p.rangeOfToken(b[:i+3], b[i+3:]),
 				}), b[i+3:], nil
 			}

@@ -1207,7 +1228,7 @@ func (p *Parser) scanIntOrFloat(b []byte) (reference, []byte, error) {
 	return p.builder.Push(Node{
 		Kind: kind,
 		Data: b[:i],
-		Raw:  p.Range(b[:i]),
+		Raw:  p.rangeOfToken(b[:i], b[i:]),
 	}), b[i:], nil
 }

@@ -1,7 +1,32 @@
 package unstable

-// The Unmarshaler interface may be implemented by types to customize their
-// behavior when being unmarshaled from a TOML document.
+// Unmarshaler is implemented by types that can unmarshal a TOML
+// description of themselves. The input is a valid TOML document
+// containing the relevant portion of the parsed document.
+//
+// For tables (including split tables defined in multiple places),
+// the data contains the raw key-value bytes from the original document
+// with adjusted table headers to be relative to the unmarshaling target.
 type Unmarshaler interface {
-	UnmarshalTOML(value *Node) error
+	UnmarshalTOML(data []byte) error
+}
+
+// RawMessage is a raw encoded TOML value. It implements Unmarshaler
+// and can be used to delay TOML decoding or capture raw content.
+//
+// Example usage:
+//
+//	type Config struct {
+//	    Plugin RawMessage `toml:"plugin"`
+//	}
+//
+//	var cfg Config
+//	toml.NewDecoder(r).EnableUnmarshalerInterface().Decode(&cfg)
+//	// cfg.Plugin now contains the raw TOML bytes for [plugin]
+type RawMessage []byte
+
+// UnmarshalTOML implements Unmarshaler.
+func (m *RawMessage) UnmarshalTOML(data []byte) error {
+	*m = append((*m)[0:0], data...)
+	return nil
 }
@@ -1,27 +0,0 @@
-Copyright 2009 The Go Authors.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-   * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-   * Neither the name of Google LLC nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
@@ -1,22 +0,0 @@
-Additional IP Rights Grant (Patents)
-
-"This implementation" means the copyrightable works distributed by
-Google as part of the Go project.
-
-Google hereby grants to You a perpetual, worldwide, non-exclusive,
-no-charge, royalty-free, irrevocable (except as stated in this section)
-patent license to make, have made, use, offer to sell, sell, import,
-transfer and otherwise run, modify and propagate the contents of this
-implementation of Go, where such license applies only to those patent
-claims, both currently owned or controlled by Google and acquired in
-the future, licensable by Google that are necessarily infringed by this
-implementation of Go.  This grant does not include claims that would be
-infringed only as a consequence of further modification of this
-implementation.  If you or your agent or exclusive licensee institute or
-order or agree to the institution of patent litigation against any
-entity (including a cross-claim or counterclaim in a lawsuit) alleging
-that this implementation of Go or any code incorporated within this
-implementation of Go constitutes direct or contributory patent
-infringement, or inducement of patent infringement, then any patent
-rights granted to you under this License for this implementation of Go
-shall terminate as of the date such litigation is filed.
@@ -1,54 +0,0 @@
-// Copyright 2021 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package constraints defines a set of useful constraints to be used
-// with type parameters.
-package constraints
-
-import "cmp"
-
-// Signed is a constraint that permits any signed integer type.
-// If future releases of Go add new predeclared signed integer types,
-// this constraint will be modified to include them.
-type Signed interface {
-	~int | ~int8 | ~int16 | ~int32 | ~int64
-}
-
-// Unsigned is a constraint that permits any unsigned integer type.
-// If future releases of Go add new predeclared unsigned integer types,
-// this constraint will be modified to include them.
-type Unsigned interface {
-	~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr
-}
-
-// Integer is a constraint that permits any integer type.
-// If future releases of Go add new predeclared integer types,
-// this constraint will be modified to include them.
-type Integer interface {
-	Signed | Unsigned
-}
-
-// Float is a constraint that permits any floating-point type.
-// If future releases of Go add new predeclared floating-point types,
-// this constraint will be modified to include them.
-type Float interface {
-	~float32 | ~float64
-}
-
-// Complex is a constraint that permits any complex numeric type.
-// If future releases of Go add new predeclared complex numeric types,
-// this constraint will be modified to include them.
-type Complex interface {
-	~complex64 | ~complex128
-}
-
-// Ordered is a constraint that permits any ordered type: any type
-// that supports the operators < <= >= >.
-// If future releases of Go add new ordered types,
-// this constraint will be modified to include them.
-//
-// This type is redundant since Go 1.21 introduced [cmp.Ordered].
-//
-//go:fix inline
-type Ordered = cmp.Ordered
@@ -33,17 +33,21 @@ guidelines, there may be valid reasons to do so, but it should be rare.

 ## Guidelines for Pull Requests

-How to get your contributions merged smoothly and quickly:
+Please read the following carefully to ensure your contributions can be merged
+smoothly and quickly.
+
+### PR Contents

 - Create **small PRs** that are narrowly focused on **addressing a single
  concern**. We often receive PRs that attempt to fix several things at the same
  time, and if one part of the PR has a problem, that will hold up the entire
  PR.

- For **speculative changes**, consider opening an issue and discussing it
-  first. If you are suggesting a behavioral or API change, consider starting
-  with a [gRFC proposal](https://github.com/grpc/proposal). Many new features
-  that are not bug fixes will require cross-language agreement.
+- If your change does not address an **open issue** with an **agreed
+  resolution**, consider opening an issue and discussing it first. If you are
+  suggesting a behavioral or API change, consider starting with a [gRFC
+  proposal](https://github.com/grpc/proposal). Many new features that are not
+  bug fixes will require cross-language agreement.

 - If you want to fix **formatting or style**, consider whether your changes are
  an obvious improvement or might be considered a personal preference. If a
@@ -56,16 +60,6 @@ How to get your contributions merged smoothly and quickly:
  often written as "iff". Please do not make spelling correction changes unless
  you are certain they are misspellings.

- Provide a good **PR description** as a record of **what** change is being made
-  and **why** it was made. Link to a GitHub issue if it exists.
-
- Maintain a **clean commit history** and use **meaningful commit messages**.
-  PRs with messy commit histories are difficult to review and won't be merged.
-  Before sending your PR, ensure your changes are based on top of the latest
-  `upstream/master` commits, and avoid rebasing in the middle of a code review.
-  You should **never use `git push -f`** unless absolutely necessary during a
-  review, as it can interfere with GitHub's tracking of comments.
-
 - **All tests need to be passing** before your change can be merged. We
  recommend you run tests locally before creating your PR to catch breakages
  early on:
@@ -81,15 +75,80 @@ How to get your contributions merged smoothly and quickly:
  GitHub, which will trigger a GitHub Actions run that you can use to verify
  everything is passing.

- If you are adding a new file, make sure it has the **copyright message**
+- Note that there are two GitHub actions checks that need not be green:
+
+  1. We test the freshness of the generated proto code we maintain via the
+     `vet-proto` check. If the source proto files are updated, but our repo is
+     not updated, an optional checker will fail. This will be fixed by our team
+     in a separate PR and will not prevent the merge of your PR.
+
+  2. We run a checker that will fail if there is any change in dependencies of
+     an exported package via the `dependencies` check. If new dependencies are
+     added that are not appropriate, we may not accept your PR (see below).
+
+- If you are adding a **new file**, make sure it has the **copyright message**
  template at the top as a comment. You can copy the message from an existing
  file and update the year.

 - The grpc package should only depend on standard Go packages and a small number
  of exceptions. **If your contribution introduces new dependencies**, you will
-  need a discussion with gRPC-Go maintainers. A GitHub action check will run on
-  every PR, and will flag any transitive dependency changes from any public
-  package.
+  need a discussion with gRPC-Go maintainers.
+
+### PR Descriptions
+
+- **PR titles** should start with the name of the component being addressed, or
+  the type of change. Examples: transport, client, server, round_robin, xds,
+  cleanup, deps.
+
+- Read and follow the **guidelines for PR titles and descriptions** here:
+  https://google.github.io/eng-practices/review/developer/cl-descriptions.html
+
+  *particularly* the sections "First Line" and "Body is Informative".
+
+  Note: your PR description will be used as the git commit message in a
+  squash-and-merge if your PR is approved. We may make changes to this as
+  necessary.
+
+- **Does this PR relate to an open issue?** On the first line, please use the
+  tag `Fixes #<issue>` to ensure the issue is closed when the PR is merged. Or
+  use `Updates #<issue>` if the PR is related to an open issue, but does not fix
+  it. Consider filing an issue if one does not already exist.
+
+- PR descriptions *must* conclude with **release notes** as follows:
+
+  ```
+  RELEASE NOTES:
+  * <component>: <summary>
+  ```
+
+  This need not match the PR title.
+
+  The summary must:
+
+  * be something that gRPC users will understand.
+
+  * clearly explain the feature being added, the issue being fixed, or the
+    behavior being changed, etc. If fixing a bug, be clear about how the bug
+    can be triggered by an end-user.
+
+  * begin with a capital letter and use complete sentences.
+
+  * be as short as possible to describe the change being made.
+
+  If a PR is *not* end-user visible -- e.g. a cleanup, testing change, or
+  GitHub-related, use `RELEASE NOTES: n/a`.
+
+### PR Process
+
+- Please **self-review** your code changes before sending your PR. This will
+  prevent simple, obvious errors from causing delays.
+
+- Maintain a **clean commit history** and use **meaningful commit messages**.
+  PRs with messy commit histories are difficult to review and won't be merged.
+  Before sending your PR, ensure your changes are based on top of the latest
+  `upstream/master` commits, and avoid rebasing in the middle of a code review.
+  You should **never use `git push -f`** unless absolutely necessary during a
+  review, as it can interfere with GitHub's tracking of comments.

 - Unless your PR is trivial, you should **expect reviewer comments** that you
  will need to address before merging. We'll label the PR as `Status: Requires
@@ -98,5 +157,3 @@ How to get your contributions merged smoothly and quickly:
  `stale`, and we will automatically close it after 7 days if we don't hear back
  from you. Please feel free to ping issues or bugs if you do not get a response
  within a week.
-
- Exceptions to the rules can be made if there's a compelling reason to do so.
@@ -9,21 +9,19 @@ for general contribution guidelines.

 ## Maintainers (in alphabetical order)

- [aranjans](https://github.com/aranjans), Google LLC
 - [arjan-bal](https://github.com/arjan-bal), Google LLC
 - [arvindbr8](https://github.com/arvindbr8), Google LLC
 - [atollena](https://github.com/atollena), Datadog, Inc.
 - [dfawley](https://github.com/dfawley), Google LLC
 - [easwars](https://github.com/easwars), Google LLC
- [erm-g](https://github.com/erm-g), Google LLC
 - [gtcooke94](https://github.com/gtcooke94), Google LLC
- [purnesh42h](https://github.com/purnesh42h), Google LLC
- [zasweq](https://github.com/zasweq), Google LLC

 ## Emeritus Maintainers (in alphabetical order)
 - [adelez](https://github.com/adelez)
+- [aranjans](https://github.com/aranjans)
 - [canguler](https://github.com/canguler)
 - [cesarghali](https://github.com/cesarghali)
+- [erm-g](https://github.com/erm-g)
 - [iamqizhao](https://github.com/iamqizhao)
 - [jeanbza](https://github.com/jeanbza)
 - [jtattermusch](https://github.com/jtattermusch)
@@ -32,5 +30,7 @@ for general contribution guidelines.
 - [matt-kwong](https://github.com/matt-kwong)
 - [menghanl](https://github.com/menghanl)
 - [nicolasnoble](https://github.com/nicolasnoble)
+- [purnesh42h](https://github.com/purnesh42h)
 - [srini100](https://github.com/srini100)
 - [yongni](https://github.com/yongni)
+- [zasweq](https://github.com/zasweq)
@@ -75,8 +75,6 @@ func unregisterForTesting(name string) {

 func init() {
 	internal.BalancerUnregister = unregisterForTesting
-	internal.ConnectedAddress = connectedAddress
-	internal.SetConnectedAddress = setConnectedAddress
 }

 // Get returns the resolver builder registered with the given name.
@@ -37,6 +37,8 @@ import (
 	"google.golang.org/grpc/resolver"
 )

+var randIntN = rand.IntN
+
 // ChildState is the balancer state of a child along with the endpoint which
 // identifies the child balancer.
 type ChildState struct {
@@ -112,6 +114,21 @@ type endpointSharding struct {
 	mu sync.Mutex
 }

+// rotateEndpoints returns a slice of all the input endpoints rotated a random
+// amount.
+func rotateEndpoints(es []resolver.Endpoint) []resolver.Endpoint {
+	les := len(es)
+	if les == 0 {
+		return es
+	}
+	r := randIntN(les)
+	// Make a copy to avoid mutating data beyond the end of es.
+	ret := make([]resolver.Endpoint, les)
+	copy(ret, es[r:])
+	copy(ret[les-r:], es[:r])
+	return ret
+}
+
 // UpdateClientConnState creates a child for new endpoints and deletes children
 // for endpoints that are no longer present. It also updates all the children,
 // and sends a single synchronous update of the childrens' aggregated state at
@@ -133,7 +150,7 @@ func (es *endpointSharding) UpdateClientConnState(state balancer.ClientConnState
 	newChildren := resolver.NewEndpointMap[*balancerWrapper]()

