name: diff-js-api-changes
description: Check for breaking changes in the public React Native JS API
runs:
  using: composite
  steps:
    - name: Get merge base commit with main
      id: merge_base
      shell: bash
      run: |
        git fetch origin main
        git fetch origin ${{ github.event.pull_request.head.sha }} --depth=100
        BASE=$(git merge-base ${{ github.event.pull_request.head.sha }} origin/main)
        echo "merge_base=$BASE" >> $GITHUB_OUTPUT

    - name: Fetch snapshots from PR head and merge base
      shell: bash
      env:
        SCRATCH_DIR: ${{ runner.temp }}/diff-js-api-changes
      run: |
        mkdir -p $SCRATCH_DIR
        # Fetch from merge base
        git show ${{ steps.merge_base.outputs.merge_base }}:packages/react-native/ReactNativeApi.d.ts > $SCRATCH_DIR/ReactNativeApi-before.d.ts \
          || echo "" > $SCRATCH_DIR/ReactNativeApi-before.d.ts
        # Fetch from PR head
        git show ${{ github.event.pull_request.head.sha }}:packages/react-native/ReactNativeApi.d.ts > $SCRATCH_DIR/ReactNativeApi-after.d.ts \
          || echo "" > $SCRATCH_DIR/ReactNativeApi-after.d.ts

    - name: Run breaking change detection
      shell: bash
      env:
        SCRATCH_DIR: ${{ runner.temp }}/diff-js-api-changes
      run: |
        node ./scripts/js-api/diff-api-snapshot \
        $SCRATCH_DIR/ReactNativeApi-before.d.ts \
        $SCRATCH_DIR/ReactNativeApi-after.d.ts \
        > $SCRATCH_DIR/output.json