Fast and flexible GitHub action to backport merged pull requests to selected branches.
This can be useful when you're supporting multiple versions of your product. After fixing a bug, you may want to apply that patch to the other versions. The manual labor of cherry-picking the individual commits can be automated using this action.
- Works out of the box - No configuration required / Defaults for everything
- Fast - Only fetches the bare minimum / Supports shallow clones
- Flexible - Supports all merge methods including merge queue and Bors
- Configurable - Use inputs and outputs to fit it to your project
- Transparent - Informs about its success / Cherry-picks with
-x
You can select the branches to backport merged pull requests in two ways:
- using labels on the merged pull request.
The action looks for labels on your merged pull request matching the
label_pattern
input - using the
target_branches
input
For each selected branch, the backport action takes the following steps:
- fetch and checkout a new branch from the target branch
- cherry-pick the merged pull request's commits
- create a pull request to merge the new branch into the target branch
- comment on the original pull request about its success
Add the following workflow configuration to your repository's .github/workflows
folder.
name: Backport merged pull request
on:
pull_request_target:
types: [closed]
permissions:
contents: write # so it can comment
pull-requests: write # so it can create pull requests
jobs:
backport:
name: Backport pull request
runs-on: ubuntu-latest
# Don't run on closed unmerged pull requests
if: github.event.pull_request.merged
steps:
- uses: actions/checkout@v4
- name: Create backport pull requests
uses: korthout/backport-action@v2
Note This workflow runs on
pull_request_target
so thatGITHUB_TOKEN
has write access to the repo when the merged pull request comes from a forked repository. This write access is necessary for the action to push the commits it cherry-picked.
You can also trigger the backport action by writing a comment containing /backport
on a merged pull request.
To enable this, add the following workflow configuration to your repository's .github/workflows
folder.
Trigger backport action using a comment
name: Backport merged pull request
on:
pull_request_target:
types: [closed]
issue_comment:
types: [created]
permissions:
contents: write # so it can comment
pull-requests: write # so it can create pull requests
jobs:
backport:
name: Backport pull request
runs-on: ubuntu-latest
# Only run when pull request is merged
# or when a comment starting with `/backport` is created by someone other than the
# https://github.com/backport-action bot user (user id: 97796249). Note that if you use your
# own PAT as `github_token`, that you should replace this id with yours.
if: >
(
github.event_name == 'pull_request_target' &&
github.event.pull_request.merged
) || (
github.event_name == 'issue_comment' &&
github.event.issue.pull_request &&
github.event.comment.user.id != 97796249 &&
startsWith(github.event.comment.body, '/backport')
)
steps:
- uses: actions/checkout@v4
- name: Create backport pull requests
uses: korthout/backport-action@v2
The action can be configured with the following optional inputs:
Default: false
(disabled)
Controls whether to copy the assignees from the original pull request to the backport pull request. By default, the assignees are not copied.
Default: ''
(disabled)
Regex pattern to match github labels which will be copied from the original pull request to the backport pull request.
Note that labels matching label_pattern
are excluded.
By default, no labels are copied.
Default: false
(disabled)
Controls whether to copy the milestone from the original pull request to the backport pull request. By default, the milestone is not copied.
Default: false
(disabled)
Controls whether to copy the requested reviewers from the original pull request to the backport pull request. Note that this does not request reviews from those users who already reviewed the original pull request. By default, the requested reviewers are not copied.
Default:
{
"detect_merge_method": false
}
Configure experimental features by passing a JSON object. The following properties can be specified:
Default: false
When enabled, the action detects the method used to merge the pull request.
- For "Squash and merge", the action cherry-picks the squashed commit.
- For "Rebase and merge", the action cherry-picks the rebased commits.
- For "Merged as a merge commit", the action cherry-picks the commits from the pull request.
By default, the action always cherry-picks the commits from the pull request.
Default: ${{ github.token }}
Token to authenticate requests to GitHub. Used to create and label pull requests and to comment.
Either GITHUB_TOKEN
or a repo-scoped Personal Access Token (PAT).
Default: ${{ github.workspace }}
Working directory for the backport action.
Default: ^backport ([^ ]+)$
(e.g. matches backport release-3.4
)
Regex pattern to match the backport labels on the merged pull request.
Must contain a capture group for the target branch.
Label matching can be disabled entirely using an empty string ''
as pattern.
The action will backport the pull request to each matched target branch. Note that the pull request's headref is excluded automatically. See How it works.
Default: fail
Specifies how the action should deal with merge commits on the merged pull request.
- When set to
fail
the backport fails when the action detects one or more merge commits. - When set to
skip
the action only cherry-picks non-merge commits, i.e. it ignores merge commits. This can be useful when you keep your pull requests in sync with the base branch using merge commits.
Default:
# Description
Backport of #${pull_number} to `${target_branch}`.
Template used as description (i.e. body) in the pull requests created by this action.
Placeholders can be used to define variable values.
These are indicated by a dollar sign and curly braces (${placeholder}
).
Please refer to this action's README for all available placeholders.
Default: [Backport ${target_branch}] ${pull_title}
Template used as the title in the pull requests created by this action.
Placeholders can be used to define variable values.
These are indicated by a dollar sign and curly braces (${placeholder}
).
Please refer to this action's README for all available placeholders.
Default: ''
(disabled)
The action will backport the pull request to each specified target branch (space-delimited). Note that the pull request's headref is excluded automatically. See How it works.
Can be used in addition to backport labels. By default, only backport labels are used to specify the target branches.
In the pull_description
and pull_title
inputs, placeholders can be used to define variable values.
These are indicated by a dollar sign and curly braces (${placeholder}
).
The following placeholders are available and are replaced with:
Placeholder | Replaced with |
---|---|
issue_refs |
GitHub issue references to all issues mentioned in the original pull request description seperated by a space, e.g. #123 #456 korthout/backport-action#789 |
pull_author |
The username of the original pull request's author, e.g. korthout |
pull_description |
The description (i.e. body) of the original pull request that is backported, e.g. Summary: This patch was created to.. |
pull_number |
The number of the original pull request that is backported, e.g. 123 |
pull_title |
The title of the original pull request that is backported, e.g. fix: some error |
target_branch |
The branchname to which the pull request is backported, e.g. release-0.23 |
The action provides the following outputs:
Output | Description |
---|---|
created_pull_numbers |
Space-separated list containing the identifying number of each created pull request. Or empty when the action created no pull requests. For example, 123 or 123 124 125 . |
was_successful |
Whether or not the changes could be backported successfully to all targets. Either true or false . |
was_successful_by_target |
Whether or not the changes could be backported successfully to all targets - broken down by target. Follows the pattern {{label}}=true|false . |