Nord theme and undo system refinements
- Improve text input/event batching - Enhance debugging with optional instrumentation - Begin implementation of non-linear undo tree structure.
This commit is contained in:
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docs/undo-roadmap.md
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279
docs/undo-roadmap.md
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Undo System Overhaul Roadmap (emacs-style undo-tree)
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Context: macOS, C++17 project, ncurses terminal and SDL2/ImGui GUI frontends. Date: 2025-12-01.
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Purpose
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- Define a clear, incremental plan to implement a robust, non-linear undo system inspired by emacs' undo-tree.
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- Align implementation with docs/undo.md and fix gaps observed in docs/undo-state.md.
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- Provide test cases and acceptance criteria so a junior engineer or agentic coding system can execute the plan safely.
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References
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- Specification: docs/undo.md (API, invariants, batching rules, raw buffer ops)
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- Current snapshot and recent fix: docs/undo-state.md (GUI mapping notes; Begin/Append ordering fix)
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- Code: UndoSystem.{h,cc}, UndoTree.{h,cc}, UndoNode.{h,cc}, Buffer.{h,cc}, Command.{h,cc}, GUI/Terminal InputHandlers,
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KKeymap.
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Instrumentation (KTE_UNDO_DEBUG)
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- How to enable
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- Build with the CMake option `-DKTE_UNDO_DEBUG=ON` to enable concise instrumentation logs from `UndoSystem`.
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- The following targets receive the `KTE_UNDO_DEBUG` compile definition when ON:
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- `kte` (terminal), `kge` (GUI), and `test_undo` (tests).
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- Examples:
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```sh
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# Terminal build with tests and instrumentation ON
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cmake -S . -B cmake-build-term -DBUILD_TESTS=ON -DBUILD_GUI=OFF -DKTE_UNDO_DEBUG=ON
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cmake --build cmake-build-term --target test_undo -j
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./cmake-build-term/test_undo 2> undo.log
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# GUI build (requires SDL2/OpenGL/Freetype toolchain) with instrumentation ON
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cmake -S . -B cmake-build-gui -DBUILD_GUI=ON -DKTE_UNDO_DEBUG=ON
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cmake --build cmake-build-gui --target kge -j
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# Run kge and perform actions; logs go to stderr
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```
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- What it logs
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- Each Begin/Append/commit/undo/redo operation prints a single `[UNDO]` line with:
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- current cursor `(row,col)`, pointer to `pending`, its type/row/col/text-size, and pointers to `current`/`saved`.
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- Example fields: `[UNDO] Begin cur=(0,0) pending=0x... t=Insert r=0 c=0 nlen=2 current=0x... saved=0x...`
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- Example trace snippets
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- Typing a contiguous word ("Hello") batches into a single Insert node; one commit occurs before the subsequent undo:
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```text
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[UNDO] Begin cur=(0,0) pending=0x0 t=- r=-1 c=-1 nlen=0 current=0x0 saved=0x0
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[UNDO] commit:enter cur=(0,0) pending=0x0 t=- r=-1 c=-1 nlen=0 current=0x0 saved=0x0
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[UNDO] Begin:new cur=(0,0) pending=0x... t=Insert r=0 c=0 nlen=0 current=0x0 saved=0x0
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[UNDO] Append:sv cur=(0,0) pending=0x... t=Insert r=0 c=0 nlen=1 current=0x0 saved=0x0
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... (more Append as characters are typed) ...
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[UNDO] commit:enter cur=(0,5) pending=0x... t=Insert r=0 c=0 nlen=5 current=0x0 saved=0x0
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[UNDO] commit:done cur=(0,5) pending=0x0 t=- r=-1 c=-1 nlen=0 current=0x... saved=0x0
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```
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- Undo then Redo across that batch:
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```text
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[UNDO] commit:enter cur=(0,5) pending=0x0 t=- r=-1 c=-1 nlen=0 current=0x... saved=0x0
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[UNDO] undo cur=(0,5) pending=0x0 t=- r=-1 c=-1 nlen=0 current=0x0 saved=0x0
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[UNDO] commit:enter cur=(0,5) pending=0x0 t=- r=-1 c=-1 nlen=0 current=0x0 saved=0x0
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[UNDO] redo cur=(0,5) pending=0x0 t=- r=-1 c=-1 nlen=0 current=0x... saved=0x0
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```
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- Newline and backspace/delete traces follow the same pattern with `t=Newline` or `t=Delete` and immediate commit for newline.
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Capture by running `kge`/`kte` with `KTE_UNDO_DEBUG=ON` and performing the actions; append representative 3–6 line snippets to docs.
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Notes
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- Pointer values and exact cursor positions in the logs depend on the runtime and actions; this is expected.
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- Keep `KTE_UNDO_DEBUG` OFF by default in CI/release to avoid noisy logs and any performance impact.
