Missing concurrency group on PR workflow

Rule ID	missing_concurrency
Category	reliability
Severity	medium

PR-triggered workflow has no concurrency group. Multiple pushes to the same PR will queue redundant runs instead of cancelling the previous one.

Detection

static_analysis — Checks field presence or value in the workflow YAML.

Examples

Non-compliant:

on:
  pull_request:
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - run: npm test

Compliant:

on:
  pull_request:
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - run: npm test

Fix: Add a top-level concurrency block with a group key that includes github.ref and set cancel-in-progress: true to cancel superseded runs automatically.