Any way to checkout PR from issue_comment event?

[aaronsteers]

The example in the docs here assumes a pull request event, but it does not work when operating on Pull Request comments, since those come through the issue_comment event.

I've spent several hours on this now and I don't see any way to checkout the branch associated with the issue_event.

Complications:

• The event is the comment and it links to an issue, which only indirectly seems to have data on the pull request url.
• Checking out the associate sha doesn't give push ability, since the branch name itself is not discoverable (at least not as well as I can tell).
• Since issue_comment events have to be triggered by the workflow file on the default branch, it seems that is always the branch name provided. I haven't yet found any way to get the actual PR branch, although it seems this should be a straightforward and frequent use case for operating on PR comments.

[aaronsteers]

The only solution I found was to first use the checkout event and then separately use hub CLI, which is apparently installed by default and which can run hub pr checkout ${pr_num} in order to checkout whatever branch is associated with the PR (after parsing the PR num from the URL).

name: Slash Command CI

on: issue_comment

jobs:
  check_comments:
    runs-on: ubuntu-latest
    name: Check comments for /format
    steps:
      - name: Clone git repo
        uses: actions/checkout@v2
      - name: Checkout Pull Request
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          PR_URL="${{ github.event.issue.pull_request.url }}"
          PR_NUM=${PR_URL##*/}
          echo "Checking out from PR #$PR_NUM based on URL: $PR_URL"
          hub pr checkout $PR_NUM
      - name: Configure Git Agent
        run: |
          git config --global user.email "[email protected]"
          git config --global user.name "Me, Not Really (CI bot)"
      - uses: hashicorp/setup-terraform@v1
        with:
          terraform_version: 0.13.0
      - run: terraform fmt -recursive
      - run: git commit -a -m "GitOps Bot (Autoformat)"
      - run: git push

Is there a better way?

[NutanNiraula]

I faced the same problem with one more restriction that github account was not owned by us, I don't know the context that other users will face but in my case I can just send in the branch name through the comment. so, here is what I did:

Basically pull out branch name from comment where branch name is enclosed in [], i.e [branch_name] then extract out the name to pass it to the checkout action. I would love to find better way than this but for now it works ok.

steps:
    - name: Get Branch name
      id: branchName
      run: |
        echo ::set-output name=branch::$(echo $PR_COMMENT | cut -d "[" -f2 | cut -d "]" -f1)
      env:
        PR_COMMENT: ${{ github.event.comment.body }}
    - name: Checkout code
      uses: actions/checkout@v2
      with: 
        ref: ${{ steps.branchName.outputs.branch }}

[Simran-B]

As the required information isn't present in the event payload, you could use the GitHub API to fetch it. The github-script action allows you to write actions in your workflow file, which is pretty convenient:

name: Checkout PR on comment

on:
  issue_comment:
    # triggers on created, edited and deleted by default, you may wanna restrict it, e.g.:
    #types: [created]
jobs:
  pr-commented:
    name: PR commented
    if: github.event.issue.pull_request
    runs-on: ubuntu-latest
    steps:
      - uses: actions/github-script@v3
        id: get-pr
        with:
          script: |
            const request = {
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: context.issue.number
            }
            core.info(`Getting PR #${request.pull_number} from ${request.owner}/${request.repo}`)
            try {
              const result = await github.pulls.get(request)
              return result.data
            } catch (err) {
              core.setFailed(`Request failed with error ${err}`)
            }
      - uses: actions/checkout@v2
        with:
          repository: ${{ fromJSON(steps.get-pr.outputs.result).head.repo.full_name }}
          ref: ${{ fromJSON(steps.get-pr.outputs.result).head.sha }} # or .head.ref for branch name

[zyv]

The only solution I found was to first use the checkout event and then separately use hub CLI, which is apparently installed by default and which can run hub pr checkout ${pr_num} in order to checkout whatever branch is associated with the PR (after parsing the PR num from the URL).

Is there a better way?

@aaronsteers do you even need to parse it? I though the following should do:

hub pr checkout ${{ github.event.issue.number }}

[aaronsteers]

The only solution I found was to first use the checkout event and then separately use hub CLI, which is apparently installed by default and which can run hub pr checkout ${pr_num} in order to checkout whatever branch is associated with the PR (after parsing the PR num from the URL).

Is there a better way?

@aaronsteers do you even need to parse it? I though the following should do:

hub pr checkout ${{ github.event.issue.number }}

@zyv , yes, I think it would! The 10-months-ago-me perhaps didn't know or realize yet that a PR is an issue and the issue number is therefore the same as the PR number. 🙌

[rongquantoh-intel]

Can we add PR information like target branch or source branch in issue_comment webhook payload?
These should be very commonly used.