 	// Update/Create new children.
-	for _, endpoint := range state.ResolverState.Endpoints {
+	for _, endpoint := range rotateEndpoints(state.ResolverState.Endpoints) {
 		if _, ok := newChildren.Get(endpoint); ok {
 			// Endpoint child was already created, continue to avoid duplicate
 			// update.
@@ -279,7 +296,7 @@ func (es *endpointSharding) updateState() {
 	p := &pickerWithChildStates{
 		pickers:     pickers,
 		childStates: childStates,
-		next:        uint32(rand.IntN(len(pickers))),
+		next:        uint32(randIntN(len(pickers))),
 	}
 	es.cc.UpdateState(balancer.State{
 		ConnectivityState: aggState,
@@ -26,6 +26,8 @@ import (
 var (
 	// RandShuffle pseudo-randomizes the order of addresses.
 	RandShuffle = rand.Shuffle
+	// RandFloat64 returns, as a float64, a pseudo-random number in [0.0,1.0).
+	RandFloat64 = rand.Float64
 	// TimeAfterFunc allows mocking the timer for testing connection delay
 	// related functionality.
 	TimeAfterFunc = func(d time.Duration, f func()) func() {
@@ -1,906 +0,0 @@
-/*
- *
- * Copyright 2024 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-// Package pickfirstleaf contains the pick_first load balancing policy which
-// will be the universal leaf policy after dualstack changes are implemented.
-//
-// # Experimental
-//
-// Notice: This package is EXPERIMENTAL and may be changed or removed in a
-// later release.
-package pickfirstleaf
-
-import (
-	"encoding/json"
-	"errors"
-	"fmt"
-	"net"
-	"net/netip"
-	"sync"
-	"time"
-
-	"google.golang.org/grpc/balancer"
-	"google.golang.org/grpc/balancer/pickfirst/internal"
-	"google.golang.org/grpc/connectivity"
-	expstats "google.golang.org/grpc/experimental/stats"
-	"google.golang.org/grpc/grpclog"
-	"google.golang.org/grpc/internal/envconfig"
-	internalgrpclog "google.golang.org/grpc/internal/grpclog"
-	"google.golang.org/grpc/internal/pretty"
-	"google.golang.org/grpc/resolver"
-	"google.golang.org/grpc/serviceconfig"
-)
-
-func init() {
-	if envconfig.NewPickFirstEnabled {
-		// Register as the default pick_first balancer.
-		Name = "pick_first"
-	}
-	balancer.Register(pickfirstBuilder{})
-}
-
-// enableHealthListenerKeyType is a unique key type used in resolver
-// attributes to indicate whether the health listener usage is enabled.
-type enableHealthListenerKeyType struct{}
-
-var (
-	logger = grpclog.Component("pick-first-leaf-lb")
-	// Name is the name of the pick_first_leaf balancer.
-	// It is changed to "pick_first" in init() if this balancer is to be
-	// registered as the default pickfirst.
-	Name                 = "pick_first_leaf"
-	disconnectionsMetric = expstats.RegisterInt64Count(expstats.MetricDescriptor{
-		Name:        "grpc.lb.pick_first.disconnections",
-		Description: "EXPERIMENTAL. Number of times the selected subchannel becomes disconnected.",
-		Unit:        "disconnection",
-		Labels:      []string{"grpc.target"},
-		Default:     false,
-	})
-	connectionAttemptsSucceededMetric = expstats.RegisterInt64Count(expstats.MetricDescriptor{
-		Name:        "grpc.lb.pick_first.connection_attempts_succeeded",
-		Description: "EXPERIMENTAL. Number of successful connection attempts.",
-		Unit:        "attempt",
-		Labels:      []string{"grpc.target"},
-		Default:     false,
-	})
-	connectionAttemptsFailedMetric = expstats.RegisterInt64Count(expstats.MetricDescriptor{
-		Name:        "grpc.lb.pick_first.connection_attempts_failed",
-		Description: "EXPERIMENTAL. Number of failed connection attempts.",
-		Unit:        "attempt",
-		Labels:      []string{"grpc.target"},
-		Default:     false,
-	})
-)
-
-const (
-	// TODO: change to pick-first when this becomes the default pick_first policy.
-	logPrefix = "[pick-first-leaf-lb %p] "
-	// connectionDelayInterval is the time to wait for during the happy eyeballs
-	// pass before starting the next connection attempt.
-	connectionDelayInterval = 250 * time.Millisecond
-)
-
-type ipAddrFamily int
-
-const (
-	// ipAddrFamilyUnknown represents strings that can't be parsed as an IP
-	// address.
-	ipAddrFamilyUnknown ipAddrFamily = iota
-	ipAddrFamilyV4
-	ipAddrFamilyV6
-)
-
-type pickfirstBuilder struct{}
-
-func (pickfirstBuilder) Build(cc balancer.ClientConn, bo balancer.BuildOptions) balancer.Balancer {
-	b := &pickfirstBalancer{
-		cc:              cc,
-		target:          bo.Target.String(),
-		metricsRecorder: cc.MetricsRecorder(),
-
-		subConns:              resolver.NewAddressMapV2[*scData](),
-		state:                 connectivity.Connecting,
-		cancelConnectionTimer: func() {},
-	}
-	b.logger = internalgrpclog.NewPrefixLogger(logger, fmt.Sprintf(logPrefix, b))
-	return b
-}
-
-func (b pickfirstBuilder) Name() string {
-	return Name
-}
-
-func (pickfirstBuilder) ParseConfig(js json.RawMessage) (serviceconfig.LoadBalancingConfig, error) {
-	var cfg pfConfig
-	if err := json.Unmarshal(js, &cfg); err != nil {
-		return nil, fmt.Errorf("pickfirst: unable to unmarshal LB policy config: %s, error: %v", string(js), err)
-	}
-	return cfg, nil
-}
-
-// EnableHealthListener updates the state to configure pickfirst for using a
-// generic health listener.
-func EnableHealthListener(state resolver.State) resolver.State {
-	state.Attributes = state.Attributes.WithValue(enableHealthListenerKeyType{}, true)
-	return state
-}
-
-type pfConfig struct {
-	serviceconfig.LoadBalancingConfig `json:"-"`
-
-	// If set to true, instructs the LB policy to shuffle the order of the list
-	// of endpoints received from the name resolver before attempting to
-	// connect to them.
-	ShuffleAddressList bool `json:"shuffleAddressList"`
-}
-
-// scData keeps track of the current state of the subConn.
-// It is not safe for concurrent access.
-type scData struct {
-	// The following fields are initialized at build time and read-only after
-	// that.
-	subConn balancer.SubConn
-	addr    resolver.Address
-
-	rawConnectivityState connectivity.State
-	// The effective connectivity state based on raw connectivity, health state
-	// and after following sticky TransientFailure behaviour defined in A62.
-	effectiveState              connectivity.State
-	lastErr                     error
-	connectionFailedInFirstPass bool
-}
-
-func (b *pickfirstBalancer) newSCData(addr resolver.Address) (*scData, error) {
-	sd := &scData{
-		rawConnectivityState: connectivity.Idle,
-		effectiveState:       connectivity.Idle,
-		addr:                 addr,
-	}
-	sc, err := b.cc.NewSubConn([]resolver.Address{addr}, balancer.NewSubConnOptions{
-		StateListener: func(state balancer.SubConnState) {
-			b.updateSubConnState(sd, state)
-		},
-	})
-	if err != nil {
-		return nil, err
-	}
-	sd.subConn = sc
-	return sd, nil
-}
-
-type pickfirstBalancer struct {
-	// The following fields are initialized at build time and read-only after
-	// that and therefore do not need to be guarded by a mutex.
-	logger          *internalgrpclog.PrefixLogger
-	cc              balancer.ClientConn
-	target          string
-	metricsRecorder expstats.MetricsRecorder // guaranteed to be non nil
-
-	// The mutex is used to ensure synchronization of updates triggered
-	// from the idle picker and the already serialized resolver,
-	// SubConn state updates.
-	mu sync.Mutex
-	// State reported to the channel based on SubConn states and resolver
-	// updates.
-	state connectivity.State
-	// scData for active subonns mapped by address.
-	subConns              *resolver.AddressMapV2[*scData]
-	addressList           addressList
-	firstPass             bool
-	numTF                 int
-	cancelConnectionTimer func()
-	healthCheckingEnabled bool
-}
-
-// ResolverError is called by the ClientConn when the name resolver produces
-// an error or when pickfirst determined the resolver update to be invalid.
-func (b *pickfirstBalancer) ResolverError(err error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	b.resolverErrorLocked(err)
-}
-
-func (b *pickfirstBalancer) resolverErrorLocked(err error) {
-	if b.logger.V(2) {
-		b.logger.Infof("Received error from the name resolver: %v", err)
-	}
-
-	// The picker will not change since the balancer does not currently
-	// report an error. If the balancer hasn't received a single good resolver
-	// update yet, transition to TRANSIENT_FAILURE.
-	if b.state != connectivity.TransientFailure && b.addressList.size() > 0 {
-		if b.logger.V(2) {
-			b.logger.Infof("Ignoring resolver error because balancer is using a previous good update.")
-		}
-		return
-	}
-
-	b.updateBalancerState(balancer.State{
-		ConnectivityState: connectivity.TransientFailure,
-		Picker:            &picker{err: fmt.Errorf("name resolver error: %v", err)},
-	})
-}
-
-func (b *pickfirstBalancer) UpdateClientConnState(state balancer.ClientConnState) error {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	b.cancelConnectionTimer()
-	if len(state.ResolverState.Addresses) == 0 && len(state.ResolverState.Endpoints) == 0 {
-		// Cleanup state pertaining to the previous resolver state.
-		// Treat an empty address list like an error by calling b.ResolverError.
-		b.closeSubConnsLocked()
-		b.addressList.updateAddrs(nil)
-		b.resolverErrorLocked(errors.New("produced zero addresses"))
-		return balancer.ErrBadResolverState
-	}
-	b.healthCheckingEnabled = state.ResolverState.Attributes.Value(enableHealthListenerKeyType{}) != nil
-	cfg, ok := state.BalancerConfig.(pfConfig)
-	if state.BalancerConfig != nil && !ok {
-		return fmt.Errorf("pickfirst: received illegal BalancerConfig (type %T): %v: %w", state.BalancerConfig, state.BalancerConfig, balancer.ErrBadResolverState)
-	}
-
-	if b.logger.V(2) {
-		b.logger.Infof("Received new config %s, resolver state %s", pretty.ToJSON(cfg), pretty.ToJSON(state.ResolverState))
-	}
-
-	var newAddrs []resolver.Address
-	if endpoints := state.ResolverState.Endpoints; len(endpoints) != 0 {
-		// Perform the optional shuffling described in gRFC A62. The shuffling
-		// will change the order of endpoints but not touch the order of the
-		// addresses within each endpoint. - A61
-		if cfg.ShuffleAddressList {
-			endpoints = append([]resolver.Endpoint{}, endpoints...)
-			internal.RandShuffle(len(endpoints), func(i, j int) { endpoints[i], endpoints[j] = endpoints[j], endpoints[i] })
-		}
-
-		// "Flatten the list by concatenating the ordered list of addresses for
-		// each of the endpoints, in order." - A61
-		for _, endpoint := range endpoints {
-			newAddrs = append(newAddrs, endpoint.Addresses...)
-		}
-	} else {
-		// Endpoints not set, process addresses until we migrate resolver
-		// emissions fully to Endpoints. The top channel does wrap emitted
-		// addresses with endpoints, however some balancers such as weighted
-		// target do not forward the corresponding correct endpoints down/split
-		// endpoints properly. Once all balancers correctly forward endpoints
-		// down, can delete this else conditional.
-		newAddrs = state.ResolverState.Addresses
-		if cfg.ShuffleAddressList {
-			newAddrs = append([]resolver.Address{}, newAddrs...)
-			internal.RandShuffle(len(endpoints), func(i, j int) { endpoints[i], endpoints[j] = endpoints[j], endpoints[i] })
-		}
-	}
-
-	// If an address appears in multiple endpoints or in the same endpoint
-	// multiple times, we keep it only once. We will create only one SubConn
-	// for the address because an AddressMap is used to store SubConns.
-	// Not de-duplicating would result in attempting to connect to the same
-	// SubConn multiple times in the same pass. We don't want this.
-	newAddrs = deDupAddresses(newAddrs)
-	newAddrs = interleaveAddresses(newAddrs)
-
-	prevAddr := b.addressList.currentAddress()
-	prevSCData, found := b.subConns.Get(prevAddr)
-	prevAddrsCount := b.addressList.size()
-	isPrevRawConnectivityStateReady := found && prevSCData.rawConnectivityState == connectivity.Ready
-	b.addressList.updateAddrs(newAddrs)
-
-	// If the previous ready SubConn exists in new address list,
-	// keep this connection and don't create new SubConns.
-	if isPrevRawConnectivityStateReady && b.addressList.seekTo(prevAddr) {
-		return nil
-	}
-
-	b.reconcileSubConnsLocked(newAddrs)
-	// If it's the first resolver update or the balancer was already READY
-	// (but the new address list does not contain the ready SubConn) or
-	// CONNECTING, enter CONNECTING.
-	// We may be in TRANSIENT_FAILURE due to a previous empty address list,
-	// we should still enter CONNECTING because the sticky TF behaviour
-	//  mentioned in A62 applies only when the TRANSIENT_FAILURE is reported
-	// due to connectivity failures.
-	if isPrevRawConnectivityStateReady || b.state == connectivity.Connecting || prevAddrsCount == 0 {
-		// Start connection attempt at first address.
-		b.forceUpdateConcludedStateLocked(balancer.State{
-			ConnectivityState: connectivity.Connecting,
-			Picker:            &picker{err: balancer.ErrNoSubConnAvailable},
-		})
-		b.startFirstPassLocked()
-	} else if b.state == connectivity.TransientFailure {
-		// If we're in TRANSIENT_FAILURE, we stay in TRANSIENT_FAILURE until
-		// we're READY. See A62.
-		b.startFirstPassLocked()
-	}
-	return nil
-}
-
-// UpdateSubConnState is unused as a StateListener is always registered when
-// creating SubConns.
-func (b *pickfirstBalancer) UpdateSubConnState(subConn balancer.SubConn, state balancer.SubConnState) {
-	b.logger.Errorf("UpdateSubConnState(%v, %+v) called unexpectedly", subConn, state)
-}
-
-func (b *pickfirstBalancer) Close() {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	b.closeSubConnsLocked()
-	b.cancelConnectionTimer()
-	b.state = connectivity.Shutdown
-}
-
-// ExitIdle moves the balancer out of idle state. It can be called concurrently
-// by the idlePicker and clientConn so access to variables should be
-// synchronized.
-func (b *pickfirstBalancer) ExitIdle() {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	if b.state == connectivity.Idle {
-		b.startFirstPassLocked()
-	}
-}
-
-func (b *pickfirstBalancer) startFirstPassLocked() {
-	b.firstPass = true
-	b.numTF = 0
-	// Reset the connection attempt record for existing SubConns.
-	for _, sd := range b.subConns.Values() {
-		sd.connectionFailedInFirstPass = false
-	}
-	b.requestConnectionLocked()
-}
-
-func (b *pickfirstBalancer) closeSubConnsLocked() {
-	for _, sd := range b.subConns.Values() {
-		sd.subConn.Shutdown()
-	}
-	b.subConns = resolver.NewAddressMapV2[*scData]()
-}
-
-// deDupAddresses ensures that each address appears only once in the slice.
-func deDupAddresses(addrs []resolver.Address) []resolver.Address {
-	seenAddrs := resolver.NewAddressMapV2[*scData]()
-	retAddrs := []resolver.Address{}
-
-	for _, addr := range addrs {
-		if _, ok := seenAddrs.Get(addr); ok {
-			continue
-		}
-		retAddrs = append(retAddrs, addr)
-	}
-	return retAddrs
-}
-
-// interleaveAddresses interleaves addresses of both families (IPv4 and IPv6)
-// as per RFC-8305 section 4.
-// Whichever address family is first in the list is followed by an address of
-// the other address family; that is, if the first address in the list is IPv6,
-// then the first IPv4 address should be moved up in the list to be second in
-// the list. It doesn't support configuring "First Address Family Count", i.e.
-// there will always be a single member of the first address family at the
-// beginning of the interleaved list.
-// Addresses that are neither IPv4 nor IPv6 are treated as part of a third
-// "unknown" family for interleaving.
-// See: https://datatracker.ietf.org/doc/html/rfc8305#autoid-6
-func interleaveAddresses(addrs []resolver.Address) []resolver.Address {
-	familyAddrsMap := map[ipAddrFamily][]resolver.Address{}
-	interleavingOrder := []ipAddrFamily{}
-	for _, addr := range addrs {
-		family := addressFamily(addr.Addr)
-		if _, found := familyAddrsMap[family]; !found {
-			interleavingOrder = append(interleavingOrder, family)
-		}
-		familyAddrsMap[family] = append(familyAddrsMap[family], addr)
-	}
-
-	interleavedAddrs := make([]resolver.Address, 0, len(addrs))
-
-	for curFamilyIdx := 0; len(interleavedAddrs) < len(addrs); curFamilyIdx = (curFamilyIdx + 1) % len(interleavingOrder) {
-		// Some IP types may have fewer addresses than others, so we look for
-		// the next type that has a remaining member to add to the interleaved
-		// list.
-		family := interleavingOrder[curFamilyIdx]
-		remainingMembers := familyAddrsMap[family]
-		if len(remainingMembers) > 0 {
-			interleavedAddrs = append(interleavedAddrs, remainingMembers[0])
-			familyAddrsMap[family] = remainingMembers[1:]
-		}
-	}
-
-	return interleavedAddrs
-}
-
-// addressFamily returns the ipAddrFamily after parsing the address string.
-// If the address isn't of the format "ip-address:port", it returns
-// ipAddrFamilyUnknown. The address may be valid even if it's not an IP when
-// using a resolver like passthrough where the address may be a hostname in
-// some format that the dialer can resolve.
-func addressFamily(address string) ipAddrFamily {
