name: Lint workflows

# Durable guard against CI-workflow bugs — most importantly the recurring
# "bash-only syntax under the default `sh`/dash shell" footgun that broke
# resolve-versions (ed49b8d) and promote-base-latest (b7197e8 → run 418).
# actionlint runs shellcheck against each `run:` step using its *effective*
# shell, so `set -o pipefail` under dash is flagged as SC3040 before any
# expensive build runs. This is cheap (~10s) and independent of the build
# pipeline, so it fires on every push/PR — not just on release tags, which
# is where the build workflow (docker-publish.yml) is otherwise only
# triggered.
on:
  push:
  pull_request:
  workflow_dispatch:

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

defaults:
  run:
    shell: bash

jobs:
  actionlint:
    runs-on: ubuntu-latest
    container:
      image: catthehacker/ubuntu:act-latest
    steps:
      - uses: actions/checkout@v4

      - name: Install shellcheck
        run: |
          apt-get update
          apt-get install -y --no-install-recommends shellcheck python3-yaml

      - name: Gitea shell guard (catches the actionlint blind spot)
        # actionlint models GitHub Actions, where the default run shell is
        # bash, so it does NOT flag bash syntax in a step that merely OMITS
        # `shell:` — which is exactly how ed49b8d and b7197e8 manifested on
        # Gitea (default sh/dash). This guard enforces that every run: step
        # resolves to bash under Gitea's real defaults. Run it BEFORE
        # actionlint so the more precise diagnostic surfaces first.
        run: bash scripts/check-workflow-shell.sh .gitea/workflows

      - name: Install actionlint (pinned)
        env:
          ACTIONLINT_VERSION: 1.7.7
        run: |
          curl -fsSL \
            "https://github.com/rhysd/actionlint/releases/download/v${ACTIONLINT_VERSION}/actionlint_${ACTIONLINT_VERSION}_linux_amd64.tar.gz" \
            | tar -xz -C /usr/local/bin actionlint
          actionlint --version

      - name: Run actionlint
        # SHELLCHECK_OPTS excludes pure-style codes (quoting/style opinions)
        # so the guard stays focused on correctness bugs — crucially the
        # SC3xxx "not POSIX / wrong shell" family that catches the pipefail
        # footgun. Do NOT exclude SC3040 (set -o pipefail under sh) or any
        # other SC3xxx code.
        env:
          SHELLCHECK_OPTS: "-e SC2086 -e SC2016 -e SC2129 -e SC2001 -e SC2312"
        run: actionlint -color