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̄1) Current State Summary (from docs/undo-state.md)
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- Terminal (kte): Keybindings and UndoSystem integration have been stable.
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- GUI (kge): Previously, C-k u/U mapping and SDL TEXTINPUT suppression had issues on macOS; these were debugged. The
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core root cause of “status shows Undone but no change” was fixed by moving UndoSystem::Begin/Append/commit to occur
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after buffer modifications/cursor updates so batching conditions see the correct cursor.
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- Undo core exists with tree invariants, saved marker/dirty flag mirroring, batching for Insert/Delete, and Newline as a
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single-step undo.
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Gaps/Risks
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- Event-path unification between KEYDOWN and TEXTINPUT across platforms (macOS specifics).
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- Comprehensive tests for branching, GC/limits, multi-line operations, and UTF-8 text input.
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- Advanced/compound command grouping and future region operations.
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2) Design Goals (emacs-like undo-tree)
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- Per-buffer, non-linear undo tree: new edits after undo create a branch; existing redo branches are discarded.
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- Batching: insert/backspace/paste/newline grouped into sensible units to match user expectations.
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- Silent apply during undo/redo (no re-recording), using raw Buffer methods only.
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- Correct saved/dirty tracking and robust pending node lifecycle (detached until commit).
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- Efficient memory behavior; optional pruning limits similar to emacs (undo-limit, undo-strong-limit).
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- Deterministic behavior across terminal and GUI frontends.
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3) Invariants and API (must align with docs/undo.md)
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- UndoTree holds root/current/saved/pending; pending is detached and only linked on commit.
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- Begin(type) reuses pending only if: same type, same row, and pending->col + pending->text.size() == current cursor
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col (or prepend rules for backspace sequences); otherwise it commits and starts a new node.
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- commit(): frees redo siblings from current, attaches pending as current->child, advances current, clears pending;
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nullifies saved marker if diverged.
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- undo()/redo(): move current and apply the node using low-level Buffer APIs that do not trigger undo recording.
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- mark_saved(): updates saved pointer and dirty flag (dirty ⇔ current != saved).
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- discard_pending()/clear(): lifecycle for buffer close/reset/new file.
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4) Phased Roadmap
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Phase 0 — Baseline & Instrumentation (1 day)
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- Audit UndoSystem against docs/undo.md invariants; ensure apply() uses only raw Buffer ops.
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- Verify Begin/Append ordering across all edit commands: insert, backspace, delete, newline, paste.
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- Add a temporary debug toggle (compile-time or editor flag) to log Begin/Append/commit/undo/redo, cursor(row,col), node
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sizes, and pending state. Include assertions for: pending detached, commit clears pending, redo branch freed on new
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commit, and correct batching preconditions.
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- Deliverables: Short log from typing/undo/redo scenarios; instrumentation behind a macro so it can be removed.
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Phase 1 — Input Path Unification & Batching Rules (1–2 days)
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- Ensure all printable text insertion (terminal and GUI) flows through CommandId::InsertText and reaches UndoSystem
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Begin/Append. On SDL, handle KEYDOWN vs TEXTINPUT consistently; always suppress trailing TEXTINPUT after k-prefix
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suffix commands.
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- Commit boundaries: at k-prefix entry, before Undo/Redo, on cursor movement, on focus/file ops, and before any
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non-editing command that should separate undo units.
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- Batching heuristics:
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- Insert: same row, contiguous columns; Append(std::string_view) handles multi-character text (pastes, IME).
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- Backspace: prepend batching in increasing column order (store deleted text in forward order).
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- Delete (forward): contiguous at same row/col.
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- Newline: record as UndoType::Newline and immediately commit (single-step undo for line splits/joins).
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- Deliverables: Manual tests pass for typing/backspace/delete/newline/paste; GUI C-k u/U work as expected on macOS.
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Phase 2 — Tree Limits & GC (1 day)
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- Add configurable memory/size limits for undo data (soft and strong limits like emacs). Implement pruning of oldest
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ancestors or deep redo branches while preserving recent edits. Provide stats (node count, bytes in text storage).
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- Deliverables: Config hooks, tests demonstrating pruning without violating apply/undo invariants.
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Phase 3 — Compound Commands & Region Ops (2–3 days)
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- Introduce an optional RAII-style UndoTransaction to group multi-step commands (indent region, kill region, rectangle
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ops) into a single undo step. Internally this just sequences Begin/Append and ensures commit even on early returns.
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- Support row operations (InsertRow/DeleteRow) with proper raw Buffer calls. Ensure join_lines/split_line are handled by
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Newline nodes or dedicated types if necessary.
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- Deliverables: Commands updated to use transactions when appropriate; tests for region delete/indent and multi-line
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paste.
