PR Target Branch Action

A GitHub action to check that a PR's target branch is correct, commenting and/or changing it if required

Example usage

Please note using pull_request_target can be dangerous, read GitHub's security article here before using examples with it

name: Make sure new PRs are sent to development

on:
  pull_request_target: # Please read https://securitylab.github.com/research/github-actions-preventing-pwn-requests/ before using
    types: [opened, edited]

jobs:
  check-branch:
    runs-on: ubuntu-latest
    steps:
      - uses: Vankka/pr-target-branch-action@v2
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        with:
          target: main
          exclude: development # Don't prevent going from development -> main
          change-to: development
          comment: |
              Your PR was set to target `main`, PRs should be target `development`
              The base branch of this PR has been automatically changed to `development`, please check that there are no merge conflicts

When change-to, comment, already-exists-action, already-exists-comment and already-exists-other-comment are not used, pull_request_target and the GITHUB_TOKEN are not required. The Action will just fail (instead of changing the base branch or commenting) when the target branch is wrong.

name: Make sure new PRs are sent to development

on:
  pull_request:
    types: [opened, edited]

jobs:
  check-branch:
    runs-on: ubuntu-latest
    steps:
      - uses: Vankka/pr-target-branch-action@v2
        with:
          target: main
          exclude: development # Don't prevent going from development -> main

Full example

Contains all the options, not necessarily a good configuration - see already-exists-action for more details

name: Make sure new PRs are sent to development

on:
  pull_request_target: # Please read https://securitylab.github.com/research/github-actions-preventing-pwn-requests/ before using
    types: [opened, edited]

jobs:
  check-branch:
    runs-on: ubuntu-latest
    steps:
      - uses: Vankka/pr-target-branch-action@v2
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        with:
          target: main
          exclude: development # Don't prevent going from development -> main
          change-to: development
          comment: |
              Your PR was set to target `main`, PRs should be target `development`
              The base branch of this PR has been automatically changed to `development`, please check that there are no merge conflicts
          already-exists-action: close_other_continue
          already-exists-comment: "Closing {url} as it has the same base branch"
          already-exists-other-comment: "This PR was closed in favor of {url}"

Variables

target (Required)

The base branch this action will check for, this also accepts a Regular Expression (pre- and suffixed with /, the pattern should match only the branch name), example values:

# Only matches the development branch
development

# Match all branches matching the pattern: feature-\w+
/feature-\\w+/

Multiple values can be provided with a string of values separated by spaces, example:

include: "main development v1"

include

Head (or compare) branch(es) that are subject to checking, can be provided with a branch name, organization/owner name:branch name or a Regular Expression matching the latter. Also supports providing multiple targets by using spaces. Example values:

# Match the target project's branch called development
development

# Only match GitHub's development branch
GitHub:development

# Match PRs from all of GitHub's branches 
/GitHub:.*/

Multiple values can be provided with a string of values separated by spaces, example:

include: "main development v1"

exclude

Head (or compare) branch(es) that will not be checked, can be provided with a branch name, organization/owner name:branch name or a Regular Expression matching the latter. Also supports providing multiple targets by using spaces. Example values:

# Match the target project's branch called development
development

# Only match GitHub's development branch
GitHub:development

# Match PRs from all of GitHub's branches 
/GitHub:.*/

Multiple values can be provided with a string of values separated by spaces, example:

exclude: "main development v1"

change-to

What the PRs base branch should be changed to if the base branched matches the given criteria.

Requires using the pull_request_target event and including the GITHUB_TOKEN environment variable

comment

The comment to post if the base branch matches the given criteria.

Requires using the pull_request_target event and including the GITHUB_TOKEN environment variable

already-exists-action

Only if change-to is specified, the action to take if another open PR with the same head & base branches exists

error

The action simply fails, this is the default value

close_this

Closes this PR

close_other

Closes the other PR. Keep in mind this ignores if the other pr was created by someone else.

close_other_continue

Closes the other PR, and processes change-to and comment as normal. Keep in mind this ignores if the other pr was created by someone else.

nothing

Nothing special happens, already-exists-comment will be posted if it is specified

already-exists-comment

Only if change-to is specified, the comment to post if another open PR with the same head & base branches exists.

Use {number} to get the pull request number or {url} to get the pull request link for the other pr.

already-exists-other-comment

The comment to post on the other pr if a pr is closed due to already-exists-action being set to close_other or close_other_continue.

Use {number} to get the pull request number or {url} to get the pull request link for the pr that wasn't closed.