# API Conformance Tests
# This workflow ensures that API changes maintain backward compatibility and don't break existing integrations
# It runs schema validation and OpenAPI diff checks to catch breaking changes early

name: API Conformance Tests

run-name: Run the API Conformance test suite on the changes.

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]
    types: [opened, synchronize, reopened, edited]
    paths:
      - 'docs/static/llama-stack-spec.yaml'
      - 'docs/static/llama-stack-spec.html'
      - '.github/workflows/conformance.yml' # This workflow itself

concurrency:
  group: ${{ github.workflow }}-${{ github.ref == 'refs/heads/main' && github.run_id || github.ref }}
  # Cancel in-progress runs when new commits are pushed to avoid wasting CI resources
  cancel-in-progress: true

jobs:
  # Job to check if API schema changes maintain backward compatibility
  check-schema-compatibility:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout PR Code
        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
        with:
          fetch-depth: 0

      # Check if we should skip conformance testing due to breaking changes
      - name: Check if conformance test should be skipped
        id: skip-check
        run: |
          PR_TITLE="${{ github.event.pull_request.title }}"

          # Skip if title contains "!:" indicating breaking change (like "feat!:")
          if [[ "$PR_TITLE" == *"!:"* ]]; then
            echo "skip=true" >> $GITHUB_OUTPUT
            exit 0
          fi

          # Get all commits in this PR and check for BREAKING CHANGE footer
          git log --format="%B" ${{ github.event.pull_request.base.sha }}..${{ github.event.pull_request.head.sha }} | \
            grep -q "BREAKING CHANGE:" && echo "skip=true" >> $GITHUB_OUTPUT || echo "skip=false" >> $GITHUB_OUTPUT
        shell: bash
      # Checkout the base branch to compare against (usually main)
      # This allows us to diff the current changes against the previous state
      - name: Checkout Base Branch
        if: steps.skip-check.outputs.skip != 'true'
        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
        with:
          ref: ${{ github.event.pull_request.base.ref }}
          path: 'base'

      # Cache oasdiff to avoid checksum failures and speed up builds
      - name: Cache oasdiff
        if: steps.skip-check.outputs.skip != 'true'
        id: cache-oasdiff
        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830
        with:
          path: ~/oasdiff
          key: oasdiff-${{ runner.os }}

      # Install oasdiff: https://github.com/oasdiff/oasdiff, a tool for detecting breaking changes in OpenAPI specs.
      - name: Install oasdiff
        if: steps.skip-check.outputs.skip != 'true' && steps.cache-oasdiff.outputs.cache-hit != 'true'
        run: |
          curl -fsSL https://raw.githubusercontent.com/oasdiff/oasdiff/main/install.sh | sh
          cp /usr/local/bin/oasdiff ~/oasdiff

      # Setup cached oasdiff
      - name: Setup cached oasdiff
        if: steps.skip-check.outputs.skip != 'true' && steps.cache-oasdiff.outputs.cache-hit == 'true'
        run: |
          sudo cp ~/oasdiff /usr/local/bin/oasdiff
          sudo chmod +x /usr/local/bin/oasdiff

      # Run oasdiff to detect breaking changes in the API specification
      # This step will fail if incompatible changes are detected, preventing breaking changes from being merged
      - name: Run OpenAPI Breaking Change Diff
        if: steps.skip-check.outputs.skip != 'true'
        run: |
          oasdiff breaking --fail-on ERR base/docs/static/llama-stack-spec.yaml docs/static/llama-stack-spec.yaml --match-path '^/v1/'

      # Report when test is skipped
      - name: Report skip reason
        if: steps.skip-check.outputs.skip == 'true'
        run: |
          echo "Conformance test skipped due to breaking change indicator"