.github/actions/has-engine-changes/action.yml

name: 'Has Engine Changes'
description: 'Checks if there are any engine changes in the current branch'
outputs:
  changed:
    description: "Returns 'true' if there are engine changes, 'false' otherwise"
    value: ${{ steps.check.outputs.changed }}
runs:
  using: "composite"
  steps:
    - name: Fetch upstream master (if not flutter/flutter)
      if: github.repository != 'flutter/flutter' && !env.ACT
      shell: bash
      run: |
        if ! git remote get-url upstream >/dev/null 2>&1; then
          git remote add upstream https://github.com/flutter/flutter.git
        fi
        git fetch --no-tags upstream master:refs/remotes/upstream/master

    - name: Check Engine Changes
      id: check
      shell: bash
      env:
        EVENT_NAME: ${{ github.event_name }}
        GITHUB_REPOSITORY: ${{ github.repository }}
        PR_BASE_SHA: ${{ github.event.pull_request.base.sha }}
        MERGE_GROUP_BASE_SHA: ${{ github.event.merge_group.base_sha }}
        PUSH_BEFORE_SHA: ${{ github.event.before }}
      run: |
        EMPTY_SHA="0000000000000000000000000000000000000000"
        if [ "$EVENT_NAME" = "pull_request" ]; then
          if [ "$GITHUB_REPOSITORY" != "flutter/flutter" ] && \
             git show-ref --verify --quiet refs/remotes/upstream/master && \
             git merge-base --is-ancestor "$PR_BASE_SHA" refs/remotes/upstream/master 2>/dev/null; then
            BASE_REF="refs/remotes/upstream/master"
          else
            BASE_REF="$PR_BASE_SHA"
          fi
        elif [ "$EVENT_NAME" = "merge_group" ]; then
          BASE_REF="$MERGE_GROUP_BASE_SHA"
        elif [ "$EVENT_NAME" = "push" ] && [ -n "$PUSH_BEFORE_SHA" ] && [ "$PUSH_BEFORE_SHA" != "$EMPTY_SHA" ]; then
          BASE_REF="$PUSH_BEFORE_SHA"
        else
          if git show-ref --verify --quiet refs/remotes/upstream/master; then
            BASE_REF="upstream/master"
          else
            BASE_REF="origin/master"
          fi
        fi

        echo "Comparing against base SHA: $BASE_REF"

        CHANGED_FILES=$(.github/scripts/git_files_changed.sh "$BASE_REF")
        echo "Changed files in this branch:"
        echo "$CHANGED_FILES"

        if [ "$(printf '%s\n' "$CHANGED_FILES" | .github/scripts/did_engine_change.sh)" = "true" ]; then
          echo "Engine files changed."
          echo "changed=true" >> "$GITHUB_OUTPUT"
        else
          echo "No engine files changed."
          echo "changed=false" >> "$GITHUB_OUTPUT"
        fi