Recap — "Since main" git-status review view

Date: 2026-07-02 Relates to: adr/decisions/005-since-base-github-view-default-20260701-223706.md

What shipped

A composite since-base diff — merge-base(base, HEAD) vs the working tree plus untracked files — became the default code-review view, rendered as a three-section git-status panel (Committed / Changes / Untracked) with a Sections | Tree toggle, a first-run setup chooser, and a "baseline behind GitHub" fetch banner. Git only; Perforce/jj/workspace/PR modes untouched. Shared logic lives in packages/shared/review-core.ts and is mirrored across both server runtimes (Bun packages/server/review.ts, Pi apps/pi-extension/server/serverReview.ts).

Where the implementation diverged from the spec/ADR

These are deliberate implementation-time pivots — recorded so the ADR/spec aren't read as ground truth where they differ:

1. Sections sidecar carries no per-file status. The spec's files: Record<path, { group, status, staged }> shipped as { group, staged } only — the client already derives A/M/D/R from the patch itself.
2. No "Advanced" footer row in the Sections panel. Advanced diff modes live in the Tree view's DiffTypePicker dropdown; the header Sections | Tree toggle is the path between them. The Sections panel's only comparison control is the base row.
3. DiffTypeSetupDialog was removed, not extended. Replaced by the richer two-page ReviewSetupDialog (panel-view + diff-type chooser with screenshot previews), reached from a new "Set up review view" header-menu item.
4. Committed section is not opacity-muted. It renders at full weight, distinguished by the section header/grouping only.

Post-merge review round (2026-07-02)

A seven-agent review + the app's own PR review surfaced a batch of fixes, all landed on this branch:

• Sections rename parser split -> on the quoted token → a dirty file could show as Committed. Now quote-aware (splitPorcelainRename, unit-tested).
• /api/diff/switch epoch captured after await req.json() → a slow-body older request could overwrite a newer one. Epoch now captured before any await; hideWhitespace committed only on win. Both runtimes.
• Unresolvable base no longer auto-defaults to a degraded since-base — the default falls through to uncommitted. Fingerprint/file-content degrade to HEAD to match the diff/sections siblings.
• rm --cached no longer produces two diff entries for one path (untracked files already in the tracked patch are dropped) — fixes wrong-file-open and j/k nav looping in the Sections panel. Also fixes the latent uncommitted/unstaged cases.
• Settings' "Default Diff View" list now preserves the sections⟺since-base coupling.
• Banner only treats origin/* as fetchable; a bare local base ("main") is upgraded to its tracking ref at startup so Fetch can clear it.
• hashUntracked resolves untracked paths against the repo toplevel (was cwd) so a review launched from a subdirectory isn't blind to untracked edits.
• Agent review instruction now tells agents to enumerate/inspect untracked files.
• Terminology unified: one "Committed changes" label; the live "Since " label is dynamic (matches the header), "Since main" kept only as product copy.

Known limitations

• Staleness banner is scoped to the remote default base. "Baseline behind GitHub" answers "is origin/<default> ahead of what you're comparing against." If a reviewer picks a different base branch via the base picker, no staleness warning is shown for that base — supporting arbitrary-base upstream staleness is a separate feature, not built here. The common cases are covered: the default base, and a bare local default name (main) which is canonicalized to its tracking ref both at startup and on every resolveReviewBase call.
• Committed deletion + untracked recreation shows as a plain new file. If a branch commits the deletion of f and the user later recreates f untracked, the since-base dedupe (removeTrackedDeletions) drops the committed deletion and the review shows only the untracked addition — the removal of the base version is hidden. Fixing it would require two same-path diff entries, which the path-keyed UI (dock panel, nav, sections map, viewed state) cannot represent. Accepted: the reviewer still sees the file's full current content.
• Index-only changes are not a separate layer. Since-base diffs the WORKING TREE against the merge-base — "what lands if you git add -A && git commit right now", which is the product promise. A change that exists only in the index (edit → git add → restore the working tree to base content) does not appear, because committing everything now would not include it. Deliberate semantics, not an oversight.
• A filename literally containing -> can misgroup in the sidebar. Porcelain v1 doesn't quote plain spaces, so a rename involving such a name splits at the wrong separator and both sides fall back to the Committed group. Only --porcelain -z fully disambiguates; not worth the parser rewrite for a pathological name. Display-only.

Reference files

• Decision: adr/decisions/005-since-base-github-view-default-20260701-223706.md
• Spec: adr/specs/github-view-three-stack-20260701-222935.md
• Intent: adr/intent-since-base-github-view-20260701-224500.md
• Research: adr/research/SPIKE-github-view-composite-diff-20260701-222935.md, adr/research/synthesis-github-view-20260701-222935.md