name: runnability

# Probes every course directory and fails if any RUNNER is broken.
#
# Deliberately NOT a diff against a committed baseline. A runner's status is a
# property of the machine, not of the commit: MATLAB, Unity and the .NET SDK
# are absent here and present locally, so `runnable` on a laptop and `blocked`
# on ubuntu-latest is correct rather than drift. Diffing the two would make
# this workflow red by construction, which is the one outcome the whole
# exercise is meant to avoid.
#
# What IS a defect, and what this catches: a run.sh that crashes, hangs, or
# reports an unknown kind. Those are `error`, and any `error` fails the job.
on:
  push:
    branches: [main]
  pull_request:
  workflow_dispatch:

jobs:
  runnability:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 1

      - name: Probe every course directory
        run: ./run.sh status

      - name: Fail on any broken runner
        run: |
          set -euo pipefail
          if grep -qP '\terror\t' gates/runnability-ci.tsv; then
            echo "::error::a course run.sh failed to probe"
            grep -P '\terror\t' gates/runnability-ci.tsv
            exit 1
          fi
          echo "all runners probed cleanly"
          cut -f2 gates/runnability-ci.tsv | sort | uniq -c