fix(code-review): show PR comment counts on files

[MattPua]

Problem

PR file headers do not show which files have review comments or how many comments they contain, making it hard to look for comments when looking at PR files

Changes

• Show comment counts in PR file headers when collapsed or expanded
• Place comment counts before line change stats
• Count all comments and replies for each file

How did you test this?

• pnpm --filter @posthog/ui exec vitest run src/features/code-review/components/ReviewRows.test.tsx src/features/code-review/reviewShellParts.test.tsx src/features/code-review/prCommentThreads.test.ts
• pnpm --filter @posthog/ui typecheck
• Commit hook repository-wide pnpm typecheck

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

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Created with PostHog Code

[trunk-io]

😎 Merged successfully - details.

[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit a6cce55.}

[github-actions]

Focused, additive UI fix that threads a new headerMetadata ReactNode prop through file-diff headers to display per-file PR comment counts. The logic extracted from usePrDetails.ts into the new prCommentThreads.ts is a pure refactor (same behavior), and the new badge component and count helper are both covered by new unit tests.

[greptile-apps]

_{Reviews (1): Last reviewed commit: "fix(code-review): show PR comment counts..." | Re-trigger Greptile}

[stamphog]

Retaining stamphog approval — delta since last review classified as trivial_paths.

[MattPua]

Note

🤖 Automated follow-up by PostHog Code, not written by a human

Ran the xp-reviewer perspective against this PR.

Result

✅ Approved with no blocking correctness, scope, duplication, or maintainability findings.

Follow-up applied

• Addressed the non-blocking test-coverage nit in f0dc20381
• Added PatchedFileDiff coverage proving comment metadata reaches regular, binary, and unavailable file headers
• Verified metadata remains before line-change stats in every path

Validation

• 15 focused tests pass
• @posthog/ui typecheck passes
• Repository-wide commit-hook typecheck passes

New commits pushed (delta classified non_trivial_delta) — stamphog approval dismissed; re-review running automatically.

[github-actions]

Purely additive UI fix: extracts a utility, threads an optional prop, adds a badge component, and covers everything with new unit tests. Both bot comments are outdated — the renamed-file concern is already handled in the code, and the incomplete-callers concern is a graceful degradation, not a bug.

New commits pushed (delta classified non_trivial_delta) — stamphog approval dismissed; re-review running automatically.

[github-actions]

No showstoppers. Additive UI fix that threads an optional comment-count prop through file diff headers, with correct renamed-file handling and good test coverage.

New commits pushed (delta classified non_trivial_delta) — stamphog approval dismissed; re-review running automatically.

[github-actions]

Additive UI fix that threads an optional comment-count badge through file diff headers, with correct renamed-file handling and solid test coverage. All inline review concerns were addressed. No showstoppers.

New commits pushed (delta classified non_trivial_delta) — stamphog approval dismissed; re-review running automatically.

[github-actions]

Purely additive UI fix that threads an optional comment-count badge through file diff headers. Logic is correct, uses quill primitives as required, both greptile concerns (renamed files, direct callers) are addressed in the current diff, and new tests cover all three header variants.