ci: Enforce conventional commit format for PR titles (#3666)

* ci: Enforce Sentry commit message convention on PR titles

Adds a workflow that fails when a PR title does not match the
`<type>(<scope>)?: <Subject>` convention from
https://develop.sentry.dev/engineering-practices/commit-messages/.
Re-validates on title edits. Can be bypassed with an `ignore-title`
label if ever needed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* ci: Align PR title regex with release.yml categories

- Add `impr`, `enh`, `deps`, `refactor`, `tests` (plural) to match the
  types categorized by `.github/release.yml`.
- Allow breaking-change `!` suffix (e.g. `feat!: ...`) consistent with
  the Breaking Changes pattern in release.yml.
- Drop `license` — not recognized by release.yml and rare enough to
  lose.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* docs(agents): Add minimal PR description guidance

Document that PR descriptions stay minimal by default and avoid test-plan
checklists unless explicitly requested.

This keeps /create-pr output concise and aligned with repository
expectations.

Co-Authored-By: Codex 5.3 <noreply@openai.com>
Made-with: Cursor

* Revise PR title format for capitalization requirement

Updated PR title format to require capitalization.

* ci: Inline PR title validation workflow

Run title validation directly in github-script, remove the checked-out
local JS helper, and validate associated PRs for merge_group events.

Also relax subject-case enforcement so updater PR titles like
`chore(deps): update ...` continue to pass and map to Dependencies.

Co-Authored-By: Codex 5.3 <noreply@openai.com>
Made-with: Cursor

* ci: Run PR title check on sync updates

Include the pull_request synchronize event so the PR title workflow reruns
when new commits are pushed to an existing pull request.

Co-Authored-By: Codex 5.3 <noreply@openai.com>
Made-with: Cursor

* ci: Remove ignore-label bypass from title check

Drop the ignore-title label escape hatch from the PR title workflow so
all non-draft, non-merged PRs are consistently validated.

Co-Authored-By: Codex 5.3 <noreply@openai.com>
Made-with: Cursor

* ci: Rename PR title check job label

Update the workflow job name to `Check Conventional PR Title` so the
GitHub checks list is more explicit.

Co-Authored-By: Codex 5.3 <noreply@openai.com>
Made-with: Cursor

* ci: Remove merge_group from PR title workflow

Drop merge_group triggering and simplify the script to validate only
pull_request payloads.

This removes an unnecessary code path and avoids misleading merge_group
failure messages.

Co-Authored-By: Codex 5.3 <noreply@openai.com>
Made-with: Cursor

* ci: Enforce capitalized PR titles for humans

Require capitalized PR title subjects for human-authored pull requests
while allowing lowercase starts for automated bot PRs.

Update AGENTS guidance to match the bot exception and keep documented
conventions aligned with CI behavior.

Co-Authored-By: Codex 5.3 <noreply@openai.com>
Made-with: Cursor

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Codex 5.3 <noreply@openai.com>

Author: 3 people

.github/workflows/pr-title.yml

@@ -0,0 +1,85 @@
+name: 'PR Title'
+on:
+  pull_request:
+    types:
+      [
+        opened,
+        synchronize,
+        edited,
+        reopened,
+        ready_for_review,
+        labeled,
+        unlabeled,
+      ]
+permissions:
+  contents: read
+  pull-requests: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  check:
+    name: Check Conventional PR Title
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
+        with:
+          script: |
+            const TITLE_RE = /^(ci|build|docs|feat|fix|perf|ref|refactor|impr|enh|deps|style|chore|tests?|meta)(\([^)]+\))?!?: [A-Z`'"].*[^,.]$/;
+            const AUTOMATED_TITLE_RE = /^(ci|build|docs|feat|fix|perf|ref|refactor|impr|enh|deps|style|chore|tests?|meta)(\([^)]+\))?!?: [A-Za-z`'"].*[^,.]$/;
+
+            function isRevert(title) {
+              return /^Revert ".*"$/.test(title || '');
+            }
+
+            function isAutomatedPr(pr) {
+              const login = (pr.user?.login || '').toLowerCase();
+              return (
+                pr.user?.type === 'Bot' ||
+                login === 'github-actions' ||
+                login === 'github-actions[bot]' ||
+                login === 'dependabot[bot]' ||
+                login === 'renovate' ||
+                login === 'renovate[bot]'
+              );
+            }
+
+            function validateTitle(pr) {
+              if (pr.merged || pr.draft) {
+                return null;
+              }
+
+              const titleRe = isAutomatedPr(pr) ? AUTOMATED_TITLE_RE : TITLE_RE;
+              if (titleRe.test(pr.title || '') || isRevert(pr.title)) {
+                return null;
+              }
+
+              return `#${pr.number}: "${pr.title}"`;
+            }
+
+            const pr = context.payload.pull_request;
+            if (!pr) {
+              core.setFailed('Missing pull_request payload.');
+              return;
+            }
+
+            const failures = [validateTitle(pr)].filter(Boolean);
+            if (failures.length > 0) {
+              core.setFailed(
+                `PR title does not match Sentry conventions:\n${failures.join('\n')}`
+              );
+              core.info(
+                'Please follow the Sentry commit message conventions: https://develop.sentry.dev/engineering-practices/commit-messages/'
+              );
+              core.info('Format: <type>(<scope>): <subject>');
+              core.info(
+                'For human-authored PRs, subject must be capitalized and must not end with a period.'
+              );
+              core.info(
+                'Automated bot PRs (dependabot/github-actions/renovate) may start with lowercase.'
+              );
+            } else {
+              core.info('Validated PR title.');
+            }

AGENTS.md

@@ -68,7 +68,7 @@ Run from within the package directory (e.g., `cd packages/dart/`):
 
 ## Pull Requests
 
-- **Title** — same format as commit subject (Conventional Commits): `type(scope): description`
+- **Title** — same format as commit subject where the beginning of subject must be capitalized for human-authored PRs (Conventional Commits): `type(scope): Capitalized description` (automated bot PRs may start lowercase)
 - **Branch naming** — `<type>/<short-description>` (e.g., `feat/session-replay-privacy`, `fix/memory-leak-scope`)
 - **PR template** — `.github/pull_request_template.md` includes: description, motivation, how tested, checklist
 - **Reviewers** — assigned via `CODEOWNERS` (`.github/CODEOWNERS`); one maintainer approval is sufficient