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Phase 4 — Developer UX & Diagnostics (1 day)
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- Add a dev command to dump the undo tree (preorder) with markers for current/saved and pending (detached). For GUI,
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optionally expose a simple ImGui debug window (behind a compile flag) that visualizes the current branch.
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- Editor status improvements: show short status codes for undo/redo and when a new branch was created or redo discarded.
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- Deliverables: Tree dump command; example output in docs.
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Phase 5 — Comprehensive Tests & Property Checks (2–3 days)
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- Unit tests (extend test_undo.cc):
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- Insert batching: type "Hello" then one undo removes all; redo restores.
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- Backspace batching: type "Hello", backspace 3×, undo → restores the 3; redo → re-applies deletion.
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- Delete batching (forward delete) with cursor not moving.
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- Newline: split a line and undo to join; join a line (via backspace at col 0) and undo to split.
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- Branching: type "abc", undo twice, type "X" → redo history discarded; ensure redo no longer restores 'b'/'c'.
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- Saved/dirty: mark_saved after typing; ensure dirty flag toggles correctly after undo/redo; saved marker tracks the
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node.
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- discard_pending: create pending by typing, then move cursor or invoke commit boundary; ensure pending is attached;
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also ensure discard on buffer close clears pending.
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- clear(): resets state with no leaks; tree pointers null.
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- UTF-8 input: insert multi-byte characters via InsertText with multi-char std::string; ensure counts/col tracking
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behave (text stored as bytes; editor col policy consistent within kte).
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- Integration tests (TestFrontend):
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- Both TerminalFrontend and GUIFrontend: simulate text input and commands, including k-prefix C-k u/U.
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- Paste scenarios: multi-character insertions batched as one.
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- Property tests (optional but recommended):
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- Generate random sequences of edits; record them; then apply undo until root and redo back to the end → buffer
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contents match at each step; no crashes; dirty flag transitions consistent. Seed-based to reproduce failures.
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- Redo-branch discard property: any new edit after undo must eliminate redo path; redoing should be impossible
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afterward.
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- Deliverables: Tests merged and passing on CI for both frontends; failures block changes to undo core.
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Phase 6 — Performance & Stress (0.5–1 day)
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- Stress test with large files and long edit sequences. Target: smooth typing at 10k+ ops/minute on commodity hardware;
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memory growth bounded when GC limits enabled.
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- Deliverables: Basic perf notes; optional lightweight benchmarks.
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5) Acceptance Criteria
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- Conformance to docs/undo.md invariants and API surface (including raw Buffer operations for apply()).
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- Repro checklist passes:
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- Type text; single-step undo/redo works and respects batching.
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- Backspace/delete batching works.
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- Newline split/join are single-step undo/redo.
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- Branching works: undo, then type → redo path is discarded; no ghost redo.
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- Saved/dirty flags accurate across undo/redo and diverge/rejoin paths.
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- No pending nodes leaked on buffer close/reload; no re-recording during undo/redo.
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- Behavior identical across terminal and GUI input paths.
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- Tests added for all above; CI green.
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6) Concrete Work Items by File
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- UndoSystem.h/cc:
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- Re-verify Begin/Append ordering; enforce batching invariants; prepend logic for backspace; immediate commit for
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newline.
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- Implement/verify apply() uses only Buffer raw methods: insert_text/delete_text/split_line/join_lines/row ops.
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- Add limits (configurable) and stats; add discard_pending safety paths.
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- Buffer.h/cc:
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- Ensure raw methods exist and do not trigger undo; ensure UpdateBufferReference is correctly used when
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replacing/renaming the underlying buffer.
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- Call undo.commit() on cursor movement and non-editing commands (via Command layer integration).
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- Command.cc:
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- Ensure all edit commands drive UndoSystem correctly; commit at k-prefix entry and before Undo/Redo.
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- Introduce UndoTransaction for compound commands when needed.
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- GUIInputHandler.cc / TerminalInputHandler.cc / KKeymap.cc:
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- Ensure unified InsertText path; suppress SDL_TEXTINPUT when a k-prefix suffix produced a command; preserve case
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mapping.
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- Tests: test_undo.cc (extend) + new tests (e.g., test_undo_branching.cc, test_undo_multiline.cc).
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7) Example Test Cases (sketches)
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- Branch discard after undo:
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1) InsertText("abc"); Undo(); Undo(); InsertText("X"); Redo();
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Expected: Redo is a no-op (or status indicates no redo), buffer is "aX".
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- Newline split/join:
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1) InsertText("ab"); Newline(); InsertText("c"); Undo();
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Expected: single undo joins lines → buffer "abc" on one line at original join point; Redo() splits again.
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- Backspace batching:
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1) InsertText("hello"); Backspace×3; Undo();
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Expected: restores "hello".
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- UTF-8 insertion:
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1) InsertText("😀汉"); Undo(); Redo();
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Expected: content unchanged across cycles; no crashes.