-	// Parse the IP after removing the port.
-	host, _, err := net.SplitHostPort(address)
-	if err != nil {
-		return ipAddrFamilyUnknown
-	}
-	ip, err := netip.ParseAddr(host)
-	if err != nil {
-		return ipAddrFamilyUnknown
-	}
-	switch {
-	case ip.Is4() || ip.Is4In6():
-		return ipAddrFamilyV4
-	case ip.Is6():
-		return ipAddrFamilyV6
-	default:
-		return ipAddrFamilyUnknown
-	}
-}
-
-// reconcileSubConnsLocked updates the active subchannels based on a new address
-// list from the resolver. It does this by:
-//   - closing subchannels: any existing subchannels associated with addresses
-//     that are no longer in the updated list are shut down.
-//   - removing subchannels: entries for these closed subchannels are removed
-//     from the subchannel map.
-//
-// This ensures that the subchannel map accurately reflects the current set of
-// addresses received from the name resolver.
-func (b *pickfirstBalancer) reconcileSubConnsLocked(newAddrs []resolver.Address) {
-	newAddrsMap := resolver.NewAddressMapV2[bool]()
-	for _, addr := range newAddrs {
-		newAddrsMap.Set(addr, true)
-	}
-
-	for _, oldAddr := range b.subConns.Keys() {
-		if _, ok := newAddrsMap.Get(oldAddr); ok {
-			continue
-		}
-		val, _ := b.subConns.Get(oldAddr)
-		val.subConn.Shutdown()
-		b.subConns.Delete(oldAddr)
-	}
-}
-
-// shutdownRemainingLocked shuts down remaining subConns. Called when a subConn
-// becomes ready, which means that all other subConn must be shutdown.
-func (b *pickfirstBalancer) shutdownRemainingLocked(selected *scData) {
-	b.cancelConnectionTimer()
-	for _, sd := range b.subConns.Values() {
-		if sd.subConn != selected.subConn {
-			sd.subConn.Shutdown()
-		}
-	}
-	b.subConns = resolver.NewAddressMapV2[*scData]()
-	b.subConns.Set(selected.addr, selected)
-}
-
-// requestConnectionLocked starts connecting on the subchannel corresponding to
-// the current address. If no subchannel exists, one is created. If the current
-// subchannel is in TransientFailure, a connection to the next address is
-// attempted until a subchannel is found.
-func (b *pickfirstBalancer) requestConnectionLocked() {
-	if !b.addressList.isValid() {
-		return
-	}
-	var lastErr error
-	for valid := true; valid; valid = b.addressList.increment() {
-		curAddr := b.addressList.currentAddress()
-		sd, ok := b.subConns.Get(curAddr)
-		if !ok {
-			var err error
-			// We want to assign the new scData to sd from the outer scope,
-			// hence we can't use := below.
-			sd, err = b.newSCData(curAddr)
-			if err != nil {
-				// This should never happen, unless the clientConn is being shut
-				// down.
-				if b.logger.V(2) {
-					b.logger.Infof("Failed to create a subConn for address %v: %v", curAddr.String(), err)
-				}
-				// Do nothing, the LB policy will be closed soon.
-				return
-			}
-			b.subConns.Set(curAddr, sd)
-		}
-
-		switch sd.rawConnectivityState {
-		case connectivity.Idle:
-			sd.subConn.Connect()
-			b.scheduleNextConnectionLocked()
-			return
-		case connectivity.TransientFailure:
-			// The SubConn is being re-used and failed during a previous pass
-			// over the addressList. It has not completed backoff yet.
-			// Mark it as having failed and try the next address.
-			sd.connectionFailedInFirstPass = true
-			lastErr = sd.lastErr
-			continue
-		case connectivity.Connecting:
-			// Wait for the connection attempt to complete or the timer to fire
-			// before attempting the next address.
-			b.scheduleNextConnectionLocked()
-			return
-		default:
-			b.logger.Errorf("SubConn with unexpected state %v present in SubConns map.", sd.rawConnectivityState)
-			return
-
-		}
-	}
-
-	// All the remaining addresses in the list are in TRANSIENT_FAILURE, end the
-	// first pass if possible.
-	b.endFirstPassIfPossibleLocked(lastErr)
-}
-
-func (b *pickfirstBalancer) scheduleNextConnectionLocked() {
-	b.cancelConnectionTimer()
-	if !b.addressList.hasNext() {
-		return
-	}
-	curAddr := b.addressList.currentAddress()
-	cancelled := false // Access to this is protected by the balancer's mutex.
-	closeFn := internal.TimeAfterFunc(connectionDelayInterval, func() {
-		b.mu.Lock()
-		defer b.mu.Unlock()
-		// If the scheduled task is cancelled while acquiring the mutex, return.
-		if cancelled {
-			return
-		}
-		if b.logger.V(2) {
-			b.logger.Infof("Happy Eyeballs timer expired while waiting for connection to %q.", curAddr.Addr)
-		}
-		if b.addressList.increment() {
-			b.requestConnectionLocked()
-		}
-	})
-	// Access to the cancellation callback held by the balancer is guarded by
-	// the balancer's mutex, so it's safe to set the boolean from the callback.
-	b.cancelConnectionTimer = sync.OnceFunc(func() {
-		cancelled = true
-		closeFn()
-	})
-}
-
-func (b *pickfirstBalancer) updateSubConnState(sd *scData, newState balancer.SubConnState) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	oldState := sd.rawConnectivityState
-	sd.rawConnectivityState = newState.ConnectivityState
-	// Previously relevant SubConns can still callback with state updates.
-	// To prevent pickers from returning these obsolete SubConns, this logic
-	// is included to check if the current list of active SubConns includes this
-	// SubConn.
-	if !b.isActiveSCData(sd) {
-		return
-	}
-	if newState.ConnectivityState == connectivity.Shutdown {
-		sd.effectiveState = connectivity.Shutdown
-		return
-	}
-
-	// Record a connection attempt when exiting CONNECTING.
-	if newState.ConnectivityState == connectivity.TransientFailure {
-		sd.connectionFailedInFirstPass = true
-		connectionAttemptsFailedMetric.Record(b.metricsRecorder, 1, b.target)
-	}
-
-	if newState.ConnectivityState == connectivity.Ready {
-		connectionAttemptsSucceededMetric.Record(b.metricsRecorder, 1, b.target)
-		b.shutdownRemainingLocked(sd)
-		if !b.addressList.seekTo(sd.addr) {
-			// This should not fail as we should have only one SubConn after
-			// entering READY. The SubConn should be present in the addressList.
-			b.logger.Errorf("Address %q not found address list in  %v", sd.addr, b.addressList.addresses)
-			return
-		}
-		if !b.healthCheckingEnabled {
-			if b.logger.V(2) {
-				b.logger.Infof("SubConn %p reported connectivity state READY and the health listener is disabled. Transitioning SubConn to READY.", sd.subConn)
-			}
-
-			sd.effectiveState = connectivity.Ready
-			b.updateBalancerState(balancer.State{
-				ConnectivityState: connectivity.Ready,
-				Picker:            &picker{result: balancer.PickResult{SubConn: sd.subConn}},
-			})
-			return
-		}
-		if b.logger.V(2) {
-			b.logger.Infof("SubConn %p reported connectivity state READY. Registering health listener.", sd.subConn)
-		}
-		// Send a CONNECTING update to take the SubConn out of sticky-TF if
-		// required.
-		sd.effectiveState = connectivity.Connecting
-		b.updateBalancerState(balancer.State{
-			ConnectivityState: connectivity.Connecting,
-			Picker:            &picker{err: balancer.ErrNoSubConnAvailable},
-		})
-		sd.subConn.RegisterHealthListener(func(scs balancer.SubConnState) {
-			b.updateSubConnHealthState(sd, scs)
-		})
-		return
-	}
-
-	// If the LB policy is READY, and it receives a subchannel state change,
-	// it means that the READY subchannel has failed.
-	// A SubConn can also transition from CONNECTING directly to IDLE when
-	// a transport is successfully created, but the connection fails
-	// before the SubConn can send the notification for READY. We treat
-	// this as a successful connection and transition to IDLE.
-	// TODO: https://github.com/grpc/grpc-go/issues/7862 - Remove the second
-	// part of the if condition below once the issue is fixed.
-	if oldState == connectivity.Ready || (oldState == connectivity.Connecting && newState.ConnectivityState == connectivity.Idle) {
-		// Once a transport fails, the balancer enters IDLE and starts from
-		// the first address when the picker is used.
-		b.shutdownRemainingLocked(sd)
-		sd.effectiveState = newState.ConnectivityState
-		// READY SubConn interspliced in between CONNECTING and IDLE, need to
-		// account for that.
-		if oldState == connectivity.Connecting {
-			// A known issue (https://github.com/grpc/grpc-go/issues/7862)
-			// causes a race that prevents the READY state change notification.
-			// This works around it.
-			connectionAttemptsSucceededMetric.Record(b.metricsRecorder, 1, b.target)
-		}
-		disconnectionsMetric.Record(b.metricsRecorder, 1, b.target)
-		b.addressList.reset()
-		b.updateBalancerState(balancer.State{
-			ConnectivityState: connectivity.Idle,
-			Picker:            &idlePicker{exitIdle: sync.OnceFunc(b.ExitIdle)},
-		})
-		return
-	}
-
-	if b.firstPass {
-		switch newState.ConnectivityState {
-		case connectivity.Connecting:
-			// The effective state can be in either IDLE, CONNECTING or
-			// TRANSIENT_FAILURE. If it's  TRANSIENT_FAILURE, stay in
-			// TRANSIENT_FAILURE until it's READY. See A62.
-			if sd.effectiveState != connectivity.TransientFailure {
-				sd.effectiveState = connectivity.Connecting
-				b.updateBalancerState(balancer.State{
-					ConnectivityState: connectivity.Connecting,
-					Picker:            &picker{err: balancer.ErrNoSubConnAvailable},
-				})
-			}
-		case connectivity.TransientFailure:
-			sd.lastErr = newState.ConnectionError
-			sd.effectiveState = connectivity.TransientFailure
-			// Since we're re-using common SubConns while handling resolver
-			// updates, we could receive an out of turn TRANSIENT_FAILURE from
-			// a pass over the previous address list. Happy Eyeballs will also
-			// cause out of order updates to arrive.
-
-			if curAddr := b.addressList.currentAddress(); equalAddressIgnoringBalAttributes(&curAddr, &sd.addr) {
-				b.cancelConnectionTimer()
-				if b.addressList.increment() {
-					b.requestConnectionLocked()
-					return
-				}
-			}
-
-			// End the first pass if we've seen a TRANSIENT_FAILURE from all
-			// SubConns once.
-			b.endFirstPassIfPossibleLocked(newState.ConnectionError)
-		}
-		return
-	}
-
-	// We have finished the first pass, keep re-connecting failing SubConns.
-	switch newState.ConnectivityState {
-	case connectivity.TransientFailure:
-		b.numTF = (b.numTF + 1) % b.subConns.Len()
-		sd.lastErr = newState.ConnectionError
-		if b.numTF%b.subConns.Len() == 0 {
-			b.updateBalancerState(balancer.State{
-				ConnectivityState: connectivity.TransientFailure,
-				Picker:            &picker{err: newState.ConnectionError},
-			})
-		}
-		// We don't need to request re-resolution since the SubConn already
-		// does that before reporting TRANSIENT_FAILURE.
-		// TODO: #7534 - Move re-resolution requests from SubConn into
-		// pick_first.
-	case connectivity.Idle:
-		sd.subConn.Connect()
-	}
-}
-
-// endFirstPassIfPossibleLocked ends the first happy-eyeballs pass if all the
-// addresses are tried and their SubConns have reported a failure.
-func (b *pickfirstBalancer) endFirstPassIfPossibleLocked(lastErr error) {
-	// An optimization to avoid iterating over the entire SubConn map.
-	if b.addressList.isValid() {
-		return
-	}
-	// Connect() has been called on all the SubConns. The first pass can be
-	// ended if all the SubConns have reported a failure.
-	for _, sd := range b.subConns.Values() {
-		if !sd.connectionFailedInFirstPass {
-			return
-		}
-	}
-	b.firstPass = false
-	b.updateBalancerState(balancer.State{
-		ConnectivityState: connectivity.TransientFailure,
-		Picker:            &picker{err: lastErr},
-	})
-	// Start re-connecting all the SubConns that are already in IDLE.
-	for _, sd := range b.subConns.Values() {
-		if sd.rawConnectivityState == connectivity.Idle {
-			sd.subConn.Connect()
-		}
-	}
-}
-
-func (b *pickfirstBalancer) isActiveSCData(sd *scData) bool {
-	activeSD, found := b.subConns.Get(sd.addr)
-	return found && activeSD == sd
-}
-
-func (b *pickfirstBalancer) updateSubConnHealthState(sd *scData, state balancer.SubConnState) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	// Previously relevant SubConns can still callback with state updates.
-	// To prevent pickers from returning these obsolete SubConns, this logic
-	// is included to check if the current list of active SubConns includes
-	// this SubConn.
-	if !b.isActiveSCData(sd) {
-		return
-	}
-	sd.effectiveState = state.ConnectivityState
-	switch state.ConnectivityState {
-	case connectivity.Ready:
-		b.updateBalancerState(balancer.State{
-			ConnectivityState: connectivity.Ready,
-			Picker:            &picker{result: balancer.PickResult{SubConn: sd.subConn}},
-		})
-	case connectivity.TransientFailure:
-		b.updateBalancerState(balancer.State{
-			ConnectivityState: connectivity.TransientFailure,
-			Picker:            &picker{err: fmt.Errorf("pickfirst: health check failure: %v", state.ConnectionError)},
-		})
-	case connectivity.Connecting:
-		b.updateBalancerState(balancer.State{
-			ConnectivityState: connectivity.Connecting,
-			Picker:            &picker{err: balancer.ErrNoSubConnAvailable},
-		})
-	default:
-		b.logger.Errorf("Got unexpected health update for SubConn %p: %v", state)
-	}
-}
-
-// updateBalancerState stores the state reported to the channel and calls
-// ClientConn.UpdateState(). As an optimization, it avoids sending duplicate
-// updates to the channel.
-func (b *pickfirstBalancer) updateBalancerState(newState balancer.State) {
-	// In case of TransientFailures allow the picker to be updated to update
-	// the connectivity error, in all other cases don't send duplicate state
-	// updates.
-	if newState.ConnectivityState == b.state && b.state != connectivity.TransientFailure {
-		return
-	}
-	b.forceUpdateConcludedStateLocked(newState)
-}
-
-// forceUpdateConcludedStateLocked stores the state reported to the channel and
-// calls ClientConn.UpdateState().
-// A separate function is defined to force update the ClientConn state since the
-// channel doesn't correctly assume that LB policies start in CONNECTING and
-// relies on LB policy to send an initial CONNECTING update.
-func (b *pickfirstBalancer) forceUpdateConcludedStateLocked(newState balancer.State) {
-	b.state = newState.ConnectivityState
-	b.cc.UpdateState(newState)
-}
-
-type picker struct {
-	result balancer.PickResult
-	err    error
-}
-
-func (p *picker) Pick(balancer.PickInfo) (balancer.PickResult, error) {
-	return p.result, p.err
-}
-
-// idlePicker is used when the SubConn is IDLE and kicks the SubConn into
-// CONNECTING when Pick is called.
-type idlePicker struct {
-	exitIdle func()
-}
-
-func (i *idlePicker) Pick(balancer.PickInfo) (balancer.PickResult, error) {
-	i.exitIdle()
-	return balancer.PickResult{}, balancer.ErrNoSubConnAvailable
-}
-
-// addressList manages sequentially iterating over addresses present in a list
-// of endpoints. It provides a 1 dimensional view of the addresses present in
-// the endpoints.
-// This type is not safe for concurrent access.
-type addressList struct {
-	addresses []resolver.Address
-	idx       int
-}
-
-func (al *addressList) isValid() bool {
-	return al.idx < len(al.addresses)
-}
-
-func (al *addressList) size() int {
-	return len(al.addresses)
-}
-
-// increment moves to the next index in the address list.
-// This method returns false if it went off the list, true otherwise.
-func (al *addressList) increment() bool {
-	if !al.isValid() {
-		return false
-	}
-	al.idx++
-	return al.idx < len(al.addresses)
-}
-
-// currentAddress returns the current address pointed to in the addressList.
-// If the list is in an invalid state, it returns an empty address instead.
-func (al *addressList) currentAddress() resolver.Address {
-	if !al.isValid() {
-		return resolver.Address{}
-	}
-	return al.addresses[al.idx]
-}
-
-func (al *addressList) reset() {
-	al.idx = 0
-}
-
-func (al *addressList) updateAddrs(addrs []resolver.Address) {
-	al.addresses = addrs
-	al.reset()
-}
-
-// seekTo returns false if the needle was not found and the current index was
-// left unchanged.
-func (al *addressList) seekTo(needle resolver.Address) bool {
-	for ai, addr := range al.addresses {
-		if !equalAddressIgnoringBalAttributes(&addr, &needle) {
-			continue
-		}
-		al.idx = ai
-		return true
-	}
-	return false
-}
-
-// hasNext returns whether incrementing the addressList will result in moving
-// past the end of the list. If the list has already moved past the end, it
-// returns false.
-func (al *addressList) hasNext() bool {
-	if !al.isValid() {
-		return false
-	}
-	return al.idx+1 < len(al.addresses)
-}
-
-// equalAddressIgnoringBalAttributes returns true is a and b are considered
-// equal. This is different from the Equal method on the resolver.Address type
-// which considers all fields to determine equality. Here, we only consider
-// fields that are meaningful to the SubConn.
-func equalAddressIgnoringBalAttributes(a, b *resolver.Address) bool {
-	return a.Addr == b.Addr && a.ServerName == b.ServerName &&
-		a.Attributes.Equal(b.Attributes)
-}
@@ -26,7 +26,7 @@ import (

