Detect file renames in review diffs

[jakeleventhal]

Verification

1. File rename with no changes

Git detects one rename and the viewer renders a single exact-original.ts → exact-renamed.ts entry with -0 +0 and no content hunk.

2. File rename with minimal changes

Git detects an 84% similar rename, so the viewer keeps one minimal-original.ts → minimal-renamed.ts entry and renders the -1 +1 content diff.

3. File rename with too many changes

The files are below Git's rename-similarity threshold, so the viewer correctly renders replaced-new.ts as an addition and replaced-original.ts as a deletion.

Summary

• enable Git rename detection for working-tree and branch review diffs
• include untracked rename destinations through an isolated temporary index without modifying the user's real index
• preserve content hunks when a renamed file also has minor edits

Root cause

Working-tree previews generated tracked and untracked patches separately. A normal filesystem rename therefore appeared as an unrelated deletion and addition because Git never saw both paths in the same comparison.

Impact

The diff viewer now renders qualifying file moves as one renamed file while still showing any content changes. Branch comparisons use the same explicit Git rename detection.

Validation

• pnpm exec vp test apps/server/src/vcs/GitVcsDriverCore.test.ts (27 tests)
• pnpm exec vp check
• pnpm exec vp run typecheck
• git diff --check

Note

Detect file renames in working-tree and branch-range review diffs

• Replaces the previous approach of per-file --no-index diffs for untracked files with a single unified diff built via a temporary Git index in GitVcsDriverCore.ts.
• Untracked files are staged as intent-to-add in the temp index, and staged deletions are enumerated so the final diff reflects renames, sparse-checkout entries, and deletion context in one pass.
• Adds --find-renames to both the working-tree and branch-range diff invocations.
• Falls back to readTrackedWorkingTreeReviewDiff (tracked changes only, no untracked files) if the temp-index approach fails with a GitCommandError.
• Behavioral Change: working-tree diffs now include untracked files and report truncation if any intermediate listing or diff is truncated; branch-range diffs now surface renames.

^{Macroscope summarized e226410.}

---

Note

Medium Risk
Changes core Git diff preview behavior for dirty worktrees (new subprocess/index workflow) with fallbacks, but mistakes could misrepresent staged/untracked or rename state in the review UI.

Overview
Working-tree review previews no longer merge a tracked git diff HEAD with per-file git diff --no-index for untracked paths. They now build one patch via readWorkingTreeReviewDiff: copy the real index into a temp GIT_INDEX_FILE, stage untracked paths with git add --intent-to-add, run a single git diff --find-renames against HEAD (or an empty tree before the first commit), and tear down the temp index without touching the user’s split/shared index. On failure, readTrackedWorkingTreeReviewDiff still returns tracked changes with rename detection.

Branch-range previews add --find-renames to the existing base…HEAD diff so committed renames show as one entry with content hunks.

Integration tests cover pre-first-commit dirty trees, unstaged/committed renames with edits, sparse-checkout, staged index-only deletions (including truncated deletion lists), nested repos, split-index safety, and several fallback paths when temp-index steps fail.

^{Reviewed by Cursor Bugbot for commit e226410. Bugbot is set up for automated code reviews on this repo. Configure here.}

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[macroscopeapp]

Approvability

Verdict: Needs human review

1 blocking correctness issue found. This PR introduces new rename detection capability in review diffs with substantial implementation complexity (temporary index manipulation, split-index handling, error recovery). The ~200 lines of new implementation logic, runtime behavior changes, and an unresolved High severity finding about silent error handling warrant human review.

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

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Reviewed commit: 0fc42d53cc

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[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: fd2f9f87ba

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[macroscopeapp]

One error-modeling issue found in apps/server/src/vcs/GitVcsDriverCore.ts: the shared-index copyFile failure is not mapped to the service's domain error.

^{Posted via Macroscope — Effect Service Conventions}

[cursor]

Cursor Bugbot has reviewed your changes using high effort and found 1 potential issue.

There are 2 total unresolved issues (including 1 from previous review).

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^{Reviewed by Cursor Bugbot for commit 1535d69. Configure here.}

[macroscopeapp]

Reviewed the new working-tree review-diff helpers against the Effect service conventions. One unmapped platform failure remains in readWorkingTreeReviewDiff.

^{Posted via Macroscope — Effect Service Conventions}

[t3dotgg]

Note

🤖 GPT-5.6 Sol responding on behalf of Theo

Closing this because the branch and screenshots are too far behind the current app.

We are still interested in correct file rename detection. Please open a new, smaller PR based on the latest main, with screenshots of the current UI that show a clear before and after. If the implementation still needs a temporary Git index or extra Git processes, explain why and include its performance impact.

[jakeleventhal]

[!NOTE]
🤖 GPT-5.6 Sol responding on behalf of Theo

Closing this because the branch and screenshots are too far behind the current app.

We are still interested in correct file rename detection. Please open a new, smaller PR based on the latest main, with screenshots of the current UI that show a clear before and after. If the implementation still needs a temporary Git index or extra Git processes, explain why and include its performance impact.

@t3dotgg #8086 voila