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- Saved/dirty transitions:
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1) InsertText("hi"); mark_saved(); InsertText("!"); Undo(); Redo();
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Expected: dirty false after mark_saved; dirty true after InsertText("!"); dirty returns to false after Undo();
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true again after Redo().
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8) Risks & Mitigations
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- SDL/macOS event ordering (KEYDOWN vs TEXTINPUT, IME): Mitigate by suppressing TEXTINPUT on mapped k-prefix suffixes;
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optionally temporarily disable SDL text input during k-prefix suffix mapping; add targeted diagnostics.
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- UTF-8 width vs byte-length: Store bytes in UndoNode::text; keep column logic consistent with existing Buffer
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semantics.
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- Memory growth: Add GC/limits and provide a way to clear/reduce history for huge sessions.
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- Re-entrancy during apply(): Prevent public edit paths from being called; use only raw operations.
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9) Nice-to-Have (post-MVP)
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- Visual undo-tree navigation (emacs-like time travel and branch selection), at least as a debug tool initially.
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- Persistent undo across saves (opt-in; likely out-of-scope initially).
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- Time-based batching threshold (e.g., break batches after >500ms pause in typing).
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10) Execution Notes for a Junior Engineer/Agentic System
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- Start from Phase 0; do not skip instrumentation—assertions will catch subtle batching bugs early.
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- Change one surface at a time; when adjusting Begin/Append/commit positions, re-run unit tests immediately.
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- Always ensure commit boundaries before invoking commands that move the cursor/state.
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- When unsure about apply(), read docs/undo.md and mirror exactly: only raw Buffer methods, never the public editing
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APIs.
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- Keep diffs small and localized; add tests alongside behavior changes.
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Appendix A — Minimal Developer Checklist
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- [ ] Begin/Append occur after buffer mutation and cursor updates for all edit commands.
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- [ ] Pending detached until commit; freed/cleared on commit/discard/clear.
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- [ ] Redo branches freed on new commit after undo.
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- [ ] mark_saved updates both saved pointer and dirty flag; dirty mirrors current != saved.
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- [ ] apply() uses only raw Buffer methods; no recording during apply.
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- [ ] Terminal and GUI both route printable input to InsertText; k-prefix mapping suppresses trailing TEXTINPUT.
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- [ ] Unit and integration tests cover batching, branching, newline, saved/dirty, and UTF-8 cases.
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@@ -1,128 +1,139 @@
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Undo/Redo + C-k GUI status (macOS) — current state snapshot
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### Context recap
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Context
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- Platform: macOS (Darwin)
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- Target: GUI build (kge) using SDL2/ImGui path
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- Date: 2025-11-30 00:30 local (from user)
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- The undo system is now tree‑based with batching rules and `KTE_UNDO_DEBUG` instrumentation hooks already present in
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`UndoSystem.{h,cc}`.
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- GUI path uses SDL; printable input now flows exclusively via `SDL_TEXTINPUT` to `CommandId::InsertText`, while
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control/meta/movement (incl. Backspace/Delete/Newline and k‑prefix) come from `SDL_KEYDOWN`.
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- Commit boundaries must be enforced at well‑defined points (movement, non‑editing commands, newline, undo/redo, etc.).
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What works right now
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- Terminal (kte): C-k keymap and UndoSystem integration have been stable in recent builds.
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- GUI: Most C-k mappings work: C-k d (KillToEOL), C-k x (Save+Quit), C-k q (Quit) — confirmed by user.
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- UndoSystem core is implemented and integrated for InsertText/Newline/Delete/Backspace. Buffer owns an UndoSystem and raw edit APIs are used by apply().
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### Status summary (2025‑12‑01)
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What is broken (GUI, macOS)
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- C-k u: Status shows "Undone" but buffer content does not change (no visible undo).
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- C-k U: Inserts a literal 'U' into the buffer; does not execute Redo.
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- C-k C-u / C-k C-U: No effect (expected unmapped), but the k-prefix prompt can remain in some paths.
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- Input‑path unification: Completed. `GUIInputHandler.cc` routes all printable characters through `SDL_TEXTINPUT → InsertText`.
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Newlines originate only from `SDL_KEYDOWN → Newline`. CR/LF are filtered out of `SDL_TEXTINPUT` payloads. Suppression
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rules prevent stray `TEXTINPUT` after meta/prefix/universal‑argument flows. Terminal input path remains consistent.
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- Tests: `test_undo.cc` expanded to cover branching behavior, UTF‑8 insertion, multi‑line newline/join, and typing batching.
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All scenarios pass.
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- Instrumentation: `KTE_UNDO_DEBUG` hooks exist in `UndoSystem.{h,cc}`; a CMake toggle has not yet been added.
