renderdiff: enable update goldens on commit merge

RDIFF_BRANCH=pf/renderdiff-brach-comp-update

Author: poweifeng

.github/actions/get-commit-msg/action.yml

@@ -0,0 +1,33 @@
+name: 'Get commit message'
+outputs:
+  msg:
+    value: ${{ steps.action_output.outputs.msg }}
+runs:
+  using: "composite"
+  steps:
+    - name: Find commit message (on push)
+      if: github.event_name == 'push'
+      shell: bash
+      run: |
+        echo "${{ github.event.head_commit.message }}" >> /tmp/commit_msg.txt
+    - name: Checkout code
+      shell: bash
+      id: checkout_code
+      if: github.event_name == 'pull_request'
+      run: |
+        echo "hash=$(git rev-parse HEAD)" >> "$GITHUB_OUTPUT"
+        git checkout ${{ github.event.pull_request.head.ref }}
+        COMMIT_MESSAGE=$(git log -1)
+        echo "${COMMIT_MESSAGE}" >> /tmp/commit_msg.txt
+    - shell: bash
+      id: action_output
+      run: |
+        DELIMITER="EOF_FILE_CONTENT_$(date +%s)" # Using timestamp to make it more unique
+        echo "msg<<$DELIMITER" >> "$GITHUB_OUTPUT"
+        cat /tmp/commit_msg.txt >> "$GITHUB_OUTPUT"
+        echo "$DELIMITER" >> "$GITHUB_OUTPUT"
+    - name: Uncheckout code
+      shell: bash
+      if: github.event_name == 'pull_request'
+      run: |
+        git checkout ${{ steps.checkout.outputs.hash }}

.github/workflows/postsubmit.yml

@@ -0,0 +1,32 @@
+# name: 'Post-submit tasks'
+
+# on:
+#   pull_request:
+#     branches:
+#     - main
+#   push:
+#     branches:
+#     - main
+
+# jobs:
+#   update-renderdiff-goldens:
+#     name: update-renderdiff-goldens
+#     runs-on: 'ubuntu-24.04-4core'
+#     steps:
+#       - uses: actions/checkout@v4.1.6
+#         with:
+#           fetch-depth: 0
+#       - uses: ./.github/actions/linux-prereq
+#       - id: get_commit_msg
+#         uses: ./.github/actions/get-commit-msg
+#       - name: Run update script
+#         run: |
+#           GOLDEN_BRANCH=$(echo "${{ steps.get_commit_msg.outputs.msg }}" | python3 test/renderdiff/src/commit_msg.py)
+#           COMMIT_HASH=$(echo "${{ steps.get_commit_msg.outputs.msg }}" | head -n 1 | tr -d 'commit ')
+#           if [[ "${GOLDEN_BRANCH}" != "main" ]]; then
+#               python3 test/renderdiff/src/update_golden.py --branch=${GOLDEN_BRANCH} \
+#                   --merge-to-main --filament-tag=${COMMIT_HASH}
+#               cd filament-assets
+#               git checkout ${GOLDEN_BRANCH}
+#               git log -1
+#           fi