_code-changes.yml

name: Reusable Code Changes

# Tells pr-tests.yml and pr-coverage.yml whether a pull request needs the Python unit tests. Each still runs its summary
# job when it doesn't, so the summary checks that branch protection requires always report.

on:
  workflow_call:
    outputs:
      code:
        description: "'true' when the pull request changes a file the Python unit tests depend on"
        value: ${{ jobs.changes.outputs.code }}

permissions: {}

jobs:
  changes:
    name: Detect code changes
    runs-on: ubuntu-latest
    permissions:
      pull-requests: read
    outputs:
      code: ${{ steps.files.outputs.code }}
    steps:
      - name: Check the changed files
        id: files
        uses: actions/github-script@v9
        with:
          script: |
            // `make test` collects neither the Rust crate nor integration_tests/: relay-plugin.yml and
            // integration-tests.yml run them.
            const needsNoTests = [
              /\.md$/,
              /^\.github\//,
              /^crates\//,
              /^Cargo\.(toml|lock)$/,
              /^rust-toolchain\.toml$/,
              /^\.cargo\//,
              /^integration_tests\//,
            ];
            const needsTests = (name) => !needsNoTests.some((pattern) => pattern.test(name));

            const files = await github.paginate(github.rest.pulls.listFiles, {
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: context.payload.pull_request.number,
              per_page: 100,
            });
            // The API lists at most 3,000 files, so a pull request that reaches the limit counts as a code change.
            // A file moved out of a tested path counts as well.
            const code =
              files.length >= 3000 ||
              files.some((file) => needsTests(file.filename) || (file.previous_filename && needsTests(file.previous_filename)));
            core.info(`${files.length} changed files; the Python unit tests ${code ? "run" : "are skipped"}.`);
            core.setOutput("code", String(code));