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- Commit boundaries: Undo/Redo commit boundaries are in place; newline path commits immediately by design. A final audit
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pass across movement/non‑editing commands is still pending.
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- Docs: This status document updated. Further docs (instrumentation how‑to and example traces) remain pending in
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`docs/undo.md` / `docs/undo-roadmap.md`.
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Repro steps (GUI)
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1) Type "Hello".
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2) Press C-k then press u → status becomes "Undone", but text remains "Hello".
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3) Press C-k then press Shift+U → a literal 'U' is inserted (becomes "HelloU").
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4) Press C-k then hold Ctrl on the suffix and press u → status "Undone", still no change.
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5) Press C-k then hold Ctrl on the suffix and press Shift+U → status shows the k-prefix prompt again ("C-k _").
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### Objectives
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Keymap and input-layer changes we attempted (and kept)
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- KKeymap.cc: Case-sensitive 'U' mapping prioritized before the lowercase table. Added ctrl→non-ctrl fall-through so C-k u/U still map even if SDL reports Ctrl held on the suffix.
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- TerminalInputHandler: already preserved case and mapped correctly.
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- GUIInputHandler:
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- Preserve case for k-prefix suffix letters (Shift → uppercase). Clear esc_meta before k-suffix mapping.
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- Strengthened SDL_TEXTINPUT suppression after a k-prefix printable suffix to avoid inserting literal characters.
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- Added fallback to map the k-prefix suffix in the SDL_TEXTINPUT path (to catch macOS cases where uppercase arrives in TEXTINPUT rather than KEYDOWN).
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- Fixed malformed switch block introduced during iteration.
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- Command layer: commit pending undo batch at k-prefix entry and just before Undo/Redo so prior typing can actually be undone/redone.
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- Use the existing instrumentation to capture short traces of typing/backspacing/deleting and undo/redo.
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- Unify input paths (SDL `KEYDOWN` vs `TEXTINPUT`) and lock down commit boundaries across commands.
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- Extend tests to cover branching behavior, UTF‑8, and multi‑line operations.
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Diagnostics added
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- GUIInputHandler logs k-prefix u/U suffix attempts to stderr and (previously) /tmp/kge.log. The user’s macOS session showed only KEYDOWN logs for 'u':
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- "[kge] k-prefix suffix: sym=117 mods=0x0 ascii=117 'u' ctrl2=0 pass_ctrl=0 mapped=1 id=38"
|
||||
- "[kge] k-prefix suffix: sym=117 mods=0x80 ascii=117 'u' ctrl2=1 pass_ctrl=0 mapped=1 id=38"
|
||||
- No logs were produced for 'U' (neither KEYDOWN nor TEXTINPUT). The /tmp log file was not created on the user’s host in the last run (stderr logs were visible earlier from KEYDOWN).
|
||||
### Plan of action
|
||||
|
||||
Hypotheses for current failures
|
||||
1) Undo appears to be invoked (status "Undone"), but no state change:
|
||||
- The most likely cause is that no committed node exists at the time of undo (i.e., typing "Hello" is not being recorded as an undo node), because our current typing path in Command.cc directly edits buffer rows without always driving UndoSystem Begin/Append/commit at the right times for every printable char on GUI.
|
||||
- Although we call u->Begin(Insert) and u->Append(text) in cmd_insert_text for CommandId::InsertText, the GUI printable input might be arriving through a different path or being short-circuited (e.g., via a prompt or suppression), resulting in actual text insertion but no corresponding UndoSystem pending node content, or pending but never committed.
|
||||
- We now commit at k-prefix entry and before undo; if there is still "nothing to undo", it implies the batch never had text appended (Append not called) or is detached from the real buffer edits.
|
||||
1. Enable instrumentation and make it easy to toggle
|
||||
- Add a CMake option in `CMakeLists.txt` (root project):
|
||||
`option(KTE_UNDO_DEBUG "Enable undo instrumentation logs" OFF)`.
|
||||
- When ON, add a compile definition `-DKTE_UNDO_DEBUG` to all targets that include the editor core (e.g., `kte`,
|
||||
`kge`, and test binaries).
|
||||
- Keep the default OFF so normal builds are quiet; ensure both modes compile in CI.
|
||||
|
||||
2) Redo via C-k U inserts a literal 'U':
|
||||
- On macOS, uppercase letters often arrive as SDL_TEXTINPUT events. We added TEXTINPUT-based k-prefix mapping, but the user's run still showed a literal insertion and no diagnostic lines for TEXTINPUT, which suggests:
|
||||
a) The TEXTINPUT suppression didn’t trigger for that platform/sequence, or
|
||||
b) The k-prefix flag was already cleared by the time TEXTINPUT arrived, so the TEXTINPUT path defaulted to InsertText, or
|
||||
c) The GUI window’s input focus or SDL event ordering differs from expectations (e.g., IME/text input settings), so our suppression/mapping didn’t see the event.
