.github/workflows/daily-grammar-check.yml

name: Daily Grammar Check
on:
  schedule:
    # Run at 4am UTC every day
    - cron: '0 4 * * *'
  workflow_dispatch:

jobs:
  grammar-check:
    if: github.repository == 'rust-lang/reference'
    runs-on: ubuntu-latest
    steps:
    - name: Checkout reference repository
      uses: actions/checkout@v7

    - name: Checkout rust-lang/rust (shallow clone)
      uses: actions/checkout@v7
      with:
        repository: rust-lang/rust
        path: rust
        fetch-depth: 1

    - name: Update rustup
      run: rustup self update

    - name: Install Rust nightly
      run: |
        rustup set profile minimal
        rustup toolchain install nightly -c rustc-dev -c llvm-tools
        rustup default nightly

    - name: Report versions
      run: |
        rustup --version
        rustc -Vv

    - name: Run grammar check
      id: grammar-check
      continue-on-error: true
      run: |
        cargo run --release -p grammar-check -- lex-compare --path rust
        cargo run --release -p grammar-check -- lex-compare --permute Token --tool rustc_parse
        cargo run --release -p grammar-check -- lex-compare --permute three
        cargo run --release -p grammar-check -- lex-compare --tool rustc_parse

    - name: Check for existing open issues
      if: steps.grammar-check.outcome == 'failure'
      id: check-issues
      env:
        GH_TOKEN: ${{ github.token }}
      run: |
        # Check if there's already an open issue with the label 'daily-grammar-check'
        ISSUE_COUNT=$(gh issue list --label "daily-grammar-check" --state open --json number --jq 'length')
        echo "open_issues=$ISSUE_COUNT" >> $GITHUB_OUTPUT

    - name: Create issue on failure
      if: steps.grammar-check.outcome == 'failure' && steps.check-issues.outputs.open_issues == '0'
      env:
        GH_TOKEN: ${{ github.token }}
      run: |
        gh issue create \
          --title "Daily Grammar Check Failed - $(date +%Y-%m-%d)" \
          --label "daily-grammar-check" \
          --body "The daily grammar check failed on $(date +%Y-%m-%d).
        
        **Workflow Run:** ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
        
        **Command:** \`cargo run --release -p grammar-check -- lex-compare --path rust/tests\`
        
        Please investigate the failure and update the reference as needed.
        
        This issue was automatically created by the daily grammar check workflow."