verify.yml

# Python Open Source Challenge — verify
#
# Every file in this repository is broken on purpose, so running all ninety on
# every pull request would always fail and would tell nobody anything.
#
# Instead this runs ONLY the files the pull request actually changed, and
# requires each of them to print "All checks passed!". That is the same command
# the contributor runs on their own machine, so a red check here is always
# reproducible locally in one line.
name: Verify

on:
  pull_request:
  workflow_dispatch:

permissions:
  contents: read

concurrency:
  group: verify-${{ github.ref }}
  cancel-in-progress: true

jobs:
  changed-issues:
    name: the files you changed pass their own checks
    runs-on: ubuntu-latest
    # Contributors' fix PRs are what this check exists for. A maintainer doing
    # repository maintenance touches many issue files at once and those files
    # are SUPPOSED to still fail, so verifying them would always be red and
    # would mean nothing. Outside contributors cannot skip this: only people
    # who already have write access get OWNER/MEMBER/COLLABORATOR here.
    if: >-
      github.event.pull_request.author_association != 'OWNER' &&
      github.event.pull_request.author_association != 'MEMBER' &&
      github.event.pull_request.author_association != 'COLLABORATOR'
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - uses: actions/setup-python@v5
        with:
          python-version: "3.11"

      - name: Work out which issue files changed
        id: changed
        run: |
          base="${{ github.event.pull_request.base.sha }}"
          head="${{ github.event.pull_request.head.sha }}"
          if [ -z "$base" ]; then
            echo "Not a pull request — nothing to compare against."
            echo "files=" >> "$GITHUB_OUTPUT"
            exit 0
          fi
          files=$(git diff --name-only --diff-filter=ACMR "$base" "$head" \
                  -- 'python-open-source-challenge/*.py' | tr '\n' ' ')
          echo "files=$files" >> "$GITHUB_OUTPUT"
          if [ -z "$files" ]; then
            echo "No issue files changed in this pull request."
          else
            echo "Will verify: $files"
          fi

      - name: Run each changed file
        if: steps.changed.outputs.files != ''
        run: |
          failed=0
          for f in ${{ steps.changed.outputs.files }}; do
            echo "::group::$f"
            if output=$(python3 "$f" 2>&1); then
              if echo "$output" | grep -q "All checks passed!"; then
                echo "$output"
                echo "PASS - $f"
              else
                echo "$output"
                echo "::error file=$f::This file ran without error but never printed 'All checks passed!'."
                echo "Check that check_solution() is still called at the bottom of the file."
                failed=1
              fi
            else
              echo "$output"
              echo "::error file=$f::Not fixed yet — this file still fails its own checks."
              echo "Reproduce it locally with:    python3 $f"
              echo "The failing 'assert' line above names the exact input and the expected result."
              failed=1
            fi
            echo "::endgroup::"
          done
          exit $failed

      - name: Nothing to check
        if: steps.changed.outputs.files == ''
        run: |
          echo "This pull request does not change any file in python-open-source-challenge/."
          echo "That is fine — documentation and workflow changes do not need this check."

  one-issue-per-pr:
    name: one issue per pull request
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      # Keeping pull requests to a single file is what makes eighty of them
      # reviewable in one afternoon. This warns rather than blocks, because a
      # contributor who genuinely claimed two issues is not doing anything wrong.
      - name: Count changed issue files
        run: |
          base="${{ github.event.pull_request.base.sha }}"
          head="${{ github.event.pull_request.head.sha }}"
          count=$(git diff --name-only --diff-filter=ACMR "$base" "$head" \
                  -- 'python-open-source-challenge/*.py' | wc -l | tr -d ' ')
          echo "Issue files changed: $count"
          if [ "$count" -gt 1 ]; then
            echo "::warning::This pull request changes $count issue files."
            echo "Pull requests are easiest to review when they fix one issue each."
            echo "If you claimed more than one issue, consider splitting this up."
          fi