 	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/balancer/endpointsharding"
-	"google.golang.org/grpc/balancer/pickfirst/pickfirstleaf"
+	"google.golang.org/grpc/balancer/pickfirst"
 	"google.golang.org/grpc/grpclog"
 	internalgrpclog "google.golang.org/grpc/internal/grpclog"
 )
@@ -47,7 +47,7 @@ func (bb builder) Name() string {
 }

 func (bb builder) Build(cc balancer.ClientConn, opts balancer.BuildOptions) balancer.Balancer {
-	childBuilder := balancer.Get(pickfirstleaf.Name).Build
+	childBuilder := balancer.Get(pickfirst.Name).Build
 	bal := &rrBalancer{
 		cc:       cc,
 		Balancer: endpointsharding.NewBalancer(cc, opts, childBuilder, endpointsharding.Options{}),
@@ -67,6 +67,6 @@ func (b *rrBalancer) UpdateClientConnState(ccs balancer.ClientConnState) error {
 	return b.Balancer.UpdateClientConnState(balancer.ClientConnState{
 		// Enable the health listener in pickfirst children for client side health
 		// checks and outlier detection, if configured.
-		ResolverState: pickfirstleaf.EnableHealthListener(ccs.ResolverState),
+		ResolverState: pickfirst.EnableHealthListener(ccs.ResolverState),
 	})
 }
@@ -111,20 +111,6 @@ type SubConnState struct {
 	// ConnectionError is set if the ConnectivityState is TransientFailure,
 	// describing the reason the SubConn failed.  Otherwise, it is nil.
 	ConnectionError error
-	// connectedAddr contains the connected address when ConnectivityState is
-	// Ready. Otherwise, it is indeterminate.
-	connectedAddress resolver.Address
-}
-
-// connectedAddress returns the connected address for a SubConnState. The
-// address is only valid if the state is READY.
-func connectedAddress(scs SubConnState) resolver.Address {
-	return scs.connectedAddress
-}
-
-// setConnectedAddress sets the connected address for a SubConnState.
-func setConnectedAddress(scs *SubConnState, addr resolver.Address) {
-	scs.connectedAddress = addr
 }

 // A Producer is a type shared among potentially many consumers.  It is
@@ -36,7 +36,6 @@ import (
 )

 var (
-	setConnectedAddress = internal.SetConnectedAddress.(func(*balancer.SubConnState, resolver.Address))
 	// noOpRegisterHealthListenerFn is used when client side health checking is
 	// disabled. It sends a single READY update on the registered listener.
 	noOpRegisterHealthListenerFn = func(_ context.Context, listener func(balancer.SubConnState)) func() {
@@ -305,7 +304,7 @@ func newHealthData(s connectivity.State) *healthData {

 // updateState is invoked by grpc to push a subConn state update to the
 // underlying balancer.
-func (acbw *acBalancerWrapper) updateState(s connectivity.State, curAddr resolver.Address, err error) {
+func (acbw *acBalancerWrapper) updateState(s connectivity.State, err error) {
 	acbw.ccb.serializer.TrySchedule(func(ctx context.Context) {
 		if ctx.Err() != nil || acbw.ccb.balancer == nil {
 			return
@@ -317,9 +316,6 @@ func (acbw *acBalancerWrapper) updateState(s connectivity.State, curAddr resolve
 		// opts.StateListener is set, so this cannot ever be nil.
 		// TODO: delete this comment when UpdateSubConnState is removed.
 		scs := balancer.SubConnState{ConnectivityState: s, ConnectionError: err}
-		if s == connectivity.Ready {
-			setConnectedAddress(&scs, curAddr)
-		}
 		// Invalidate the health listener by updating the healthData.
 		acbw.healthMu.Lock()
 		// A race may occur if a health listener is registered soon after the
@@ -450,13 +446,14 @@ func (acbw *acBalancerWrapper) healthListenerRegFn() func(context.Context, func(
 	if acbw.ccb.cc.dopts.disableHealthCheck {
 		return noOpRegisterHealthListenerFn
 	}
+	cfg := acbw.ac.cc.healthCheckConfig()
+	if cfg == nil {
+		return noOpRegisterHealthListenerFn
+	}
 	regHealthLisFn := internal.RegisterClientHealthCheckListener
 	if regHealthLisFn == nil {
 		// The health package is not imported.
-		return noOpRegisterHealthListenerFn
-	}
-	cfg := acbw.ac.cc.healthCheckConfig()
-	if cfg == nil {
+		channelz.Error(logger, acbw.ac.channelz, "Health check is requested but health package is not imported.")
 		return noOpRegisterHealthListenerFn
 	}
 	return func(ctx context.Context, listener func(balancer.SubConnState)) func() {
@@ -18,7 +18,7 @@

 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
-// 	protoc-gen-go v1.36.6
+// 	protoc-gen-go v1.36.10
 // 	protoc        v5.27.1
 // source: grpc/binlog/v1/binarylog.proto

@@ -35,16 +35,19 @@ import (
 	"google.golang.org/grpc/balancer/pickfirst"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/credentials"
+	expstats "google.golang.org/grpc/experimental/stats"
 	"google.golang.org/grpc/internal"
 	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/internal/grpcsync"
 	"google.golang.org/grpc/internal/idle"
 	iresolver "google.golang.org/grpc/internal/resolver"
-	"google.golang.org/grpc/internal/stats"
+	istats "google.golang.org/grpc/internal/stats"
 	"google.golang.org/grpc/internal/transport"
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/resolver"
 	"google.golang.org/grpc/serviceconfig"
+	"google.golang.org/grpc/stats"
 	"google.golang.org/grpc/status"

 	_ "google.golang.org/grpc/balancer/roundrobin"           // To register roundrobin.
@@ -97,6 +100,41 @@ var (
 	errTransportCredentialsMissing = errors.New("grpc: the credentials require transport level security (use grpc.WithTransportCredentials() to set)")
 )

+var (
+	disconnectionsMetric = expstats.RegisterInt64Count(expstats.MetricDescriptor{
+		Name:           "grpc.subchannel.disconnections",
+		Description:    "EXPERIMENTAL. Number of times the selected subchannel becomes disconnected.",
+		Unit:           "{disconnection}",
+		Labels:         []string{"grpc.target"},
+		OptionalLabels: []string{"grpc.lb.backend_service", "grpc.lb.locality", "grpc.disconnect_error"},
+		Default:        false,
+	})
+	connectionAttemptsSucceededMetric = expstats.RegisterInt64Count(expstats.MetricDescriptor{
+		Name:           "grpc.subchannel.connection_attempts_succeeded",
+		Description:    "EXPERIMENTAL. Number of successful connection attempts.",
+		Unit:           "{attempt}",
+		Labels:         []string{"grpc.target"},
+		OptionalLabels: []string{"grpc.lb.backend_service", "grpc.lb.locality"},
+		Default:        false,
+	})
+	connectionAttemptsFailedMetric = expstats.RegisterInt64Count(expstats.MetricDescriptor{
+		Name:           "grpc.subchannel.connection_attempts_failed",
+		Description:    "EXPERIMENTAL. Number of failed connection attempts.",
+		Unit:           "{attempt}",
+		Labels:         []string{"grpc.target"},
+		OptionalLabels: []string{"grpc.lb.backend_service", "grpc.lb.locality"},
+		Default:        false,
+	})
+	openConnectionsMetric = expstats.RegisterInt64UpDownCount(expstats.MetricDescriptor{
+		Name:           "grpc.subchannel.open_connections",
+		Description:    "EXPERIMENTAL. Number of open connections.",
+		Unit:           "{attempt}",
+		Labels:         []string{"grpc.target"},
+		OptionalLabels: []string{"grpc.lb.backend_service", "grpc.security_level", "grpc.lb.locality"},
+		Default:        false,
+	})
+)
+
 const (
 	defaultClientMaxReceiveMessageSize = 1024 * 1024 * 4
 	defaultClientMaxSendMessageSize    = math.MaxInt32
@@ -208,9 +246,10 @@ func NewClient(target string, opts ...DialOption) (conn *ClientConn, err error)
 	channelz.Infof(logger, cc.channelz, "Channel authority set to %q", cc.authority)

 	cc.csMgr = newConnectivityStateManager(cc.ctx, cc.channelz)
-	cc.pickerWrapper = newPickerWrapper(cc.dopts.copts.StatsHandlers)
+	cc.pickerWrapper = newPickerWrapper()

-	cc.metricsRecorderList = stats.NewMetricsRecorderList(cc.dopts.copts.StatsHandlers)
+	cc.metricsRecorderList = istats.NewMetricsRecorderList(cc.dopts.copts.StatsHandlers)
+	cc.statsHandler = istats.NewCombinedHandler(cc.dopts.copts.StatsHandlers...)

