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 two-step working-tree diff (tracked HEAD diff + separate git diff --no-index per untracked file) with a single unified diff via the new readWorkingTreeReviewDiff function in GitVcsDriverCore.ts.
• The new function builds a temporary Git index, stages intent-to-add for untracked files, and runs a single patch diff with --find-renames and --minimal against HEAD (or an empty tree when no commits exist yet).
• Adds --find-renames to the branch-range diff so committed renames are also detected.
• Truncation now reflects a single diff operation rather than concatenated outputs.
• Behavioral Change: untracked files, staged index-only deletions, and renames are now included in the working-tree diff; the previous per-file /dev/null diff approach is removed.

^{Macroscope summarized aa8d932.}

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Note

Medium Risk
Core review diff generation changed for all dirty worktrees and branch comparisons; behavior is broader (renames, empty repos) but relies on temp-index Git orchestration where regressions would affect the diff viewer.

Overview
Review working-tree previews no longer merge a tracked git diff HEAD with per-file untracked diff --no-index patches. They now go through readWorkingTreeReviewDiff, which copies the real index into a temporary GIT_INDEX_FILE, stages the tree with git add --intent-to-add -A, and emits one git diff --find-renames against HEAD (or an empty tree before the first commit).

Branch-range previews also pass --find-renames, so committed renames show as renames with content hunks instead of unrelated add/delete pairs.

Integration tests cover pre-first-commit untracked/staged files, unstaged renames with edits, sparse-checkout scope, staged index-only deletions (git rm --cached), and committed renames on the branch diff. Truncation for the dirty worktree now follows that single diff’s byte limit (the old separate untracked/workspace caps are removed).

^{Reviewed by Cursor Bugbot for commit aa8d932. Bugbot is set up for automated code reviews on this repo. Configure here.}

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[macroscopeapp]

Approvability

Verdict: Needs human review

This PR fundamentally changes how working tree review diffs are computed, replacing per-file untracked diff generation with a temporary index-based approach. This is a significant architectural change to core diff logic that affects the review workflow and warrants human review.

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[chatgpt-codex-connector]

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