name: Markdown Links

on:
  pull_request:
    branches: [main, develop]
    paths:
      - "**/*.md"
      - "scripts/check-markdown-links.mjs"
      - ".github/workflows/markdown-links.yml"
  push:
    branches: [main, develop]
    paths:
      - "**/*.md"
      - "scripts/check-markdown-links.mjs"
      - ".github/workflows/markdown-links.yml"
  workflow_dispatch:

# CI fan-out fix: the PR-scoped concurrency from #14069 fell back to
# github.run_id on push, so every develop push got a unique group and
# nothing ever superseded. A 37-merge wave queued thousands of push runs
# and starved the self-hosted fleet. Fall back to github.ref (all develop
# pushes share a group) and cancel superseded runs on push too. PR behavior
# is unchanged (pull_request.number still wins the key); merge_group and
# schedule events are not in the cancel set, so the merge queue and nightly
# runs always complete.
concurrency:
  group: markdown-links-${{ github.event.pull_request.number || github.ref }}
  cancel-in-progress: ${{ github.event_name == 'pull_request' || github.event_name == 'push' }}

permissions:
  contents: read

jobs:
  relative-links:
    name: Relative Markdown Links
    runs-on: ${{ fromJSON(vars.HETZNER_FLEET_ONLINE == 'false' && '["ubuntu-24.04"]' || '["self-hosted","hetzner-robot"]') }}
    timeout-minutes: 5
    steps:
      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5
        with:
          submodules: false

      - name: Setup Node.js
        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e
        with:
          node-version: "24.15.0"

      - name: Check relative Markdown links
        run: node scripts/check-markdown-links.mjs