 	cc.initIdleStateLocked() // Safe to call without the lock, since nothing else has a reference to cc.
 	cc.idlenessMgr = idle.NewManager((*idler)(cc), cc.dopts.idleTimeout)
@@ -260,9 +299,10 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 	}()

 	// This creates the name resolver, load balancer, etc.
-	if err := cc.idlenessMgr.ExitIdleMode(); err != nil {
-		return nil, err
+	if err := cc.exitIdleMode(); err != nil {
+		return nil, fmt.Errorf("failed to exit idle mode: %w", err)
 	}
+	cc.idlenessMgr.UnsafeSetNotIdle()

 	// Return now for non-blocking dials.
 	if !cc.dopts.block {
@@ -330,7 +370,7 @@ func (cc *ClientConn) addTraceEvent(msg string) {
 			Severity: channelz.CtInfo,
 		}
 	}
-	channelz.AddTraceEvent(logger, cc.channelz, 0, ted)
+	channelz.AddTraceEvent(logger, cc.channelz, 1, ted)
 }

 type idler ClientConn
@@ -339,14 +379,17 @@ func (i *idler) EnterIdleMode() {
 	(*ClientConn)(i).enterIdleMode()
 }

-func (i *idler) ExitIdleMode() error {
-	return (*ClientConn)(i).exitIdleMode()
+func (i *idler) ExitIdleMode() {
+	// Ignore the error returned from this method, because from the perspective
+	// of the caller (idleness manager), the channel would have always moved out
+	// of IDLE by the time this method returns.
+	(*ClientConn)(i).exitIdleMode()
 }

 // exitIdleMode moves the channel out of idle mode by recreating the name
 // resolver and load balancer.  This should never be called directly; use
 // cc.idlenessMgr.ExitIdleMode instead.
-func (cc *ClientConn) exitIdleMode() (err error) {
+func (cc *ClientConn) exitIdleMode() error {
 	cc.mu.Lock()
 	if cc.conns == nil {
 		cc.mu.Unlock()
@@ -354,11 +397,23 @@ func (cc *ClientConn) exitIdleMode() (err error) {
 	}
 	cc.mu.Unlock()

+	// Set state to CONNECTING before building the name resolver
+	// so the channel does not remain in IDLE.
+	cc.csMgr.updateState(connectivity.Connecting)
+
 	// This needs to be called without cc.mu because this builds a new resolver
 	// which might update state or report error inline, which would then need to
 	// acquire cc.mu.
 	if err := cc.resolverWrapper.start(); err != nil {
-		return err
+		// If resolver creation fails, treat it like an error reported by the
+		// resolver before any valid updates. Set channel's state to
+		// TransientFailure, and set an erroring picker with the resolver build
+		// error, which will returned as part of any subsequent RPCs.
+		logger.Warningf("Failed to start resolver: %v", err)
+		cc.csMgr.updateState(connectivity.TransientFailure)
+		cc.mu.Lock()
+		cc.updateResolverStateAndUnlock(resolver.State{}, err)
+		return fmt.Errorf("failed to start resolver: %w", err)
 	}

 	cc.addTraceEvent("exiting idle mode")
@@ -456,7 +511,7 @@ func (cc *ClientConn) validateTransportCredentials() error {
 func (cc *ClientConn) channelzRegistration(target string) {
 	parentChannel, _ := cc.dopts.channelzParent.(*channelz.Channel)
 	cc.channelz = channelz.RegisterChannel(parentChannel, target)
-	cc.addTraceEvent("created")
+	cc.addTraceEvent(fmt.Sprintf("created for target %q", target))
 }

 // chainUnaryClientInterceptors chains all unary client interceptors into one.
@@ -621,7 +676,8 @@ type ClientConn struct {
 	channelz            *channelz.Channel // Channelz object.
 	resolverBuilder     resolver.Builder  // See initParsedTargetAndResolverBuilder().
 	idlenessMgr         *idle.Manager
-	metricsRecorderList *stats.MetricsRecorderList
+	metricsRecorderList *istats.MetricsRecorderList
+	statsHandler        stats.Handler

 	// The following provide their own synchronization, and therefore don't
 	// require cc.mu to be held to access them.
@@ -678,10 +734,8 @@ func (cc *ClientConn) GetState() connectivity.State {
 // Notice: This API is EXPERIMENTAL and may be changed or removed in a later
 // release.
 func (cc *ClientConn) Connect() {
-	if err := cc.idlenessMgr.ExitIdleMode(); err != nil {
-		cc.addTraceEvent(err.Error())
-		return
-	}
+	cc.idlenessMgr.ExitIdleMode()
+
 	// If the ClientConn was not in idle mode, we need to call ExitIdle on the
 	// LB policy so that connections can be created.
 	cc.mu.Lock()
@@ -732,8 +786,8 @@ func init() {
 	internal.EnterIdleModeForTesting = func(cc *ClientConn) {
 		cc.idlenessMgr.EnterIdleModeForTesting()
 	}
-	internal.ExitIdleModeForTesting = func(cc *ClientConn) error {
-		return cc.idlenessMgr.ExitIdleMode()
+	internal.ExitIdleModeForTesting = func(cc *ClientConn) {
+		cc.idlenessMgr.ExitIdleMode()
 	}
 }

@@ -858,6 +912,7 @@ func (cc *ClientConn) newAddrConnLocked(addrs []resolver.Address, opts balancer.
 		channelz:     channelz.RegisterSubChannel(cc.channelz, ""),
 		resetBackoff: make(chan struct{}),
 	}
+	ac.updateTelemetryLabelsLocked()
 	ac.ctx, ac.cancel = context.WithCancel(cc.ctx)
 	// Start with our address set to the first address; this may be updated if
 	// we connect to different addresses.
@@ -922,25 +977,24 @@ func (cc *ClientConn) incrCallsFailed() {
 // connect starts creating a transport.
 // It does nothing if the ac is not IDLE.
 // TODO(bar) Move this to the addrConn section.
-func (ac *addrConn) connect() error {
+func (ac *addrConn) connect() {
 	ac.mu.Lock()
 	if ac.state == connectivity.Shutdown {
 		if logger.V(2) {
 			logger.Infof("connect called on shutdown addrConn; ignoring.")
 		}
 		ac.mu.Unlock()
-		return errConnClosing
+		return
 	}
 	if ac.state != connectivity.Idle {
 		if logger.V(2) {
 			logger.Infof("connect called on addrConn in non-idle state (%v); ignoring.", ac.state)
 		}
 		ac.mu.Unlock()
-		return nil
+		return
 	}

 	ac.resetTransportAndUnlock()
-	return nil
 }

 // equalAddressIgnoringBalAttributes returns true is a and b are considered equal.
@@ -974,7 +1028,7 @@ func (ac *addrConn) updateAddrs(addrs []resolver.Address) {
 	}

 	ac.addrs = addrs
-
+	ac.updateTelemetryLabelsLocked()
 	if ac.state == connectivity.Shutdown ||
 		ac.state == connectivity.TransientFailure ||
 		ac.state == connectivity.Idle {
@@ -1076,13 +1130,6 @@ func (cc *ClientConn) healthCheckConfig() *healthCheckConfig {
 	return cc.sc.healthCheckConfig
 }

-func (cc *ClientConn) getTransport(ctx context.Context, failfast bool, method string) (transport.ClientTransport, balancer.PickResult, error) {
-	return cc.pickerWrapper.pick(ctx, failfast, balancer.PickInfo{
-		Ctx:            ctx,
-		FullMethodName: method,
-	})
-}
-
 func (cc *ClientConn) applyServiceConfigAndBalancer(sc *ServiceConfig, configSelector iresolver.ConfigSelector) {
 	if sc == nil {
 		// should never reach here.
@@ -1220,6 +1267,9 @@ type addrConn struct {
 	resetBackoff chan struct{}

 	channelz *channelz.SubChannel
+
+	localityLabel       string
+	backendServiceLabel string
 }

 // Note: this requires a lock on ac.mu.
@@ -1227,6 +1277,18 @@ func (ac *addrConn) updateConnectivityState(s connectivity.State, lastErr error)
 	if ac.state == s {
 		return
 	}
+
+	// If we are transitioning out of Ready, it means there is a disconnection.
+	// A SubConn can also transition from CONNECTING directly to IDLE when
+	// a transport is successfully created, but the connection fails
+	// before the SubConn can send the notification for READY. We treat
+	// this as a successful connection and transition to IDLE.
+	// TODO: https://github.com/grpc/grpc-go/issues/7862 - Remove the second
+	// part of the if condition below once the issue is fixed.
+	if ac.state == connectivity.Ready || (ac.state == connectivity.Connecting && s == connectivity.Idle) {
+		disconnectionsMetric.Record(ac.cc.metricsRecorderList, 1, ac.cc.target, ac.backendServiceLabel, ac.localityLabel, "unknown")
+		openConnectionsMetric.Record(ac.cc.metricsRecorderList, -1, ac.cc.target, ac.backendServiceLabel, ac.securityLevelLocked(), ac.localityLabel)
+	}
 	ac.state = s
 	ac.channelz.ChannelMetrics.State.Store(&s)
 	if lastErr == nil {
@@ -1234,7 +1296,7 @@ func (ac *addrConn) updateConnectivityState(s connectivity.State, lastErr error)
 	} else {
 		channelz.Infof(logger, ac.channelz, "Subchannel Connectivity change to %v, last error: %s", s, lastErr)
 	}
-	ac.acbw.updateState(s, ac.curAddr, lastErr)
+	ac.acbw.updateState(s, lastErr)
 }

 // adjustParams updates parameters used to create transports upon
@@ -1284,6 +1346,15 @@ func (ac *addrConn) resetTransportAndUnlock() {
 	ac.mu.Unlock()

 	if err := ac.tryAllAddrs(acCtx, addrs, connectDeadline); err != nil {
+		if !errors.Is(err, context.Canceled) {
+			connectionAttemptsFailedMetric.Record(ac.cc.metricsRecorderList, 1, ac.cc.target, ac.backendServiceLabel, ac.localityLabel)
+		} else {
+			if logger.V(2) {
+				// This records cancelled connection attempts which can be later
+				// replaced by a metric.
+				logger.Infof("Context cancellation detected; not recording this as a failed connection attempt.")
+			}
+		}
 		// TODO: #7534 - Move re-resolution requests into the pick_first LB policy
 		// to ensure one resolution request per pass instead of per subconn failure.
 		ac.cc.resolveNow(resolver.ResolveNowOptions{})
@@ -1323,10 +1394,50 @@ func (ac *addrConn) resetTransportAndUnlock() {
 	}
 	// Success; reset backoff.
 	ac.mu.Lock()
+	connectionAttemptsSucceededMetric.Record(ac.cc.metricsRecorderList, 1, ac.cc.target, ac.backendServiceLabel, ac.localityLabel)
+	openConnectionsMetric.Record(ac.cc.metricsRecorderList, 1, ac.cc.target, ac.backendServiceLabel, ac.securityLevelLocked(), ac.localityLabel)
 	ac.backoffIdx = 0
 	ac.mu.Unlock()
 }

+// updateTelemetryLabelsLocked calculates and caches the telemetry labels based on the
+// first address in addrConn.
+func (ac *addrConn) updateTelemetryLabelsLocked() {
+	labelsFunc, ok := internal.AddressToTelemetryLabels.(func(resolver.Address) map[string]string)
+	if !ok || len(ac.addrs) == 0 {
+		// Reset defaults
+		ac.localityLabel = ""
+		ac.backendServiceLabel = ""
+		return
+	}
+	labels := labelsFunc(ac.addrs[0])
+	ac.localityLabel = labels["grpc.lb.locality"]
+	ac.backendServiceLabel = labels["grpc.lb.backend_service"]
+}
+
+type securityLevelKey struct{}
+
+func (ac *addrConn) securityLevelLocked() string {
+	var secLevel string
+	// During disconnection, ac.transport is nil. Fall back to the security level
+	// stored in the current address during connection.
+	if ac.transport == nil {
+		secLevel, _ = ac.curAddr.Attributes.Value(securityLevelKey{}).(string)
+		return secLevel
+	}
+	authInfo := ac.transport.Peer().AuthInfo
+	if ci, ok := authInfo.(interface {
+		GetCommonAuthInfo() credentials.CommonAuthInfo
+	}); ok {
+		secLevel = ci.GetCommonAuthInfo().SecurityLevel.String()
+		// Store the security level in the current address' attributes so
+		// that it remains available for disconnection metrics after the
+		// transport is closed.
+		ac.curAddr.Attributes = ac.curAddr.Attributes.WithValue(securityLevelKey{}, secLevel)
+	}
+	return secLevel
+}
+
 // tryAllAddrs tries to create a connection to the addresses, and stop when at
 // the first successful one. It returns an error if no address was successfully
 // connected, or updates ac appropriately with the new transport.
@@ -1416,25 +1527,26 @@ func (ac *addrConn) createTransport(ctx context.Context, addr resolver.Address,
 	}

 	ac.mu.Lock()
-	defer ac.mu.Unlock()
 	if ctx.Err() != nil {
 		// This can happen if the subConn was removed while in `Connecting`
 		// state. tearDown() would have set the state to `Shutdown`, but
 		// would not have closed the transport since ac.transport would not
 		// have been set at that point.
-		//
-		// We run this in a goroutine because newTr.Close() calls onClose()
+
+		// We unlock ac.mu because newTr.Close() calls onClose()
 		// inline, which requires locking ac.mu.
-		//
+		ac.mu.Unlock()
+
 		// The error we pass to Close() is immaterial since there are no open
 		// streams at this point, so no trailers with error details will be sent
 		// out. We just need to pass a non-nil error.
 		//
 		// This can also happen when updateAddrs is called during a connection
 		// attempt.
-		go newTr.Close(transport.ErrConnClosing)
+		newTr.Close(transport.ErrConnClosing)
 		return nil
 	}
+	defer ac.mu.Unlock()
 	if hctx.Err() != nil {
 		// onClose was already called for this connection, but the connection
 		// was successfully established first.  Consider it a success and set
@@ -1831,7 +1943,7 @@ func (cc *ClientConn) initAuthority() error {
 	} else if auth, ok := cc.resolverBuilder.(resolver.AuthorityOverrider); ok {
 		cc.authority = auth.OverrideAuthority(cc.parsedTarget)
 	} else if strings.HasPrefix(endpoint, ":") {
-		cc.authority = "localhost" + endpoint
+		cc.authority = "localhost" + encodeAuthority(endpoint)
 	} else {
 		cc.authority = encodeAuthority(endpoint)
 	}
@@ -44,8 +44,7 @@ type PerRPCCredentials interface {
 	// A54). uri is the URI of the entry point for the request.  When supported
 	// by the underlying implementation, ctx can be used for timeout and
 	// cancellation. Additionally, RequestInfo data will be available via ctx
-	// to this call.  TODO(zhaoq): Define the set of the qualified keys instead
-	// of leaving it as an arbitrary string.
+	// to this call.
 	GetRequestMetadata(ctx context.Context, uri ...string) (map[string]string, error)
 	// RequireTransportSecurity indicates whether the credentials requires
 	// transport security.
@@ -96,10 +95,11 @@ func (c CommonAuthInfo) GetCommonAuthInfo() CommonAuthInfo {
 	return c
 }

