Github Action to remove previous job PR comments

2024-09-23 (Monday) | 200 words (~1 minutes reading)

Here’s a Github Action that finds and removes PR comments based on a string identifier. This is useful for Github Action workflows that post comments to PRs, as it clears up out-of-date comments from earlier workflow runs.

name: Command & Comment
description: Run a bash command and comment failure output back to PR
inputs:
  identifier:
    description: Single word identifier for comments to remove
    required: true
runs:
  using: "composite"
  steps:
    - name: Remove previous job comments
      uses: actions/github-script@v7
      with:
        script: |
          const pr_comments = await github.rest.issues.listComments({
            owner: context.repo.owner,
            repo: context.repo.repo,
            issue_number: context.issue.number,
          })
          await Promise.all(
            pr_comments.data.filter(
              comment => comment.body?.startsWith("[${{inputs.identifier}}]")
            ).map(
              comment => github.rest.issues.deleteComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.issue.number,
                comment_id: comment.id,
              })
            )
          )

It removes comments on the PR it is running against if the comment begins with [{identifier}]. If other comments happen to begin with that then they will also be removed. More checks could be added to the filter to avoid this if it’s a problem on a particular project.

The key part of the Github Action is the Github Script step:

const pr_comments = await github.rest.issues.listComments({
  owner: context.repo.owner,
  repo: context.repo.repo,
  issue_number: context.issue.number,
})
await Promise.all(
  pr_comments.data.filter(
    comment => comment.body?.startsWith("[${{inputs.identifier}}]")
  ).map(
    comment => github.rest.issues.deleteComment({
      owner: context.repo.owner,
      repo: context.repo.repo,
      issue_number: context.issue.number,
      comment_id: comment.id,
    })
  )
)

You can call this action from another workflow like this:

# ...
jobs:
  foobar:
    steps:
      - name: Remove previous foobar comments
        uses: ./.github/actions/remove_comments
        with:
          identifier: foobar

Tech mentioned