Fix PR lookup in pr-review-responder workflow for fork PRs (#2323)

## Summary - Fixed the pr-review-responder workflow failing to find PRs from forks - Added a fallback that searches for open PRs using `pulls.list` API with the head repository owner and branch name when `workflow_run.pull_requests` array is empty ## Test plan - Create a PR from a fork with the `cc:request` label - Verify the workflow can now correctly find and process the PR #skip-bugbot Generated with [Claude Code](https://claude.com/claude-code)  --- ## Summary by cubic Fixes PR lookup in the pr-review-responder workflow for forked PRs. Adds a fallback search by head owner and branch when workflow_run.pull_requests is empty, so fork PRs are processed correctly. - **Bug Fixes** - Handle empty workflow_run.pull_requests for cross-repo PRs. - Use pulls.list with head "<owner>:<branch>" to find the PR number. - Exit early (should_continue=false) if no matching open PR is found. <sup>Written for commit 70e3c1399b438d5fe768aa9171ec2bf683bc38ff. Summary will update on new commits.</sup>  --------- Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Fix PR lookup in pr-review-responder workflow for fork PRs (#2323)
da6abfe0 · Will Chen · GitHub · 20938765 · da6abfe0
--- a/.github/workflows/pr-review-responder.yml
+++ b/.github/workflows/pr-review-responder.yml
@@ -30,13 +30,34 @@ jobs:
            const run = context.payload.workflow_run;

            // Get PR associated with this workflow run
-            if (!run.pull_requests || run.pull_requests.length === 0) {
-              console.log('No pull requests associated with this workflow run');
+            // Note: run.pull_requests can be empty for cross-repo PRs (forks)
+            // So we also search by head SHA as a fallback
+            let prNumber;
+
+            if (run.pull_requests && run.pull_requests.length > 0) {
+              prNumber = run.pull_requests[0].number;
+            } else {
+              // Search for PRs with matching head branch
+              // Note: head_repository can be null if the fork was deleted
+              if (!run.head_repository) {
+                console.log('Head repository not available');
                core.setOutput('should_continue', 'false');
                return;
              }
+              const { data: prs } = await github.rest.pulls.list({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                state: 'open',
+                head: `${run.head_repository.owner.login}:${run.head_branch}`
+              });

-            const prNumber = run.pull_requests[0].number;
+              if (prs.length === 0) {
+                console.log('No pull requests found for this workflow run');
+                core.setOutput('should_continue', 'false');
+                return;
+              }
+              prNumber = prs[0].number;
+            }

            // Fetch full PR details to get labels
            const { data: pr } = await github.rest.pulls.get({