From 5ac5dc4c95a54eb860caef6a66a2f2f81243153d Mon Sep 17 00:00:00 2001
From: Powei Feng <powei@google.com>
Date: Tue, 3 Mar 2026 09:24:00 -0800
Subject: [PATCH] ci: fetch PR ref explicitly to extract commit message for
 forks (#9756)

---
 .github/actions/get-commit-msg/action.yml | 32 ++++++++++++-----------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/.github/actions/get-commit-msg/action.yml b/.github/actions/get-commit-msg/action.yml
index 88e20ec84d..bc5e1bda32 100644
--- a/.github/actions/get-commit-msg/action.yml
+++ b/.github/actions/get-commit-msg/action.yml
@@ -27,17 +27,24 @@ runs:
         echo "$HASH" > /tmp/commit_hash.txt
     - name: Find commit message (PR)
       shell: bash
-      id: checkout_code
       if: github.event_name == 'pull_request'
       run: |
-        BEFORE_HASH=$(git rev-parse HEAD)
-        echo "hash=$BEFORE_HASH" >> "$GITHUB_OUTPUT"
-        # Next we will checkout the actual head (not the merge commits) of the PR
-        AFTER_HASH="${{ github.event.pull_request.head.sha }}"
-        git checkout $AFTER_HASH
-        COMMIT_MESSAGE=$(git log -1 --no-merges)
-        echo "$COMMIT_MESSAGE" > /tmp/commit_msg.txt
-        echo "$AFTER_HASH" > /tmp/commit_hash.txt
+        PR_NUMBER="${{ github.event.pull_request.number }}"
+        # Fetch the head of the PR explicitly to handle forks. Depth 50 ensures we can traverse past recent merge commits.
+        git fetch --depth=50 origin "pull/$PR_NUMBER/head:pr-head"
+
+        COMMIT_HASH=$(git log -1 --no-merges pr-head --format=%H)
+        AUTHOR_NAME=$(git log -1 --no-merges pr-head --format=%an)
+        AUTHOR_EMAIL=$(git log -1 --no-merges pr-head --format=%ae)
+        TSTAMP=$(git log -1 --no-merges pr-head --format=%aI)
+        COMMIT_MESSAGE=$(git log -1 --no-merges pr-head --format=%B)
+
+        echo "commit $COMMIT_HASH" > /tmp/commit_msg.txt
+        echo "Author: ${AUTHOR_NAME}<${AUTHOR_EMAIL}>" >> /tmp/commit_msg.txt
+        echo "Date: ${TSTAMP}" >> /tmp/commit_msg.txt
+        echo "" >> /tmp/commit_msg.txt
+        echo "$COMMIT_MESSAGE" >> /tmp/commit_msg.txt
+        echo "$COMMIT_HASH" > /tmp/commit_hash.txt
     - shell: bash
       id: action_output
       run: |
@@ -47,9 +54,4 @@ runs:
         cat /tmp/commit_msg.txt >> "$GITHUB_OUTPUT"
         echo "$DELIMITER" >> "$GITHUB_OUTPUT"
         # Get the commit hash
-        echo "hash=$(cat /tmp/commit_hash.txt)" >> "$GITHUB_OUTPUT"
-    - name: Cleanup Find commit message (PR)
-      shell: bash
-      if: github.event_name == 'pull_request'
-      run: |
-        git checkout ${{ steps.checkout_code.outputs.hash }}
\ No newline at end of file
+        echo "hash=$(cat /tmp/commit_hash.txt)" >> "$GITHUB_OUTPUT"
\ No newline at end of file