如何让GitHub Actions在PR评论后针对Staging分支运行Cypress测试？

我有一个GitHub Actions工作流，会在Pull Request（PR）收到评论后运行Cypress测试。目前的问题是，测试似乎是针对master分支运行的，我希望测试能针对staging分支执行。请问如何实现PR评论后针对staging分支运行测试？

当前的YAML配置文件如下：

name: Cypress Staging Tests
on:
  issue_comment:
    types: [created]

jobs:
  identify-staging-deploy:
    runs-on: ubuntu-latest
    name: deploy to staging comment on pr
    if: contains(github.event.comment.body, 'Successful Gordon Deploy')
    steps:
      - name: Github API Request
        id: gh_request
        uses: octokit/request-action@v2.0.2
        with:
          route: GET /repos/:repository/pulls/:issue_id
          repository: ${{ github.repository }}
          issue_id: ${{ github.event.issue.number }}
        env:
          GITHUB_TOKEN: github secret
      - name: Get PR information
        id: pr_info
        run: |
          echo "::set-output name=branch::${{ fromJson(steps.gh_request.outputs.data).head.ref }}"
          echo "::set-output name=repo_name::${{ fromJson(steps.gh_request.outputs.data).head.repo.full_name }}"
          echo "::set-output name=pr_title::${{ fromJson(steps.gh_request.outputs.data).title }}"
      - name: Checkout repo
        uses: actions/checkout@v2.3.4
        with:
          token: dispatch token
          repository: ${{ steps.pr_info.outputs.repo_name }}
          ref: ${{ steps.pr_info.outputs.branch }}
  
  run-cypress-tests:
    needs: identify-staging-deploy
    runs-on: ubuntu-latest
    steps:
      - name: Checkout 
        uses: actions/checkout@v2
      - name: Setup Node
        uses: actions/setup-node@v3
        with:
          node-version: 12
      - name: Install dependencies
        run: yarn ci:setup
      - name: Cypress Run 
        id: cypress-results
        uses: cypress-io/github-action@v4 
        with: 
          browser: chrome
          record: true
        env:
          CYPRESS_fileConfig: staging
      - name: Post PR Comment
        if: always()
        run: |
          gh api \
          --method POST \
          -H "Accept: application/vnd.github+json" \
          /repos/${{ github.repository_owner }}/repo_name/issues/${{ github.event.issue.number }}/comments \
          -f body='#### Cypress Tests: ${{ steps.cypress-results.outcome }}. See results at ${{ steps.cypress-results.outputs.dashboardUrl }}'
        env:
          GITHUB_TOKEN: dispatch token

问题根源在于run-cypress-tests任务的Checkout步骤——你没指定要检出的分支，默认会拉取仓库的默认分支（也就是master）。要让测试针对staging分支运行，按以下方式修改：

方案一：直接拉取固定的staging分支 #

如果你的staging分支是固定命名（比如就叫staging），直接修改run-cypress-tests里的Checkout步骤，指定ref参数：

- name: Checkout 
  uses: actions/checkout@v2
  with:
    ref: staging
    token: dispatch token # 确保这个token有权限拉取staging分支

方案二：关联PR对应的代码分支（如果PR已合并到staging） #

如果Successful Gordon Deploy评论表示当前PR的代码已经合并到staging，或者你需要测试PR本身的代码（对应staging环境），可以把identify-staging-deploy中获取的分支信息传递给测试任务：

1. 在identify-staging-deploy任务添加输出配置，把分支和仓库名传出去：

jobs:
  identify-staging-deploy:
    runs-on: ubuntu-latest
    name: deploy to staging comment on pr
    if: contains(github.event.comment.body, 'Successful Gordon Deploy')
    outputs:
      branch: ${{ steps.pr_info.outputs.branch }}
      repo_name: ${{ steps.pr_info.outputs.repo_name }}
    # 原有的步骤保持不变

2. 在run-cypress-tests的Checkout步骤中使用传递过来的参数：

run-cypress-tests:
  needs: identify-staging-deploy
  runs-on: ubuntu-latest
  steps:
    - name: Checkout 
      uses: actions/checkout@v2
      with:
        repository: ${{ needs.identify-staging-deploy.outputs.repo_name }}
        ref: ${{ needs.identify-staging-deploy.outputs.branch }}
        token: dispatch token
    # 原有的其他步骤保持不变

额外修正：修复PR评论中的仓库名错误 #

你在Post PR Comment步骤里写死了repo_name，应该用${{ github.repository }}动态获取当前仓库，避免硬编码出错：

/repos/${{ github.repository }}/issues/${{ github.event.issue.number }}/comments

内容的提问来源于stack exchange，提问作者Rinkala