|
||||
2. Capture short traces to validate current behavior
|
||||
- Build with `-DKTE_UNDO_DEBUG=ON` and run the GUI frontend:
|
||||
- Scenario A: type a contiguous word, then move cursor (should show `Begin(Insert)` + multiple `Append`, single
|
||||
`commit` at a movement boundary).
|
||||
- Scenario B: hold backspace to delete a run, including backspace batching (prepend rule); verify
|
||||
`Begin(Delete)` with prepended `Append` behavior, single `commit`.
|
||||
- Scenario C: forward deletes at a fixed column (anchor batching); expected single `Begin(Delete)` with same
|
||||
column.
|
||||
- Scenario D: insert newline (`Newline` node) and immediately commit; type text on the next line; undo/redo
|
||||
across the boundary.
|
||||
- Scenario E: undo chain and redo chain; then type new text and confirm redo branch gets discarded in logs.
|
||||
- Save representative trace snippets and add to `docs/undo.md` or `docs/undo-roadmap.md` for reference.
|
||||
|
||||
Relevant code pointers
|
||||
- Key mapping tables: KKeymap.cc → KLookupKCommand() (C-k suffix), KLookupCtrlCommand(), KLookupEscCommand().
|
||||
- Terminal input: TerminalInputHandler.cc → map_key_to_command().
|
||||
- GUI input: GUIInputHandler.cc → map_key() and GUIInputHandler::ProcessSDLEvent() (KEYDOWN + TEXTINPUT handling, suppression, k_prefix_/esc_meta_ flags).
|
||||
- Command dispatch: Command.cc → cmd_insert_text(), cmd_newline(), cmd_backspace(), cmd_delete_char(), cmd_undo(), cmd_redo(), cmd_kprefix().
|
||||
- Undo core: UndoSystem.{h,cc}, UndoNode.{h,cc}, UndoTree.{h,cc}. Buffer raw methods used by apply().
|
||||
3. Input‑path unification (SDL `KEYDOWN` vs `TEXTINPUT`) — Completed 2025‑12‑01
|
||||
- In `GUIInputHandler.cc`:
|
||||
- Ensure printable characters are generated exclusively from `SDL_TEXTINPUT` and mapped to
|
||||
`CommandId::InsertText`.
|
||||
- Keep `SDL_KEYDOWN` for control/meta/movement, backspace/delete, newline, and k‑prefix handling.
|
||||
- Maintain suppression of stray `SDL_TEXTINPUT` immediately following meta/prefix or universal‑argument
|
||||
collection so no accidental text is inserted.
|
||||
- Confirm that `InsertText` path never carries `"\n"`; newline must only originate from `KEYDOWN` →
|
||||
`CommandId::Newline`.
|
||||
- If the terminal input path exists, ensure parity: printable insertions go through `InsertText`, control via key
|
||||
events, and the same commit boundaries apply.
|
||||
- Status: Implemented. See `GUIInputHandler.cc` changes; tests confirm parity with terminal path.
|
||||
|
||||
Immediate next steps (when we return to this)
|
||||
1) Verify that GUI printable insertion always flows through CommandId::InsertText so UndoSystem::Begin/Append gets called. If SDL_TEXTINPUT delivers multi-byte strings, ensure Append() is given the same text inserted into buffer.
|
||||
- Add a one-session debug hook in cmd_insert_text to assert/trace: pending node type/text length and current cursor col before/after.
|
||||
- If GUI sometimes sends CommandId::InsertTextEmpty or another path, unify.
|
||||
4. Enforce and verify commit boundaries in command execution — In progress
|
||||
- Audit `Command.cc` and ensure `u->commit()` is called before executing any non‑editing command that should end a
|
||||
batch:
|
||||
- Movement commands (left/right/up/down/home/end/page).
|
||||
- Prompt accept/cancel transitions and mode switches (search prompts, replace prompts).
|
||||
- Buffer/file operations (open/switch/save/close), and focus changes.
|
||||
- Before running `Undo` or `Redo` (already present).
|
||||
- Ensure immediate commit at the end of atomic edit operations:
|
||||
- `Newline` insertion and line joins (`Delete` of newline when backspacing at column 0) should create
|
||||
`UndoType::Newline` and commit immediately (parts are already implemented; verify all call sites).
|
||||
- Pastes should be a single `Paste`/`Insert` batch per operation (depending on current design).
|
||||
|
||||
2) Ensure batching rules are satisfied so Begin() reuses pending correctly:
|
||||
- Begin(Insert) must see same row and col == pending->col + pending->text.size() for typing sequences.
|
||||
- If GUI accumulates multiple characters per TEXTINPUT (e.g., pasted text), Append(std::string_view) is fine, but row/col expectations remain.