-// ProtocolInfo provides information regarding the gRPC wire protocol version,
-// security protocol, security protocol version in use, server name, etc.
+// ProtocolInfo provides static information regarding transport credentials.
 type ProtocolInfo struct {
 	// ProtocolVersion is the gRPC wire protocol version.
+	//
+	// Deprecated: this is unused by gRPC.
 	ProtocolVersion string
 	// SecurityProtocol is the security protocol in use.
 	SecurityProtocol string
@@ -109,7 +109,16 @@ type ProtocolInfo struct {
 	//
 	// Deprecated: please use Peer.AuthInfo.
 	SecurityVersion string
-	// ServerName is the user-configured server name.
+	// ServerName is the user-configured server name.  If set, this overrides
+	// the default :authority header used for all RPCs on the channel using the
+	// containing credentials, unless grpc.WithAuthority is set on the channel,
+	// in which case that setting will take precedence.
+	//
+	// This must be a valid `:authority` header according to
+	// [RFC3986](https://datatracker.ietf.org/doc/html/rfc3986#section-3.2).
+	//
+	// Deprecated: Users should use grpc.WithAuthority to override the authority
+	// on a channel instead of configuring the credentials.
 	ServerName string
 }

@@ -173,12 +182,17 @@ type TransportCredentials interface {
 	// Clone makes a copy of this TransportCredentials.
 	Clone() TransportCredentials
 	// OverrideServerName specifies the value used for the following:
+	//
 	// - verifying the hostname on the returned certificates
 	// - as SNI in the client's handshake to support virtual hosting
 	// - as the value for `:authority` header at stream creation time
 	//
-	// Deprecated: use grpc.WithAuthority instead. Will be supported
-	// throughout 1.x.
+	// The provided string should be a valid `:authority` header according to
+	// [RFC3986](https://datatracker.ietf.org/doc/html/rfc3986#section-3.2).
+	//
+	// Deprecated: this method is unused by gRPC.  Users should use
+	// grpc.WithAuthority to override the authority on a channel instead of
+	// configuring the credentials.
 	OverrideServerName(string) error
 }

@@ -56,9 +56,13 @@ func (t TLSInfo) AuthType() string {
 // non-nil error if the validation fails.
 func (t TLSInfo) ValidateAuthority(authority string) error {
 	var errs []error
+	host, _, err := net.SplitHostPort(authority)
+	if err != nil {
+		host = authority
+	}
 	for _, cert := range t.State.PeerCertificates {
 		var err error
-		if err = cert.VerifyHostname(authority); err == nil {
+		if err = cert.VerifyHostname(host); err == nil {
 			return nil
 		}
 		errs = append(errs, err)
@@ -110,14 +114,14 @@ func (c tlsCreds) Info() ProtocolInfo {
 func (c *tlsCreds) ClientHandshake(ctx context.Context, authority string, rawConn net.Conn) (_ net.Conn, _ AuthInfo, err error) {
 	// use local cfg to avoid clobbering ServerName if using multiple endpoints
 	cfg := credinternal.CloneTLSConfig(c.config)
-	if cfg.ServerName == "" {
-		serverName, _, err := net.SplitHostPort(authority)
-		if err != nil {
-			// If the authority had no host port or if the authority cannot be parsed, use it as-is.
-			serverName = authority
-		}
-		cfg.ServerName = serverName
+
+	serverName, _, err := net.SplitHostPort(authority)
+	if err != nil {
+		// If the authority had no host port or if the authority cannot be parsed, use it as-is.
+		serverName = authority
 	}
+	cfg.ServerName = serverName
+
 	conn := tls.Client(rawConn, cfg)
 	errChannel := make(chan error, 1)
 	go func() {
@@ -259,9 +263,11 @@ func applyDefaults(c *tls.Config) *tls.Config {
 // certificates to establish the identity of the client need to be included in
 // the credentials (eg: for mTLS), use NewTLS instead, where a complete
 // tls.Config can be specified.
-// serverNameOverride is for testing only. If set to a non empty string,
-// it will override the virtual host name of authority (e.g. :authority header
-// field) in requests.
+//
+// serverNameOverride is for testing only. If set to a non empty string, it will
+// override the virtual host name of authority (e.g. :authority header field) in
+// requests.  Users should use grpc.WithAuthority passed to grpc.NewClient to
+// override the authority of the client instead.
 func NewClientTLSFromCert(cp *x509.CertPool, serverNameOverride string) TransportCredentials {
 	return NewTLS(&tls.Config{ServerName: serverNameOverride, RootCAs: cp})
 }
@@ -271,9 +277,11 @@ func NewClientTLSFromCert(cp *x509.CertPool, serverNameOverride string) Transpor
 // certificates to establish the identity of the client need to be included in
 // the credentials (eg: for mTLS), use NewTLS instead, where a complete
 // tls.Config can be specified.
-// serverNameOverride is for testing only. If set to a non empty string,
-// it will override the virtual host name of authority (e.g. :authority header
-// field) in requests.
+//
+// serverNameOverride is for testing only. If set to a non empty string, it will
+// override the virtual host name of authority (e.g. :authority header field) in
+// requests.  Users should use grpc.WithAuthority passed to grpc.NewClient to
+// override the authority of the client instead.
 func NewClientTLSFromFile(certFile, serverNameOverride string) (TransportCredentials, error) {
 	b, err := os.ReadFile(certFile)
 	if err != nil {
@@ -608,6 +608,8 @@ func WithChainStreamInterceptor(interceptors ...StreamClientInterceptor) DialOpt

 // WithAuthority returns a DialOption that specifies the value to be used as the
 // :authority pseudo-header and as the server name in authentication handshake.
+// This overrides all other ways of setting authority on the channel, but can be
+// overridden per-call by using grpc.CallAuthority.
 func WithAuthority(a string) DialOption {
 	return newFuncDialOption(func(o *dialOptions) {
 		o.authority = a
@@ -27,8 +27,10 @@ package encoding

 import (
 	"io"
+	"slices"
 	"strings"

+	"google.golang.org/grpc/encoding/internal"
 	"google.golang.org/grpc/internal/grpcutil"
 )

@@ -36,12 +38,26 @@ import (
 // It is intended for grpc internal use only.
 const Identity = "identity"

+func init() {
+	internal.RegisterCompressorForTesting = func(c Compressor) func() {
+		name := c.Name()
+		curCompressor, found := registeredCompressor[name]
+		RegisterCompressor(c)
+		return func() {
+			if found {
+				registeredCompressor[name] = curCompressor
+				return
+			}
+			delete(registeredCompressor, name)
+			grpcutil.RegisteredCompressorNames = slices.DeleteFunc(grpcutil.RegisteredCompressorNames, func(s string) bool {
+				return s == name
+			})
+		}
+	}
+}
+
 // Compressor is used for compressing and decompressing when sending or
 // receiving messages.
-//
-// If a Compressor implements `DecompressedSize(compressedBytes []byte) int`,
-// gRPC will invoke it to determine the size of the buffer allocated for the
-// result of decompression.  A return value of -1 indicates unknown size.
 type Compressor interface {
 	// Compress writes the data written to wc to w after compressing it.  If an
 	// error occurs while initializing the compressor, that error is returned
@@ -0,0 +1,28 @@
+/*
+ *
+ * Copyright 2025 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package internal contains code internal to the encoding package.
+package internal
+
+// RegisterCompressorForTesting registers a compressor in the global compressor
+// registry. It returns a cleanup function that should be called at the end
+// of the test to unregister the compressor.
+//
+// This prevents compressors registered in one test from appearing in the
+// encoding headers of subsequent tests.
+var RegisterCompressorForTesting any // func RegisterCompressor(c Compressor) func()
@@ -46,9 +46,25 @@ func (c *codecV2) Marshal(v any) (data mem.BufferSlice, err error) {
 		return nil, fmt.Errorf("proto: failed to marshal, message is %T, want proto.Message", v)
 	}

+	// Important: if we remove this Size call then we cannot use
+	// UseCachedSize in MarshalOptions below.
 	size := proto.Size(vv)
+
+	// MarshalOptions with UseCachedSize allows reusing the result from the
+	// previous Size call. This is safe here because:
+	//
+	// 1. We just computed the size.
+	// 2. We assume the message is not being mutated concurrently.
+	//
+	// Important: If the proto.Size call above is removed, using UseCachedSize
+	// becomes unsafe and may lead to incorrect marshaling.
+	//
+	// For more details, see the doc of UseCachedSize:
+	// https://pkg.go.dev/google.golang.org/protobuf/proto#MarshalOptions
+	marshalOptions := proto.MarshalOptions{UseCachedSize: true}
+
 	if mem.IsBelowBufferPoolingThreshold(size) {
-		buf, err := proto.Marshal(vv)
+		buf, err := marshalOptions.Marshal(vv)
 		if err != nil {
 			return nil, err
 		}
@@ -56,7 +72,7 @@ func (c *codecV2) Marshal(v any) (data mem.BufferSlice, err error) {
 	} else {
 		pool := mem.DefaultBufferPool()
 		buf := pool.Get(size)
-		if _, err := (proto.MarshalOptions{}).MarshalAppend((*buf)[:0], vv); err != nil {
+		if _, err := marshalOptions.MarshalAppend((*buf)[:0], vv); err != nil {
 			pool.Put(buf)
 			return nil, err
 		}
@@ -75,6 +75,8 @@ const (
 	MetricTypeIntHisto
 	MetricTypeFloatHisto
 	MetricTypeIntGauge
+	MetricTypeIntUpDownCount
+	MetricTypeIntAsyncGauge
 )

 // Int64CountHandle is a typed handle for a int count metric. This handle
@@ -93,6 +95,23 @@ func (h *Int64CountHandle) Record(recorder MetricsRecorder, incr int64, labels .
 	recorder.RecordInt64Count(h, incr, labels...)
 }

+// Int64UpDownCountHandle is a typed handle for an int up-down counter metric.
+// This handle is passed at the recording point in order to know which metric
+// to record on.
+type Int64UpDownCountHandle MetricDescriptor
+
+// Descriptor returns the int64 up-down counter handle typecast to a pointer to a
+// MetricDescriptor.
+func (h *Int64UpDownCountHandle) Descriptor() *MetricDescriptor {
+	return (*MetricDescriptor)(h)
+}
+
+// Record records the int64 up-down counter value on the metrics recorder provided.
+// The value 'v' can be positive to increment or negative to decrement.
+func (h *Int64UpDownCountHandle) Record(recorder MetricsRecorder, v int64, labels ...string) {
+	recorder.RecordInt64UpDownCount(h, v, labels...)
+}
+
 // Float64CountHandle is a typed handle for a float count metric. This handle is
 // passed at the recording point in order to know which metric to record on.
 type Float64CountHandle MetricDescriptor
@@ -154,6 +173,30 @@ func (h *Int64GaugeHandle) Record(recorder MetricsRecorder, incr int64, labels .
 	recorder.RecordInt64Gauge(h, incr, labels...)
 }

+// AsyncMetric is a marker interface for asynchronous metric types.
+type AsyncMetric interface {
+	isAsync()
+	Descriptor() *MetricDescriptor
+}
+
+// Int64AsyncGaugeHandle is a typed handle for an int gauge metric. This handle is
+// passed at the recording point in order to know which metric to record on.
+type Int64AsyncGaugeHandle MetricDescriptor
+
+// isAsync implements the AsyncMetric interface.
+func (h *Int64AsyncGaugeHandle) isAsync() {}
+
+// Descriptor returns the int64 gauge handle typecast to a pointer to a
+// MetricDescriptor.
+func (h *Int64AsyncGaugeHandle) Descriptor() *MetricDescriptor {
+	return (*MetricDescriptor)(h)
+}
+
+// Record records the int64 gauge value on the metrics recorder provided.
+func (h *Int64AsyncGaugeHandle) Record(recorder AsyncMetricsRecorder, value int64, labels ...string) {
+	recorder.RecordInt64AsyncGauge(h, value, labels...)
+}
+
 // registeredMetrics are the registered metric descriptor names.
 var registeredMetrics = make(map[string]bool)

@@ -249,6 +292,35 @@ func RegisterInt64Gauge(descriptor MetricDescriptor) *Int64GaugeHandle {
 	return (*Int64GaugeHandle)(descPtr)
 }

+// RegisterInt64UpDownCount registers the metric description onto the global registry.
+// It returns a typed handle to use for recording data.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe. If multiple metrics are
+// registered with the same name, this function will panic.
+func RegisterInt64UpDownCount(descriptor MetricDescriptor) *Int64UpDownCountHandle {
+	registerMetric(descriptor.Name, descriptor.Default)
+	// Set the specific metric type for the up-down counter
+	descriptor.Type = MetricTypeIntUpDownCount
+	descPtr := &descriptor
+	metricsRegistry[descriptor.Name] = descPtr
+	return (*Int64UpDownCountHandle)(descPtr)
+}
+
+// RegisterInt64AsyncGauge registers the metric description onto the global registry.
+// It returns a typed handle to use for recording data.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe. If multiple metrics are
+// registered with the same name, this function will panic.
+func RegisterInt64AsyncGauge(descriptor MetricDescriptor) *Int64AsyncGaugeHandle {
+	registerMetric(descriptor.Name, descriptor.Default)
+	descriptor.Type = MetricTypeIntAsyncGauge
+	descPtr := &descriptor
+	metricsRegistry[descriptor.Name] = descPtr
+	return (*Int64AsyncGaugeHandle)(descPtr)
+}
+
 // snapshotMetricsRegistryForTesting snapshots the global data of the metrics
 // registry. Returns a cleanup function that sets the metrics registry to its
 // original state.
@@ -19,9 +19,13 @@
 // Package stats contains experimental metrics/stats API's.
 package stats

-import "google.golang.org/grpc/stats"
+import (
+	"google.golang.org/grpc/internal"
+	"google.golang.org/grpc/stats"
+)

