Docs Alias Failure Notification workflow (vercel/turbo)

# Docs Alias Failure Notification
#
# Sends a Slack notification when the versioned docs alias assignment fails.

name: Docs Alias Failure Notification

env:
  TURBO_TELEMETRY_MESSAGE_DISABLED: "1"

on:
  workflow_run:
    workflows: ["Release"]
    types:
      - completed

permissions:
  contents: read

jobs:
  notify-failure:
    name: "Notify Slack on Docs Alias Failure"
    runs-on: ubuntu-latest
    if: ${{ github.event.workflow_run.conclusion == 'failure' }}
    steps:
      # Fetch version.txt via the API at the exact commit of the failed run
      # instead of checking out the branch. This avoids checking out a ref by
      # name (the staging branch may already be deleted by the failure cleanup
      # job) and avoids putting any repo content on disk.
      - name: Get version
        id: version
        shell: bash
        env:
          GH_TOKEN: ${{ github.token }}
          HEAD_SHA: ${{ github.event.workflow_run.head_sha }}
        run: |
          if CONTENT=$(gh api -H "Accept: application/vnd.github.raw+json" "repos/${{ github.repository }}/contents/version.txt?ref=${HEAD_SHA}"); then
            IFS= read -r VERSION <<< "$CONTENT"
            if [[ "$VERSION" =~ ^[0-9]+\.[0-9]+\.[0-9]+(-[0-9A-Za-z.]+)?$ ]]; then
              printf 'version=%s\n' "$VERSION" >> "$GITHUB_OUTPUT"
            else
              echo "::warning::version.txt did not contain a valid release version. Reporting unknown version."
              echo "version=unknown" >> "$GITHUB_OUTPUT"
            fi
          else
            echo "::warning::Could not fetch version.txt at ${HEAD_SHA}. Reporting unknown version."
            echo "version=unknown" >> "$GITHUB_OUTPUT"
          fi

      - name: Send failure notification to Slack
        uses: slackapi/slack-github-action@485a9d42d3a73031f12ec201c457e2162c45d02d # v2.0.0
        with:
          webhook: ${{ secrets.DOCS_ALIAS_FAILURE_SLACK_WEBHOOK_URL }}
          webhook-type: incoming-webhook
          payload: |
            {
              "version": ${{ toJSON(steps.version.outputs.version) }}
            }