[mareksuscak]

The only solution I found was to first use the checkout event and then separately use hub CLI, which is apparently installed by default and which can run hub pr checkout ${pr_num} in order to checkout whatever branch is associated with the PR (after parsing the PR num from the URL).
Is there a better way?

@aaronsteers do you even need to parse it? I though the following should do:

hub pr checkout ${{ github.event.issue.number }}

This has worked for us!

deploy:
  runs-on: ubuntu-latest
  steps:
    # Checkout source code
    - name: Checkout
      uses: actions/checkout@v2
    - name: Checkout Pull Request
      run: hub pr checkout ${{ github.event.issue.number }}
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

[tomdottom]

Edit: The below information is not correct as pointed out by @zyv below

- uses: actions/checkout@v2
  with:
    ref: ${{ github.event.pull_request.head.sha }}

• https://frontside.com/blog/2020-05-26-github-actions-pull_request/

[zyv]

@tomdottom this information is not available in issue_comment event.

[tomdottom]

@tomdottom this information is not available in issue_comment event.

@zyv thanks for pointing this out

[suonto]

I just created a tiny js action that will output base_ref and head_ref: https://github.com/eficode/resolve-pr-refs

It's really simple to use:

- name: resolve pr refs
  id: refs
  uses: eficode/resolve-pr-refs@main
  with:
    token: ${{ secrets.GITHUB_TOKEN }}

In the following steps you can reference ${{ steps.refs.outputs.head_ref }} and ${{ steps.refs.outputs.base_ref }}

I hope you like it 🙂

[jacobrask]

In case anyone else comes looking, you can use the gh cli to only get the branch name if you still want to use the actions/checkout action

    steps:
      - id: 'get-branch'
        run: echo ::set-output name=branch::$(gh pr view $PR_NO --repo $REPO --json headRefName --jq '.headRefName')
        env:
          REPO: ${{ github.repository }}
          PR_NO: ${{ github.event.issue.number }}
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - name: Checkout
        uses: actions/checkout@v2
        with:
          ref: ${{ steps.get-branch.outputs.branch }}

[AllanOricil]

@jacobrask I tried your solution and I received the following output:

GraphQL: Resource not accessible by integration (repository.pullRequest)

What else did you do?

[NickCrews]

@mareksuscak's method worked great for my on: issue_comment triggered workflow. Pretty sure you can't get much shorter or faster than this!

deploy:
  runs-on: ubuntu-latest
  steps:
    # need this first step to init the git repo
    - name: Checkout
      uses: actions/checkout@v2
    - name: Checkout Pull Request
      run: hub pr checkout ${{ github.event.issue.number }}
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

[ADTC]

Great discovery @Zhiyuan-Amos I will add your comment in my PR if that's okay with you.

[dcantu96]

has anyone found a way to find the ref of the pr with this issue_comment trigger event ?

as far as I know github.event.issue.pull_request.ref doesnt work :/ i'd like a solution that avoids using octokit

[hakuno]

Hey everybody, I noticed that GitHub creates refs for pull request commits: https://www.jvt.me/posts/2019/01/19/git-ref-github-pull-requests/ This allows to checkout the branch of the pull request directly in the actions/checkout@v3 action:

      - name: Checkout pull request 🏁
        uses: actions/checkout@v3
        with:
          ref: refs/pull/${{ github.event.issue.number }}/head

I changed that for me to support both triggers (issue_comment or any other like workflow_dispatch):

- uses: actions/checkout@v4
  with:
    ref: ${{ github.event_name == 'issue_comment' && format('refs/pull/{0}/head', github.event.issue.number) || '' }}

[justinhenricks]

What worked for me was simply

            - name: Checkout PR branch
              run: |
                  gh pr checkout ${{ github.event.issue.number }}
              env:
                  GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}

[arunstar]

When using the issue_comment event to check out a PR, exercise caution because the auto-generated GITHUB_TOKEN grants write access to the repository. Ensure the PR originates from a trusted user to prevent potential security risks.

[Maker-Mark]

Hey everybody, I noticed that GitHub creates refs for pull request commits: https://www.jvt.me/posts/2019/01/19/git-ref-github-pull-requests/ This allows to checkout the branch of the pull request directly in the actions/checkout@v3 action:

      - name: Checkout pull request 🏁
        uses: actions/checkout@v3
        with:
          ref: refs/pull/${{ github.event.issue.number }}/head

For what it's worth, there's a chance the ref will no longer exist if the PR is closed. If you want an action to try to check out the open pr's branch you can just check the state of the issue's state. If the pr is open, the branch will exist.

You can do something like:

if: ${{ github.event.issue.state }} == "open" 

or

      - name: ref
        id: my-ref
        run: |
          if [[ "${{ github.event.issue.state }}" == "open" ]]; then
            echo "::set-output name=ref::refs/pull/${{ github.event.issue.number }}/head"
          else
            echo "::set-output name=ref::main"
          fi