loopd: write the next epoch from a compaction summary

Co-Authored-By: ornith-1.5-35b-a3b <agent@wntrmute.dev>

crates/loopd/tests/compact_advance.rs

@@ -0,0 +1,201 @@
+//! Tests for writing the next epoch. Do not edit.
+
+mod support;
+
+use bxcore::{Epoch, LogRecord, SessionId};
+use loopd::baseline::Baseline;
+use loopd::compact;
+use loopd::memory::{MemorySource, NoMemory};
+use loopd::session::Session;
+use loopd::tools::Registry;
+use support::Home;
+
+struct Block(&'static str);
+
+impl MemorySource for Block {
+    fn block(&self) -> Result<String, String> {
+        Ok(self.0.to_string())
+    }
+    fn updated(&self, _session: &SessionId, _turn: u64) -> Result<(), String> {
+        Ok(())
+    }
+}
+
+fn id(s: &str) -> SessionId {
+    SessionId::new(s).unwrap()
+}
+
+fn session(home: &Home) -> (loopd::config::Config, Session) {
+    let cfg = home.config(std::path::Path::new("/tmp/unused.sock"));
+    let baseline = Baseline::assemble(&cfg, &Registry::m2b()).unwrap();
+    let s = Session::create(&home.dir, id("a"), baseline, cfg.slots.main).unwrap();
+    (cfg, s)
+}
+
+#[test]
+fn commit_writes_epoch_end_a_new_baseline_and_a_new_log() {
+    let home = Home::new();
+    let (cfg, mut s) = session(&home);
+    s.append(LogRecord::User {
+        time: bxcore::Timestamp::parse("2026-09-18T08:00:00.000Z").unwrap(),
+        content: "hi".to_string(),
+        speaker: None,
+    })
+    .unwrap();
+    compact::commit(
+        &mut s,
+        &cfg,
+        &Registry::m2b(),
+        &NoMemory,
+        "the sum".to_string(),
+    )
+    .unwrap();
+
+    assert_eq!(s.epoch(), Epoch(1));
+    assert_eq!(s.carry(), Some("the sum"));
+    assert_eq!(s.slot(), cfg.slots.main);
+    assert_eq!(s.turns(), 1, "the old user still counts");
+    assert_eq!(
+        s.records()
+            .iter()
+            .filter(|r| matches!(r, LogRecord::User { .. }))
+            .count(),
+        0
+    );
+
+    let old = home.records("a");
+    assert!(
+        matches!(old.last(), Some(LogRecord::EpochEnd { next, summary, .. }) if *next == Epoch(1) && summary == "the sum")
+    );
+    assert!(home.dir.join("sessions/a/1.baseline.json").is_file());
+    let new_log = home.read("sessions/a/1.jsonl");
+    assert!(new_log.contains("\"epoch\":1"), "{new_log}");
+}
+
+#[test]
+fn the_new_baseline_takes_a_fresh_memory_block() {
+    let home = Home::new();
+    let (cfg, mut s) = session(&home);
+    compact::commit(
+        &mut s,
+        &cfg,
+        &Registry::m2b(),
+        &Block("I take my tea strong."),
+        "sum".to_string(),
+    )
+    .unwrap();
+    assert!(
+        s.baseline().system.contains("I take my tea strong."),
+        "{}",
+        s.baseline().system
+    );
+    let on_disk = home.read("sessions/a/1.baseline.json");
+    assert!(on_disk.contains("I take my tea strong."), "{on_disk}");
+}
+
+#[test]
+fn reopen_loads_the_new_epoch() {
+    let home = Home::new();
+    let (cfg, mut s) = session(&home);
+    compact::commit(
+        &mut s,
+        &cfg,
+        &Registry::m2b(),
+        &NoMemory,
+        "carry".to_string(),
+    )
+    .unwrap();
+    drop(s);
+    let s = Session::open(&home.dir, id("a")).unwrap();
+    assert_eq!(s.epoch(), Epoch(1));
+    assert_eq!(s.carry(), Some("carry"));
+}
+
+#[test]
+fn a_second_commit_does_not_write_another_epoch_end_on_the_old_log() {
+    let home = Home::new();
+    let (cfg, mut s) = session(&home);
+    compact::commit(
+        &mut s,
+        &cfg,
+        &Registry::m2b(),
+        &NoMemory,
+        "first".to_string(),
+    )
+    .unwrap();
+    let ends = home
+        .records("a")
+        .iter()
+        .filter(|r| matches!(r, LogRecord::EpochEnd { .. }))
+        .count();
+    assert_eq!(ends, 1);
+    compact::commit(
+        &mut s,
+        &cfg,
+        &Registry::m2b(),
+        &NoMemory,
+        "second".to_string(),
+    )
+    .unwrap();
+    assert_eq!(s.epoch(), Epoch(2));
+    let ends = home
+        .records("a")
+        .iter()
+        .filter(|r| matches!(r, LogRecord::EpochEnd { .. }))
+        .count();
+    assert_eq!(ends, 1, "epoch 0 still has one EpochEnd");
+    let mid = home.read("sessions/a/1.jsonl");
+    assert!(mid.contains("\"type\":\"epoch_end\""), "{mid}");
+}
+
+#[test]
+fn resume_after_epoch_end_without_next_files_does_not_write_a_second_end() {
+    let home = Home::new();
+    let (cfg, mut s) = session(&home);
+    s.append(LogRecord::EpochEnd {
+        time: bxcore::Timestamp::now(),
+        next: Epoch(1),
+        summary: "already".to_string(),
+    })
+    .unwrap();
+    drop(s);
+    let mut s = Session::open(&home.dir, id("a")).unwrap();
+    assert_eq!(s.epoch(), Epoch(0));
+    compact::commit(
+        &mut s,
+        &cfg,
+        &Registry::m2b(),
+        &NoMemory,
+        "ignored".to_string(),
+    )
+    .unwrap();
+    let ends = home
+        .records("a")
+        .iter()
+        .filter(|r| matches!(r, LogRecord::EpochEnd { .. }))
+        .count();
+    assert_eq!(ends, 1);
+    assert_eq!(s.epoch(), Epoch(1));
+    assert_eq!(
+        s.carry(),
+        Some("already"),
+        "the summary already in EpochEnd is the carry"
+    );
+}
+
+#[test]
+fn the_new_session_start_keeps_the_live_slot() {
+    let home = Home::new();
+    let cfg = home.config(std::path::Path::new("/tmp/unused.sock"));
+    let baseline = Baseline::assemble(&cfg, &Registry::m2b()).unwrap();
+    let mut s = Session::create(&home.dir, id("a"), baseline, 7).unwrap();
+    compact::commit(&mut s, &cfg, &Registry::m2b(), &NoMemory, "s".to_string()).unwrap();
+    assert_eq!(s.slot(), 7);
+    match &s.records()[0] {
+        LogRecord::SessionStart { slot, epoch, .. } => {
+            assert_eq!(*slot, 7);
+            assert_eq!(*epoch, Epoch(1));
+        }
+        other => panic!("{other:?}"),
+    }
+}