name: Merge Conflicts

# Reject unresolved Git merge-conflict markers committed into tracked files.
#
# This lives in its own workflow ON PURPOSE: ci.yml sets
# `on.pull_request.paths-ignore: ['**/*.md', ...]`, so a Markdown/CHANGELOG-only
# PR skips that workflow entirely. The conflict markers this guard exists to
# catch landed in CHANGELOG.md, so the check must run with no `paths-ignore`.
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

concurrency:
  group: merge-conflicts-${{ github.event.pull_request.number || github.ref }}
  cancel-in-progress: true

permissions:
  contents: read

jobs:
  merge-conflicts:
    runs-on: ubuntu-latest
    timeout-minutes: 5
    steps:
      - uses: actions/checkout@v7
      - name: Reject unresolved merge-conflict markers
        run: |
          if git grep -nI -E '^(<{7}|>{7}|\|{7})( |$)' -- .; then
            echo "::error::Unresolved Git merge-conflict markers found in tracked files (see matches above)."
            exit 1
          fi
          echo "No merge-conflict markers found."