l0ng-aiandClaude Opus 5 3fd523e1b9 feat(diff): make the sidebar diff preview optional and bound its cost ...

Clicking a sidebar row's `+N −N` opens the working-tree diff overlay. On a big
tree that could stall the window, and not everyone wants an in-app diff viewer
in the first place.

Two halves, matching the report.

The setting: `sidebar_diff_preview` (Settings → Window & Tabs, on by default,
persisted in `config.json`). Off, the branch and the counts stay exactly where
they are and read exactly the same; they lose only the pointer cursor and the
`toggle_diff_overlay` handler, so the press falls through to ordinary tab
activation. Both come off one value — `diff_click_cwd` — so they cannot get out
of step.

The performance work. All five of the reporter's hypotheses held up against
v26.7.6, and each fix is measured on a 300-file / 90 000-line / 4.5 MB diff
(release, macOS arm64):

1. The full diff was buffered before parsing — `git_status::git` uses
   `Command::output()`. Now streamed line by line through the new
   `git_status::git_lines` into an incremental `DiffParser`: peak transient
   buffer 4 552 060 bytes → 50 bytes, at ~1.7× the parse CPU (3.97 ms →
   6.76 ms) on the background thread, where it never touches a frame.

2. The snapshot was deep-cloned per holder inside `this.update`, i.e. on the
   UI thread. Now shared behind `Arc`: 2.41 ms → 11 ns per holder.

3. The element tree is not virtualized — confirmed, not cured. Rendering is not
   being redesigned here; instead the element count is bounded (see 4) and
   `MAX_RENDERED_FILES` caps the cards built at all, with a "… and N more" line
   for the tail.

4. Auto-collapse was per file, and counted only +/− while the rendered body
   also has context lines. Added `AUTO_COLLAPSE_TOTAL_LINES` over *retained*
   lines: sixty forty-line files, none individually large, went from 2400
   side-by-side rows to zero, under a summary saying the diff is too large to
   render efficiently and pointing at expanding individual files or `git diff`.

5. The Changes panel probed independently and kept its own snapshot. Both now
   go through `spawn_shared_diff_probe`, which dedupes by cwd and installs one
   `Arc` into every watcher; opening the overlay while the panel already shows
   that repo now paints from the panel's snapshot instead of re-probing.

Plus a repo-wide retention budget (`MAX_TOTAL_LINES`, `MAX_FILES_WITH_HUNKS`):
90 000 lines / 6.2 MiB of line text → 20 000 / 1.2 MiB. The `+N −N` totals
deliberately escape every cap — they are compared against `--numstat` to detect
staleness, so a capped total would disagree forever and re-probe in a loop.

Small diffs are untouched: a forty-file, twelve-lines-each tree is not
oversized and still opens expanded, asserted directly.

Not verified: anything requiring the GUI. No frame timings, no visual check of
the oversized banner or the settings row, and `AUTO_COLLAPSE_TOTAL_LINES` is a
judgement call anchored on row count rather than a measured frame budget.

Refs #239.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

2026-07-29 16:10:46 +08:00

..

tty7-core

feat(diff): make the sidebar diff preview optional and bound its cost

2026-07-29 16:10:46 +08:00

tty7-server

fix(workspaces): make a handover atomic and stop two stores clobbering one file

2026-07-28 21:54:23 +08:00