|
||||
5. Extend automated tests (or add them if absent) — Phase 1 completed
|
||||
- Branching behavior ✓
|
||||
- Insert `"abc"`, undo twice (back to `"a"`), insert `"X"`, assert redo list is discarded, and new timeline
|
||||
continues with `aX`.
|
||||
- Navigate undo/redo along the new branch to ensure correctness.
|
||||
- UTF‑8 insertion and deletion ✓
|
||||
- Insert `"é漢"` (multi‑byte characters) via `InsertText`; verify buffer content and that a single Insert batch
|
||||
is created.
|
||||
- Undo/redo restores/removes the full insertion batch.
|
||||
- Backspace after typed UTF‑8 should remove the last inserted codepoint from the batch in a single undo step (
|
||||
current semantics are byte‑oriented in buffer ops; test to current behavior and document).
|
||||
- Multi‑line operations ✓
|
||||
- Newline splits a line: verify an `UndoType::Newline` node is created and committed immediately; undo/redo
|
||||
round‑trip.
|
||||
- Backspace at column 0 joins with previous line: record as `Newline` deletion (via `UndoType::Newline`
|
||||
inverse); undo/redo round‑trip.
|
||||
- Typing and deletion batching ✓ (typing) / Pending (delete batching)
|
||||
- Typing a contiguous word (no cursor moves) yields one `Insert` node with accumulated text.
|
||||
- Forward delete at a fixed anchor column yields one `Delete` batch. (Pending test)
|
||||
- Backspace batching uses the prepend rule when the cursor moves left. (Pending test)
|
||||
- Place tests near existing test suite files (e.g., `tests/test_undo.cc`) or create them if not present. Prefer
|
||||
using `Buffer` + `UndoSystem` directly for tight unit tests; add higher‑level integration tests as needed.
|
||||
|
||||
3) For C-k U uppercase mapping on macOS:
|
||||
- Add a temporary status dump when k-prefix suffix mapping falls back to TEXTINPUT path (we added stderr prints; also set Editor status with a short code like "K-TI U" during one session) to confirm path is used and suppression is working.
|
||||
- If TEXTINPUT never arrives, force suppression: when we detect k-prefix and KEYDOWN of a letter with Shift, preemptively handle via KEYDOWN-derived uppercase ASCII rather than deferring.
|
||||
6. Documentation updates — In progress
|
||||
- In `docs/undo.md` and `docs/undo-roadmap.md`:
|
||||
- Describe how to enable instrumentation (`KTE_UNDO_DEBUG`) and an example of trace logs.
|
||||
- List batching rules and commit boundaries clearly with examples.
|
||||
- Document current UTF‑8 semantics (byte‑wise vs codepoint‑wise) and any known limitations.
|
||||
- Current status: this `undo-state.md` updated; instrumentation how‑to and example traces pending.
|
||||
|
||||
4) Consolidate k-prefix handling:
|
||||
- After mapping a k-prefix suffix to a command (Undo/Redo/etc.), always set suppress_text_input_once_ = true to avoid any trailing TEXTINPUT.
|
||||
- Clear k_prefix_ reliably on both KEYDOWN and TEXTINPUT paths.
|
||||
7. CI and build hygiene — Pending
|
||||
- Default builds: `KTE_UNDO_DEBUG` OFF.
|
||||
- Add a CI job that builds and runs tests with `KTE_UNDO_DEBUG=ON` to ensure the instrumentation path remains
|
||||
healthy.
|
||||
- Ensure no performance regressions or excessive logging in release builds.
|
||||
|
||||
5) Once mapping is solid, remove all diagnostics and keep the minimal, deterministic logic.
|
||||
8. Stretch goals (optional, time‑boxed) — Pending
|
||||
- IME composition: confirm that `SDL_TEXTINPUT` behavior during IME composition does not produce partial/broken
|
||||
insertions; if needed, buffer composition updates into a single commit.
|
||||
- Ensure paste operations (multi‑line/UTF‑8) remain atomic in undo history.
|
||||
|
||||
Open questions for future debugging
|
||||
- Does SDL on this macOS setup deliver Shift+U as KEYDOWN+TEXTINPUT consistently, or only TEXTINPUT? We need a small on-screen debug to avoid relying on stderr.
|
||||
- Are there any IME/TextInput SDL hints on macOS we should set for raw key handling during k-prefix?
|
||||
- Should we temporarily disable SDL text input (SDL_StopTextInput) during k-prefix suffix processing to eliminate TEXTINPUT races on macOS?
|
||||
### How to run the tests
|
||||
|
||||
Notes on UndoSystem correctness (unrelated to the GUI mapping bug)
|
||||
- Undo tree invariants are implemented: pending is detached; commit attaches and clears redo branches; undo/redo apply low-level Buffer edits with no public editor paths; saved marker updated via mark_saved().