 // MetricsRecorder records on metrics derived from metric registry.
+// Implementors must embed UnimplementedMetricsRecorder.
 type MetricsRecorder interface {
 	// RecordInt64Count records the measurement alongside labels on the int
 	// count associated with the provided handle.
@@ -38,6 +42,49 @@ type MetricsRecorder interface {
 	// RecordInt64Gauge records the measurement alongside labels on the int
 	// gauge associated with the provided handle.
 	RecordInt64Gauge(handle *Int64GaugeHandle, incr int64, labels ...string)
+	// RecordInt64UpDownCounter records the measurement alongside labels on the int
+	// count associated with the provided handle.
+	RecordInt64UpDownCount(handle *Int64UpDownCountHandle, incr int64, labels ...string)
+	// RegisterAsyncReporter registers a reporter to produce metric values for
+	// only the listed descriptors. The returned function must be called when
+	// the metrics are no longer needed, which will remove the reporter. The
+	// returned method needs to be idempotent and concurrent safe.
+	RegisterAsyncReporter(reporter AsyncMetricReporter, descriptors ...AsyncMetric) func()
+
+	// EnforceMetricsRecorderEmbedding is included to force implementers to embed
+	// another implementation of this interface, allowing gRPC to add methods
+	// without breaking users.
+	internal.EnforceMetricsRecorderEmbedding
+}
+
+// AsyncMetricReporter is an interface for types that record metrics asynchronously
+// for the set of descriptors they are registered with. The AsyncMetricsRecorder
+// parameter is used to record values for these metrics.
+//
+// Implementations must make unique recordings across all registered
+// AsyncMetricReporters. Meaning, they should not report values for a metric with
+// the same attributes as another AsyncMetricReporter will report.
+//
+// Implementations must be concurrent-safe.
+type AsyncMetricReporter interface {
+	// Report records metric values using the provided recorder.
+	Report(AsyncMetricsRecorder) error
+}
+
+// AsyncMetricReporterFunc is an adapter to allow the use of ordinary functions as
+// AsyncMetricReporters.
+type AsyncMetricReporterFunc func(AsyncMetricsRecorder) error
+
+// Report calls f(r).
+func (f AsyncMetricReporterFunc) Report(r AsyncMetricsRecorder) error {
+	return f(r)
+}
+
+// AsyncMetricsRecorder records on asynchronous metrics derived from metric registry.
+type AsyncMetricsRecorder interface {
+	// RecordInt64AsyncGauge records the measurement alongside labels on the int
+	// count associated with the provided handle asynchronously
+	RecordInt64AsyncGauge(handle *Int64AsyncGaugeHandle, incr int64, labels ...string)
 }

 // Metrics is an experimental legacy alias of the now-stable stats.MetricSet.
@@ -52,3 +99,33 @@ type Metric = string
 func NewMetrics(metrics ...Metric) *Metrics {
 	return stats.NewMetricSet(metrics...)
 }
+
+// UnimplementedMetricsRecorder must be embedded to have forward compatible implementations.
+type UnimplementedMetricsRecorder struct {
+	internal.EnforceMetricsRecorderEmbedding
+}
+
+// RecordInt64Count provides a no-op implementation.
+func (UnimplementedMetricsRecorder) RecordInt64Count(*Int64CountHandle, int64, ...string) {}
+
+// RecordFloat64Count provides a no-op implementation.
+func (UnimplementedMetricsRecorder) RecordFloat64Count(*Float64CountHandle, float64, ...string) {}
+
+// RecordInt64Histo provides a no-op implementation.
+func (UnimplementedMetricsRecorder) RecordInt64Histo(*Int64HistoHandle, int64, ...string) {}
+
+// RecordFloat64Histo provides a no-op implementation.
+func (UnimplementedMetricsRecorder) RecordFloat64Histo(*Float64HistoHandle, float64, ...string) {}
+
+// RecordInt64Gauge provides a no-op implementation.
+func (UnimplementedMetricsRecorder) RecordInt64Gauge(*Int64GaugeHandle, int64, ...string) {}
+
+// RecordInt64UpDownCount provides a no-op implementation.
+func (UnimplementedMetricsRecorder) RecordInt64UpDownCount(*Int64UpDownCountHandle, int64, ...string) {
+}
+
+// RegisterAsyncReporter provides a no-op implementation.
+func (UnimplementedMetricsRecorder) RegisterAsyncReporter(AsyncMetricReporter, ...AsyncMetric) func() {
+	// No-op: Return an empty function to ensure caller doesn't panic on nil function call
+	return func() {}
+}
@@ -97,8 +97,12 @@ type StreamServerInfo struct {
 	IsServerStream bool
 }

-// StreamServerInterceptor provides a hook to intercept the execution of a streaming RPC on the server.
-// info contains all the information of this RPC the interceptor can operate on. And handler is the
-// service method implementation. It is the responsibility of the interceptor to invoke handler to
-// complete the RPC.
+// StreamServerInterceptor provides a hook to intercept the execution of a
+// streaming RPC on the server.
+//
+// srv is the service implementation on which the RPC was invoked, and needs to
+// be passed to handler, and not used otherwise. ss is the server side of the
+// stream. info contains all the information of this RPC the interceptor can
+// operate on. And handler is the service method implementation. It is the
+// responsibility of the interceptor to invoke handler to complete the RPC.
 type StreamServerInterceptor func(srv any, ss ServerStream, info *StreamServerInfo, handler StreamHandler) error
@@ -67,6 +67,10 @@ type Balancer struct {
 	// balancerCurrent before the UpdateSubConnState is called on the
 	// balancerCurrent.
 	currentMu sync.Mutex
+
+	// activeGoroutines tracks all the goroutines that this balancer has started
+	// and that should be waited on when the balancer closes.
+	activeGoroutines sync.WaitGroup
 }

 // swap swaps out the current lb with the pending lb and updates the ClientConn.
@@ -76,7 +80,9 @@ func (gsb *Balancer) swap() {
 	cur := gsb.balancerCurrent
 	gsb.balancerCurrent = gsb.balancerPending
 	gsb.balancerPending = nil
+	gsb.activeGoroutines.Add(1)
 	go func() {
+		defer gsb.activeGoroutines.Done()
 		gsb.currentMu.Lock()
 		defer gsb.currentMu.Unlock()
 		cur.Close()
@@ -274,6 +280,7 @@ func (gsb *Balancer) Close() {

 	currentBalancerToClose.Close()
 	pendingBalancerToClose.Close()
+	gsb.activeGoroutines.Wait()
 }

 // balancerWrapper wraps a balancer.Balancer, and overrides some Balancer
@@ -324,7 +331,12 @@ func (bw *balancerWrapper) UpdateState(state balancer.State) {
 	defer bw.gsb.mu.Unlock()
 	bw.lastState = state

+	// If Close() acquires the mutex before UpdateState(), the balancer
+	// will already have been removed from the current or pending state when
+	// reaching this point.
 	if !bw.gsb.balancerCurrentOrPending(bw) {
+		// Returning here ensures that (*Balancer).swap() is not invoked after
+		// (*Balancer).Close() and therefore prevents "use after close".
 		return
 	}

@@ -0,0 +1,66 @@
+/*
+ *
+ * Copyright 2025 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package weight contains utilities to manage endpoint weights. Weights are
+// used by LB policies such as ringhash to distribute load across multiple
+// endpoints.
+package weight
+
+import (
+	"fmt"
+
+	"google.golang.org/grpc/resolver"
+)
+
+// attributeKey is the type used as the key to store EndpointInfo in the
+// Attributes field of resolver.Endpoint.
+type attributeKey struct{}
+
+// EndpointInfo will be stored in the Attributes field of Endpoints in order to
+// use the ringhash balancer.
+type EndpointInfo struct {
+	Weight uint32
+}
+
+// Equal allows the values to be compared by Attributes.Equal.
+func (a EndpointInfo) Equal(o any) bool {
+	oa, ok := o.(EndpointInfo)
+	return ok && oa.Weight == a.Weight
+}
+
+// Set returns a copy of endpoint in which the Attributes field is updated with
+// EndpointInfo.
+func Set(endpoint resolver.Endpoint, epInfo EndpointInfo) resolver.Endpoint {
+	endpoint.Attributes = endpoint.Attributes.WithValue(attributeKey{}, epInfo)
+	return endpoint
+}
+
+// String returns a human-readable representation of EndpointInfo.
+// This method is intended for logging, testing, and debugging purposes only.
+// Do not rely on the output format, as it is not guaranteed to remain stable.
+func (a EndpointInfo) String() string {
+	return fmt.Sprintf("Weight: %d", a.Weight)
+}
+
+// FromEndpoint returns the EndpointInfo stored in the Attributes field of an
+// endpoint. It returns an empty EndpointInfo if attribute is not found.
+func FromEndpoint(endpoint resolver.Endpoint) EndpointInfo {
+	v := endpoint.Attributes.Value(attributeKey{})
+	ei, _ := v.(EndpointInfo)
+	return ei
+}
@@ -83,6 +83,7 @@ func (b *Unbounded) Load() {
 		default:
 		}
 	} else if b.closing && !b.closed {
+		b.closed = true
 		close(b.c)
 	}
 }
@@ -194,7 +194,7 @@ func (r RefChannelType) String() string {
 // If channelz is not turned ON, this will simply log the event descriptions.
 func AddTraceEvent(l grpclog.DepthLoggerV2, e Entity, depth int, desc *TraceEvent) {
 	// Log only the trace description associated with the bottom most entity.
-	d := fmt.Sprintf("[%s]%s", e, desc.Desc)
+	d := fmt.Sprintf("[%s] %s", e, desc.Desc)
 	switch desc.Severity {
 	case CtUnknown, CtInfo:
 		l.InfoDepth(depth+1, d)
@@ -26,31 +26,31 @@ import (
 )

 var (
-	// TXTErrIgnore is set if TXT errors should be ignored ("GRPC_GO_IGNORE_TXT_ERRORS" is not "false").
+	// EnableTXTServiceConfig is set if the DNS resolver should perform TXT
+	// lookups for service config ("GRPC_ENABLE_TXT_SERVICE_CONFIG" is not
+	// "false").
+	EnableTXTServiceConfig = boolFromEnv("GRPC_ENABLE_TXT_SERVICE_CONFIG", true)
+
+	// TXTErrIgnore is set if TXT errors should be ignored
+	// ("GRPC_GO_IGNORE_TXT_ERRORS" is not "false").
 	TXTErrIgnore = boolFromEnv("GRPC_GO_IGNORE_TXT_ERRORS", true)
+
 	// RingHashCap indicates the maximum ring size which defaults to 4096
 	// entries but may be overridden by setting the environment variable
 	// "GRPC_RING_HASH_CAP".  This does not override the default bounds
 	// checking which NACKs configs specifying ring sizes > 8*1024*1024 (~8M).
 	RingHashCap = uint64FromEnv("GRPC_RING_HASH_CAP", 4096, 1, 8*1024*1024)
+
 	// ALTSMaxConcurrentHandshakes is the maximum number of concurrent ALTS
 	// handshakes that can be performed.
 	ALTSMaxConcurrentHandshakes = uint64FromEnv("GRPC_ALTS_MAX_CONCURRENT_HANDSHAKES", 100, 1, 100)
+
 	// EnforceALPNEnabled is set if TLS connections to servers with ALPN disabled
 	// should be rejected. The HTTP/2 protocol requires ALPN to be enabled, this
 	// option is present for backward compatibility. This option may be overridden
 	// by setting the environment variable "GRPC_ENFORCE_ALPN_ENABLED" to "true"
 	// or "false".
 	EnforceALPNEnabled = boolFromEnv("GRPC_ENFORCE_ALPN_ENABLED", true)
-	// XDSFallbackSupport is the env variable that controls whether support for
-	// xDS fallback is turned on. If this is unset or is false, only the first
-	// xDS server in the list of server configs will be used.
-	XDSFallbackSupport = boolFromEnv("GRPC_EXPERIMENTAL_XDS_FALLBACK", true)
-	// NewPickFirstEnabled is set if the new pickfirst leaf policy is to be used
-	// instead of the exiting pickfirst implementation. This can be disabled by
-	// setting the environment variable "GRPC_EXPERIMENTAL_ENABLE_NEW_PICK_FIRST"
-	// to "false".
-	NewPickFirstEnabled = boolFromEnv("GRPC_EXPERIMENTAL_ENABLE_NEW_PICK_FIRST", true)

 	// XDSEndpointHashKeyBackwardCompat controls the parsing of the endpoint hash
 	// key from EDS LbEndpoint metadata. Endpoint hash keys can be disabled by
@@ -69,6 +69,41 @@ var (
 	// ALTSHandshakerKeepaliveParams is set if we should add the
 	// KeepaliveParams when dial the ALTS handshaker service.
 	ALTSHandshakerKeepaliveParams = boolFromEnv("GRPC_EXPERIMENTAL_ALTS_HANDSHAKER_KEEPALIVE_PARAMS", false)
+
+	// EnableDefaultPortForProxyTarget controls whether the resolver adds a default port 443
+	// to a target address that lacks one. This flag only has an effect when all of
+	// the following conditions are met:
+	//   - A connect proxy is being used.
+	//   - Target resolution is disabled.
+	//   - The DNS resolver is being used.
+	EnableDefaultPortForProxyTarget = boolFromEnv("GRPC_EXPERIMENTAL_ENABLE_DEFAULT_PORT_FOR_PROXY_TARGET", true)
+
+	// XDSAuthorityRewrite indicates whether xDS authority rewriting is enabled.
+	// This feature is defined in gRFC A81 and is enabled by setting the
+	// environment variable GRPC_EXPERIMENTAL_XDS_AUTHORITY_REWRITE to "true".
+	XDSAuthorityRewrite = boolFromEnv("GRPC_EXPERIMENTAL_XDS_AUTHORITY_REWRITE", false)
+
+	// PickFirstWeightedShuffling indicates whether weighted endpoint shuffling
+	// is enabled in the pick_first LB policy, as defined in gRFC A113. This
+	// feature can be disabled by setting the environment variable
+	// GRPC_EXPERIMENTAL_PF_WEIGHTED_SHUFFLING to "false".
+	PickFirstWeightedShuffling = boolFromEnv("GRPC_EXPERIMENTAL_PF_WEIGHTED_SHUFFLING", true)
+
+	// DisableStrictPathChecking indicates whether strict path checking is
+	// disabled. This feature can be disabled by setting the environment
+	// variable GRPC_GO_EXPERIMENTAL_DISABLE_STRICT_PATH_CHECKING to "true".
+	//
+	// When strict path checking is enabled, gRPC will reject requests with
+	// paths that do not conform to the gRPC over HTTP/2 specification found at
+	// https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md.
+	//
+	// When disabled, gRPC will allow paths that do not contain a leading slash.
+	// Enabling strict path checking is recommended for security reasons, as it
+	// prevents potential path traversal vulnerabilities.
+	//
+	// A future release will remove this environment variable, enabling strict
+	// path checking behavior unconditionally.
+	DisableStrictPathChecking = boolFromEnv("GRPC_GO_EXPERIMENTAL_DISABLE_STRICT_PATH_CHECKING", false)
 )

