.github/workflows/pr-branch-check.yml

# Copyright (C) 2025 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# When creating stacked PRs, ensure that PRs are based on main (or another
# branch) before submitting. This avoid to accidentally merge PR2 onto PR1,
# if both PR1 and PR2 are opened, which is very confusing when dealing with
# stacked changes.

name: Prevent accidental merge PRs into dev branches
on:
  pull_request:
    types: [opened, synchronize, reopened, edited]
    branches:
      - dev/**/*

jobs:
  pr-branch-check:
    if: startsWith(github.base_ref, 'dev/')
    # Deliberately run on GitHub's ubuntu-latest pool as it's faster for small
    # job like this.
    runs-on: ubuntu-latest
    steps:
      - name: Prevent accidental merge PRs into dev branches
        shell: bash
        run: |
          echo "❌ You are trying to merge the a PR ${{ github.ref }} on top of another one (${{ github.base_ref }})."
          echo "When working with stacked changes you need to first land the upstream PR, then click on the button that suggests to set main as merge base."
          exit 1