name: diff-js-api-changes
description: Check for breaking changes in the public React Native JS API
runs:
  using: composite
  steps:
    - name: Fetch PR and main, compute merge base
      id: merge_base
      shell: bash
      env:
        PR_SHA: ${{ github.event.pull_request.head.sha }}
      run: |
        git fetch origin main
        git fetch origin "$PR_SHA" --depth=500
        echo "merge_base=$(git merge-base "$PR_SHA" origin/main)" >> $GITHUB_OUTPUT

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