fix(git): disable external diff for review diff previews

[ohbentos]

What Changed

Added --no-color --no-ext-diff --no-textconv to the three git diff invocations in
getReviewDiffPreview (apps/server/src/vcs/GitVcsDriverCore.ts):

• getReviewDiffPreview.dirtyTracked — the Diff panel's Working tree scope
• getReviewDiffPreview.base — the Diff panel's Branch scope (base...HEAD)
• readUntrackedReviewDiffs.diff — untracked files, via --no-index

Flags are inline at each call site, matching the checkpoint diff in GitVcsDriver.ts and the
guidance from #1092 (no shared helper).

Why

When a user has diff.external configured, git diff delegates to that tool and stops emitting a
unified patch, so parsePatchFiles can't read it and the panel falls back to
"Unsupported diff format. Showing raw patch." That's #927.

#927 has already been fixed twice, each time for a different set of call sites, and the review
diff preview was in neither. The flag reached the codebase piecemeal:

Call site	Fixed by
checkpoints.diffCheckpoints	5165b8c (#2586) — incidentally, in a perf PR
prepareCommitContext.stagedPatch	7db0349 (#2553) — the fix that closed #927
readRangeContext.diffPatch	7db0349 (#2553)
getReviewDiffPreview.dirtyTracked	still broken
getReviewDiffPreview.base	still broken
readUntrackedReviewDiffs.diff	still broken

The three remaining ones aren't new code — they landed in b3e8c03 (#2013) on May 29, two weeks
before #2553 — they just weren't in that PR's scope. #2352 and #1092 proposed fixes too, and their
call-site lists didn't include them either. So #927 is closed, and the two scopes users actually
look at in the Diff panel still route through the external tool.

Repro, with any external diff driver (git config --global diff.external difft): open the Diff
panel, switch to Working tree or Branch, and it renders raw tool output instead of a diff. Same
patch fed to parsePatchFiles parses to 0 files with the external driver and 1 file with
--no-ext-diff.

Validation

• vp test run apps/server/src/vcs/GitVcsDriverCore.test.ts — 38 passed
• tsgo --noEmit in apps/server — clean
• Manual repro above, in a scratch repo with diff.external set

No new regression test here, matching #2553.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes

---

Note

Low Risk
Narrow change to git CLI flags on review preview paths; behavior only shifts when users have external diff or textconv configured, and aligns with existing fixed call sites.

Overview
Adds --no-color, --no-ext-diff, and --no-textconv to the three git diff paths that feed the Diff panel review preview in GitVcsDriverCore.ts, matching flags already used on checkpoint, commit, and range diff calls.

Working tree (getReviewDiffPreview.dirtyTracked), branch range (getReviewDiffPreview.base), and untracked (readUntrackedReviewDiffs via --no-index) now always emit a unified patch Git can parse instead of delegating to diff.external, which had left the panel on “Unsupported diff format” for those scopes.

^{Reviewed by Cursor Bugbot for commit 5324f6a. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Disable external diff, textconv, and color in GitVcsDriver review diff previews

Adds --no-ext-diff, --no-textconv, and --no-color flags to all three git diff invocations in GitVcsDriverCore.ts — untracked files, dirty tracked changes, and base comparisons. This ensures raw git output is used instead of any user-configured external diff or textconv drivers.

Behavioral Change: repositories with external diff tools or textconv filters configured will now see different patch output in review diff previews.

^{Macroscope summarized 5324f6a.}

[coderabbitai]

Important

Review skipped

Auto reviews are disabled on this repository. Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 10594932-b6bc-49d1-85df-bf81b3dce668

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

• 🔍 Trigger review

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[macroscopeapp]

Approvability

Verdict: Approved 5324f6a

Adds standard git flags (--no-color, --no-ext-diff, --no-textconv) to diff commands to ensure consistent output regardless of user's local git configuration. This is a defensive fix with clear intent and no behavioral changes beyond making diff generation more robust.

^{You can customize Macroscope's approvability policy. Learn more.}