perf(server): merge separate staged/unstaged numstat calls into single diff HEAD --numstat

[UtkarshUsername]

What Changed

Merged two separate git diff --numstat and git diff --cached --numstat calls into a single git diff HEAD --numstat call. Also simplified the parsing loop from merging staged+unstaged entries into a single flat iteration.

Why

The separate staged/unstaged breakdown was never used individually. Both were immediately summed together per file path into a combined total. git diff HEAD --numstat produces the same combined total directly, eliminating one git subprocess per status refresh.

Benchmark (20 runs each):

• Old (2 calls): ~790ms
• New (1 call): ~311ms
• Saving: ~479ms per refresh

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

Medium Risk
Behavior change to how line stats are computed for statusDetails (net vs HEAD, not summed staged+unstaged); low blast radius but UI/commit flows that show those numbers may differ for mixed-index files.

Overview
readStatusDetailsLocal in GitVcsDriverCore now loads working-tree line stats with a single git diff HEAD --numstat instead of parallel git diff --numstat and git diff --cached --numstat, cutting one Git subprocess per status refresh.

Per-file insertions/deletions are taken directly from that output (net vs HEAD), which fixes double-counting when the same path has both staged and unstaged edits; parsing no longer merges two numstat maps by summing.

When git diff HEAD fails on a repo with no commits (unborn HEAD), the driver detects that stderr via isUnbornHeadStderr and falls back to the previous two-diff merge; other numstat failures surface as GitCommandError.

Integration tests cover combined staged/unstaged edits on one file and staged counts on unborn HEAD.

^{Reviewed by Cursor Bugbot for commit 2b56da6. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Merge separate staged/unstaged git diff --numstat calls into a single git diff HEAD --numstat in statusDetails

• Replaces two separate git diff --numstat (unstaged) and git diff --cached --numstat (staged) calls with a single git diff HEAD --numstat, so per-file insertion/deletion counts reflect combined staged and unstaged changes relative to HEAD.
• Adds fallback handling for unborn HEAD: when git diff HEAD --numstat exits non-zero with an unborn-HEAD stderr, both git diff --numstat and git diff --cached --numstat are run and their results merged per file.
• Non-unborn-HEAD failures now propagate as a GitCommandError instead of being silently ignored.
• Behavioral Change: file stats now represent combined diff from HEAD rather than independent staged and unstaged counts, which changes reported insertions/deletions for files modified in both index and working tree.

^{Macroscope summarized 2b56da6.}

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[macroscopeapp]

Effect service conventions review: one finding — a backend behavior change in GitVcsDriverCore.statusDetails lands without focused test coverage.

^{Posted via Macroscope — Effect Service Conventions}

[macroscopeapp]

This changes statusDetails backend behavior (staged+unstaged line counts are now a single diff HEAD instead of summed diff + diff --cached), so it should come with focused tests in GitVcsDriverCore.test.ts rather than none. Two cases worth covering:

• a file that is staged and then modified again in the working tree, asserting the counts are no longer double-counted;
• a repository with no commits yet (unborn HEAD): git diff HEAD --numstat exits non-zero there, and because runGitStdout is called without allowNonZeroExit, statusDetails would now fail where the previous diff / diff --cached pair succeeded. If that case is reachable, handle it (e.g. allowNonZeroExit plus an empty-stat fallback, or diff against the empty tree) and pin it with a test.

^{Posted via Macroscope — Effect Service Conventions}

[macroscopeapp]

Approvability

Verdict: Approved 2b56da6

Performance optimization that merges two git diff calls into one, with appropriate fallback handling for edge cases (unborn HEAD) and new test coverage addressing both scenarios raised in review feedback.

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

[macroscopeapp]

Follow-up on the numstat consolidation: the new unborn-HEAD fallback now hides genuine git diff failures, and the changed counting behavior is still untested.

^{Posted via Macroscope — Effect Service Conventions}

[cursor]

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

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit 66de31a. Configure here.}

Dismissing prior approval to re-evaluate 812b47c

[macroscopeapp]

One residual finding on the new unborn-HEAD fallback in readStatusDetailsLocal. The classification via isUnbornHeadStderr addresses the earlier concern; the remaining issue is the suppressed failure channel in the fallback commands.

^{Posted via Macroscope — Effect Service Conventions}