From c58eded00cce3afe7f4e7bce0de8a67b6cdce32a Mon Sep 17 00:00:00 2001
From: Yakun Xu <xyk@google.com>
Date: Fri, 31 Jul 2026 04:59:16 +0800
Subject: [PATCH] [ci] use head repo looking up pr_number (#13446)

The API github.rest.repos.listPullRequestsAssociatedWithCommit() can
only query commits from the repo owning those commits. Although a fork
PR is pushed to the base repo, the base repo doesn't have the commit
yet. This commit changes the workflow to query pull request from head
repo.
---
 .github/workflows/size-report.yml | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/size-report.yml b/.github/workflows/size-report.yml
index e4deb4532..0c50b62a7 100644
--- a/.github/workflows/size-report.yml
+++ b/.github/workflows/size-report.yml
@@ -65,14 +65,22 @@ jobs:
           let pr_number = context.payload.workflow_run.pull_requests?.[0]?.number
 
           if (!pr_number) {
+            const head_repo = context.payload.workflow_run.head_repository?.full_name;
+            if (!head_repo) {
+              core.setFailed('Head repository not found in workflow run context payload.');
+              return;
+            }
+            const [owner, repo] = head_repo.split('/')
             const { data: prs } = await github.rest.repos.listPullRequestsAssociatedWithCommit({
-              owner: context.repo.owner,
-              repo: context.repo.repo,
+              owner,
+              repo,
               commit_sha: context.payload.workflow_run.head_sha,
             })
-            const open_pr = prs?.find(pr => pr.state === 'open') || prs?.[0]
-            if (open_pr) {
-              pr_number = open_pr.number
+            const base_full_name = `${context.repo.owner}/${context.repo.repo}`
+            const pr = prs?.find(pr => pr.base.repo.full_name === base_full_name && pr.state === 'open') ||
+                       prs?.find(pr => pr.base.repo.full_name === base_full_name);
+            if (pr) {
+              pr_number = pr.number
             }
           }