 func boolFromEnv(envVar string, def bool) bool {
@@ -68,4 +68,15 @@ var (
 	// trust.  For more details, see:
 	// https://github.com/grpc/proposal/blob/master/A87-mtls-spiffe-support.md
 	XDSSPIFFEEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_MTLS_SPIFFE", false)
+
+	// XDSHTTPConnectEnabled is true if gRPC should parse custom Metadata
+	// configuring use of an HTTP CONNECT proxy via xDS from cluster resources.
+	// For more details, see:
+	// https://github.com/grpc/proposal/blob/master/A86-xds-http-connect.md
+	XDSHTTPConnectEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_HTTP_CONNECT", false)
+
+	// XDSBootstrapCallCredsEnabled controls if call credentials can be used in
+	// xDS bootstrap configuration via the `call_creds` field. For more details,
+	// see: https://github.com/grpc/proposal/blob/master/A97-xds-jwt-call-creds.md
+	XDSBootstrapCallCredsEnabled = boolFromEnv("GRPC_EXPERIMENTAL_XDS_BOOTSTRAP_CALL_CREDS", false)
 )
@@ -25,4 +25,11 @@ var (
 	// BufferPool is implemented by the grpc package and returns a server
 	// option to configure a shared buffer pool for a grpc.Server.
 	BufferPool any // func (grpc.SharedBufferPool) grpc.ServerOption
+
+	// SetDefaultBufferPool updates the default buffer pool.
+	SetDefaultBufferPool any // func(mem.BufferPool)
+
+	// AcceptCompressors is implemented by the grpc package and returns
+	// a call option that restricts the grpc-accept-encoding header for a call.
+	AcceptCompressors any // func(...string) grpc.CallOption
 )
@@ -80,25 +80,11 @@ func (cs *CallbackSerializer) ScheduleOr(f func(ctx context.Context), onFailure
 func (cs *CallbackSerializer) run(ctx context.Context) {
 	defer close(cs.done)

-	// TODO: when Go 1.21 is the oldest supported version, this loop and Close
-	// can be replaced with:
-	//
-	// context.AfterFunc(ctx, cs.callbacks.Close)
-	for ctx.Err() == nil {
-		select {
-		case <-ctx.Done():
-			// Do nothing here. Next iteration of the for loop will not happen,
-			// since ctx.Err() would be non-nil.
-		case cb := <-cs.callbacks.Get():
-			cs.callbacks.Load()
-			cb.(func(context.Context))(ctx)
-		}
-	}
+	// Close the buffer when the context is canceled
+	// to prevent new callbacks from being added.
+	context.AfterFunc(ctx, cs.callbacks.Close)

-	// Close the buffer to prevent new callbacks from being added.
-	cs.callbacks.Close()
-
-	// Run all pending callbacks.
+	// Run all callbacks.
 	for cb := range cs.callbacks.Get() {
 		cs.callbacks.Load()
 		cb.(func(context.Context))(ctx)
@@ -21,7 +21,6 @@
 package idle

 import (
-	"fmt"
 	"math"
 	"sync"
 	"sync/atomic"
@@ -33,15 +32,15 @@ var timeAfterFunc = func(d time.Duration, f func()) *time.Timer {
 	return time.AfterFunc(d, f)
 }

-// Enforcer is the functionality provided by grpc.ClientConn to enter
-// and exit from idle mode.
-type Enforcer interface {
-	ExitIdleMode() error
+// ClientConn is the functionality provided by grpc.ClientConn to enter and exit
+// from idle mode.
+type ClientConn interface {
+	ExitIdleMode()
 	EnterIdleMode()
 }

-// Manager implements idleness detection and calls the configured Enforcer to
-// enter/exit idle mode when appropriate.  Must be created by NewManager.
+// Manager implements idleness detection and calls the ClientConn to enter/exit
+// idle mode when appropriate. Must be created by NewManager.
 type Manager struct {
 	// State accessed atomically.
 	lastCallEndTime           int64 // Unix timestamp in nanos; time when the most recent RPC completed.
@@ -51,8 +50,8 @@ type Manager struct {

 	// Can be accessed without atomics or mutex since these are set at creation
 	// time and read-only after that.
-	enforcer Enforcer // Functionality provided by grpc.ClientConn.
-	timeout  time.Duration
+	cc      ClientConn // Functionality provided by grpc.ClientConn.
+	timeout time.Duration

 	// idleMu is used to guarantee mutual exclusion in two scenarios:
 	// - Opposing intentions:
@@ -72,9 +71,9 @@ type Manager struct {

 // NewManager creates a new idleness manager implementation for the
 // given idle timeout.  It begins in idle mode.
-func NewManager(enforcer Enforcer, timeout time.Duration) *Manager {
+func NewManager(cc ClientConn, timeout time.Duration) *Manager {
 	return &Manager{
-		enforcer:         enforcer,
+		cc:               cc,
 		timeout:          timeout,
 		actuallyIdle:     true,
 		activeCallsCount: -math.MaxInt32,
@@ -127,7 +126,7 @@ func (m *Manager) handleIdleTimeout() {

 	// Now that we've checked that there has been no activity, attempt to enter
 	// idle mode, which is very likely to succeed.
-	if m.tryEnterIdleMode() {
+	if m.tryEnterIdleMode(true) {
 		// Successfully entered idle mode. No timer needed until we exit idle.
 		return
 	}
@@ -142,10 +141,13 @@ func (m *Manager) handleIdleTimeout() {
 // that, it performs a last minute check to ensure that no new RPC has come in,
 // making the channel active.
 //
+// checkActivity controls if a check for RPC activity, since the last time the
+// idle_timeout fired, is made.
+
 // Return value indicates whether or not the channel moved to idle mode.
 //
 // Holds idleMu which ensures mutual exclusion with exitIdleMode.
-func (m *Manager) tryEnterIdleMode() bool {
+func (m *Manager) tryEnterIdleMode(checkActivity bool) bool {
 	// Setting the activeCallsCount to -math.MaxInt32 indicates to OnCallBegin()
 	// that the channel is either in idle mode or is trying to get there.
 	if !atomic.CompareAndSwapInt32(&m.activeCallsCount, 0, -math.MaxInt32) {
@@ -166,7 +168,7 @@ func (m *Manager) tryEnterIdleMode() bool {
 		atomic.AddInt32(&m.activeCallsCount, math.MaxInt32)
 		return false
 	}
-	if atomic.LoadInt32(&m.activeSinceLastTimerCheck) == 1 {
+	if checkActivity && atomic.LoadInt32(&m.activeSinceLastTimerCheck) == 1 {
 		// A very short RPC could have come in (and also finished) after we
 		// checked for calls count and activity in handleIdleTimeout(), but
 		// before the CAS operation. So, we need to check for activity again.
@@ -177,44 +179,37 @@ func (m *Manager) tryEnterIdleMode() bool {
 	// No new RPCs have come in since we set the active calls count value to
 	// -math.MaxInt32. And since we have the lock, it is safe to enter idle mode
 	// unconditionally now.
-	m.enforcer.EnterIdleMode()
+	m.cc.EnterIdleMode()
 	m.actuallyIdle = true
 	return true
 }

 // EnterIdleModeForTesting instructs the channel to enter idle mode.
 func (m *Manager) EnterIdleModeForTesting() {
-	m.tryEnterIdleMode()
+	m.tryEnterIdleMode(false)
 }

 // OnCallBegin is invoked at the start of every RPC.
-func (m *Manager) OnCallBegin() error {
+func (m *Manager) OnCallBegin() {
 	if m.isClosed() {
-		return nil
+		return
 	}

 	if atomic.AddInt32(&m.activeCallsCount, 1) > 0 {
 		// Channel is not idle now. Set the activity bit and allow the call.
 		atomic.StoreInt32(&m.activeSinceLastTimerCheck, 1)
-		return nil
+		return
 	}

 	// Channel is either in idle mode or is in the process of moving to idle
 	// mode. Attempt to exit idle mode to allow this RPC.
-	if err := m.ExitIdleMode(); err != nil {
-		// Undo the increment to calls count, and return an error causing the
-		// RPC to fail.
-		atomic.AddInt32(&m.activeCallsCount, -1)
-		return err
-	}
-
+	m.ExitIdleMode()
 	atomic.StoreInt32(&m.activeSinceLastTimerCheck, 1)
-	return nil
 }

-// ExitIdleMode instructs m to call the enforcer's ExitIdleMode and update m's
+// ExitIdleMode instructs m to call the ClientConn's ExitIdleMode and update its
 // internal state.
-func (m *Manager) ExitIdleMode() error {
+func (m *Manager) ExitIdleMode() {
 	// Holds idleMu which ensures mutual exclusion with tryEnterIdleMode.
 	m.idleMu.Lock()
 	defer m.idleMu.Unlock()
@@ -231,12 +226,10 @@ func (m *Manager) ExitIdleMode() error {
 		//   m.ExitIdleMode.
 		//
 		// In any case, there is nothing to do here.
-		return nil
+		return
 	}

-	if err := m.enforcer.ExitIdleMode(); err != nil {
-		return fmt.Errorf("failed to exit idle mode: %w", err)
-	}
+	m.cc.ExitIdleMode()

 	// Undo the idle entry process. This also respects any new RPC attempts.
 	atomic.AddInt32(&m.activeCallsCount, math.MaxInt32)
@@ -244,7 +237,23 @@ func (m *Manager) ExitIdleMode() error {

 	// Start a new timer to fire after the configured idle timeout.
 	m.resetIdleTimerLocked(m.timeout)
-	return nil
+}
+
+// UnsafeSetNotIdle instructs the Manager to update its internal state to
+// reflect the reality that the channel is no longer in IDLE mode.
+//
+// N.B. This method is intended only for internal use by the gRPC client
+// when it exits IDLE mode **manually** from `Dial`. The callsite must ensure:
+//   - The channel was **actually in IDLE mode** immediately prior to the call.
+//   - There is **no concurrent activity** that could cause the channel to exit
+//     IDLE mode *naturally* at the same time.
+func (m *Manager) UnsafeSetNotIdle() {
+	m.idleMu.Lock()
+	defer m.idleMu.Unlock()
+
+	atomic.AddInt32(&m.activeCallsCount, math.MaxInt32)
+	m.actuallyIdle = false
+	m.resetIdleTimerLocked(m.timeout)
 }

 // OnCallEnd is invoked at the end of every RPC.
@@ -182,35 +182,6 @@ var (
 	// other features, including the CSDS service.
 	NewXDSResolverWithClientForTesting any // func(xdsclient.XDSClient) (resolver.Builder, error)

-	// RegisterRLSClusterSpecifierPluginForTesting registers the RLS Cluster
-	// Specifier Plugin for testing purposes, regardless of the XDSRLS environment
-	// variable.
-	//
-	// TODO: Remove this function once the RLS env var is removed.
-	RegisterRLSClusterSpecifierPluginForTesting func()
-
-	// UnregisterRLSClusterSpecifierPluginForTesting unregisters the RLS Cluster
-	// Specifier Plugin for testing purposes. This is needed because there is no way
-	// to unregister the RLS Cluster Specifier Plugin after registering it solely
-	// for testing purposes using RegisterRLSClusterSpecifierPluginForTesting().
-	//
-	// TODO: Remove this function once the RLS env var is removed.
-	UnregisterRLSClusterSpecifierPluginForTesting func()
-
-	// RegisterRBACHTTPFilterForTesting registers the RBAC HTTP Filter for testing
-	// purposes, regardless of the RBAC environment variable.
-	//
-	// TODO: Remove this function once the RBAC env var is removed.
-	RegisterRBACHTTPFilterForTesting func()
-
-	// UnregisterRBACHTTPFilterForTesting unregisters the RBAC HTTP Filter for
-	// testing purposes. This is needed because there is no way to unregister the
-	// HTTP Filter after registering it solely for testing purposes using
-	// RegisterRBACHTTPFilterForTesting().
-	//
-	// TODO: Remove this function once the RBAC env var is removed.
-	UnregisterRBACHTTPFilterForTesting func()
-
 	// ORCAAllowAnyMinReportingInterval is for examples/orca use ONLY.
 	ORCAAllowAnyMinReportingInterval any // func(so *orca.ServiceOptions)

@@ -240,22 +211,11 @@ var (
 	// default resolver scheme.
 	UserSetDefaultScheme = false

-	// ConnectedAddress returns the connected address for a SubConnState. The
-	// address is only valid if the state is READY.
-	ConnectedAddress any // func (scs SubConnState) resolver.Address
-
-	// SetConnectedAddress sets the connected address for a SubConnState.
-	SetConnectedAddress any // func(scs *SubConnState, addr resolver.Address)
-
 	// SnapshotMetricRegistryForTesting snapshots the global data of the metric
 	// registry. Returns a cleanup function that sets the metric registry to its
 	// original state. Only called in testing functions.
 	SnapshotMetricRegistryForTesting func() func()

-	// SetDefaultBufferPoolForTesting updates the default buffer pool, for
-	// testing purposes.
-	SetDefaultBufferPoolForTesting any // func(mem.BufferPool)
-
 	// SetBufferPoolingThresholdForTesting updates the buffer pooling threshold, for
 	// testing purposes.
 	SetBufferPoolingThresholdForTesting any // func(int)
@@ -273,6 +233,18 @@ var (
 	// When set, the function will be called before the stream enters
 	// the blocking state.
 	NewStreamWaitingForResolver = func() {}
+
+	// AddressToTelemetryLabels is an xDS-provided function to extract telemetry
+	// labels from a resolver.Address. Callers must assert its type before calling.
+	AddressToTelemetryLabels any // func(addr resolver.Address) map[string]string
+
+	// AsyncReporterCleanupDelegate is initialized to a pass-through function by
+	// default (production behavior), allowing tests to swap it with an
+	// implementation which tracks registration of async reporter and its
+	// corresponding cleanup.
+	AsyncReporterCleanupDelegate = func(cleanup func()) func() {
+		return cleanup
+	}
 )

 // HealthChecker defines the signature of the client-side LB channel health
@@ -320,3 +292,9 @@ type EnforceClientConnEmbedding interface {
 type Timer interface {
 	Stop() bool
 }