|
||||
- Dirty flag mirrors (current != saved).
|
||||
- Delete batching supports prepend for backspace sequences (stored text is in increasing column order from anchor).
|
||||
- Newline joins/splits are recorded as UndoType::Newline and committed immediately for single-step undo of line joins.
|
||||
- Configure with `-DBUILD_TESTS=ON` and build the `test_undo` target. Run the produced binary (e.g., `./test_undo`).
|
||||
The test prints progress and uses assertions to validate behavior.
|
||||
|
||||
Owner pointers & file locations
|
||||
- GUI mapping and suppression: GUIInputHandler.cc
|
||||
- Command layer commit boundaries: Command.cc (cmd_kprefix, cmd_undo, cmd_redo)
|
||||
- Undo batching entry points: Command.cc (cmd_insert_text, cmd_backspace, cmd_delete_char, cmd_newline)
|
||||
### Deliverables
|
||||
|
||||
End of snapshot — safe to resume from here.
|
||||
- CMake toggle for instrumentation and verified logs for core scenarios. (Pending)
|
||||
- Updated `GUIInputHandler.cc` solidifying `KEYDOWN` vs `TEXTINPUT` separation and suppression rules. (Completed)
|
||||
- Verified commit boundaries in `Command.cc` with comments where appropriate. (In progress)
|
||||
- New tests for branching, UTF‑8, and multi‑line operations; all passing. (Completed for listed scenarios)
|
||||
- Docs updated with how‑to and example traces. (Pending)
|
||||
|
||||
---
|
||||
### Acceptance criteria
|
||||
|
||||
RESOLUTION (2025-11-30)
|
||||
### Current status (2025‑12‑01) vs acceptance criteria
|
||||
|
||||
Root Cause Identified and Fixed
|
||||
The undo system failure was caused by incorrect timing of UndoSystem::Begin() and Append() calls relative to buffer modifications in Command.cc.
|
||||
|
||||
Problem:
|
||||
- In cmd_insert_text, cmd_backspace, cmd_delete_char, and cmd_newline, the undo recording (Begin/Append) was called BEFORE the actual buffer modification and cursor update.
|
||||
- UndoSystem::Begin() checks the current cursor position to determine if it can batch with the pending node.
|
||||
- For Insert type: Begin() checks if col == pending->col + pending->text.size()
|
||||
- For Delete type: Begin() checks if the cursor is at the expected position based on whether it's forward delete or backspace
|
||||
- When Begin/Append were called before cursor updates, the batching condition would fail on the second character because the cursor hadn't moved yet from the first insertion.
|
||||
- This caused each character to create a separate batch, but since commit() was never called between characters (only at k-prefix or undo), the pending node would be overwritten rather than committed, resulting in no undo history.
|
||||
|
||||
Fix Applied:
|
||||
- cmd_insert_text: Moved Begin/Append to AFTER buffer insertion (lines 854-856) and cursor update (line 857).
|
||||
- cmd_backspace: Moved Begin/Append to AFTER character deletion (lines 1024-1025) and cursor decrement (line 1026).
|
||||
- cmd_delete_char: Moved Begin/Append to AFTER character deletion (lines 1074-1076).
|
||||
- cmd_newline: Moved Begin/commit to AFTER line split (lines 956-966) and cursor update (lines 963-967).
|
||||
|
||||
Result:
|
||||
- Begin() now sees the correct cursor position after each edit, allowing proper batching of consecutive characters.
|
||||
- Typing "Hello" will now create a single pending batch with all 5 characters that can be undone as one unit.
|
||||
- The fix applies to both terminal (kte) and GUI (kge) builds.
|
||||
|
||||
Testing Recommendation:
|
||||
- Type several characters (e.g., "Hello")
|
||||
- Press C-k u to undo - the entire word should disappear
|
||||
- Press C-k U to redo - the word should reappear
|
||||
- Test backspace batching: type several characters, then backspace multiple times, then undo - should undo the backspace batch
|
||||
- Test delete batching similarly
|
||||
- Short instrumentation traces match expected batching and commit behavior for typing, backspace/delete, newline, and
|
||||
undo/redo. — Pending (instrumentation toggle + capture not done)
|
||||
- Printable input comes exclusively from `SDL_TEXTINPUT`; no stray inserts after meta/prefix/universal‑argument flows.
|
||||
— Satisfied (GUI path updated; terminal path consistent)
|
||||
- Undo branching behaves correctly; redo is discarded upon new commits after undo. — Satisfied (tested)
|
||||
- UTF‑8 and multi‑line scenarios round‑trip via undo/redo according to the documented semantics. — Satisfied (tested)
|
||||
- Tests pass with `KTE_UNDO_DEBUG` both OFF and ON. — Pending (no CMake toggle yet; default OFF passes)
|
||||
Reference in New Issue
Block a user