probot-auto-merge

A GitHub App built with Probot that automatically merges PRs

Usage

Configure the GitHub App
Create .github/auto-merge.yml in your repository.
Customize configuration to your needs. See below.

Configuration

Configuration of probot-auto-merge is done through .github/auto-merge.yml in your repository. An example of this file can be found here. You can also see the configuration for this repository here.

The configuration has values that serve as conditions on whether or not a pull request should be automatically merged and also configuration about the merge itself. Values that serve as conditions are annotated as such below.

All conditions must be met before a PR will be automatically merged. You can get more flexibility by defining multiple rules. Rules can have multiple conditions and if any of the conditions inside a rule are met, the PR is also merged. See rules.

If the target branch is a protected branch, you must add probot-auto-merge bot to the list of People, teams or apps with push access in your branch protection rules.

Note that the default configuration options are to do nothing. This is to prevent implicit and possibly unintended behavior.

The configuration fields are as follows:

`minApprovals` (required, condition)

The minimum number of reviews from each association that approve the pull request before doing an automatic merge. For more information about associations see: https://developer.github.com/v4/enum/commentauthorassociation/

Possible associations: OWNER, MEMBER, COLLABORATOR, CONTRIBUTOR, FIRST_TIMER, FIRST_TIME_CONTRIBUTOR, NONE

In the example below when a pull request gets 2 approvals from owners, members or collaborators, the automatic merge will continue.

minApprovals:
  COLLABORATOR: 2

In the example below when a pull request gets 1 approval from an owner OR 2 approvals from members, the automatic merge will continue.

minApprovals:
  OWNER: 1
  MEMBER: 2

`requiredReviewers` (condition, default: none)

Whenever required reviewers are configured, pull requests will only be automatically merged whenever all of these reviewers have approved the pull request.

In the example below, pull requests need to have been approved by the user 'rogerluan' before they will be automatically merged.

requiredReviewers:
- rogerluan

`maxRequestedChanges` (condition, default: none)

Similar to minApprovals, maxRequestedChanges determines the maximum number of requested changes before a pull request will be blocked from being automatically merged.

It yet again allows you to configure this per association.

Note that maxRequestedChanges takes precedence over minApprovals.

In the example below, automatic merges will be blocked when one of the owners, members or collaborators has requested changes.

maxRequestedChanges:
  COLLABORATOR: 0

In the example below, automatic merges will be blocked when the owner has requested changes or two members, collaborators or other users have requested changes.

maxRequestedChanges:
  OWNER: 0
  NONE: 1

The default for this value is:

maxRequestedChanges:
  NONE: 0

`blockingLabels` (condition, default: none)

Blocking labels are the labels that can be attached to a pull request to make sure the pull request is not being merged automatically.

In the example below, pull requests that have the blocked label will not be merged automatically.

blockingLabels:
- blocked

The above example denotes literal label names. Regular expressions can be used to partially match labels. This can be specified by the regex: property in the configuration. The following example will block merging when a label is added that starts with the text blocked:

blockingLabels:
- regex: ^blocked

Note: remove the whole section when you're not using blocking labels.

`requiredLabels` (condition, default: none)

Whenever required labels are configured, pull requests will only be automatically merged whenever all of these labels are attached to a pull request.

In the example below, pull requests need to have the label merge before they will be automatically merged.

requiredLabels:
- merge

The above example denotes literal label names. Regular expressions can be used to partially match labels. This requires regex: property in the configuration. The following example will requires at least one label that starts with merge:

requiredLabels:
- regex: ^merge

Note: remove the whole section when you're not using required labels.

`blockingTitleRegex` (condition, default: none)

Whenever a blocking title regular expression is configured, pull requests that have a title matching the configured expression will not be automatically merged.

This is useful whenever pull requests with WIP in their title need to be skipped.

In the example below, pull requests with the word wip in the title will not be automatically merged. This also includes [wip], WIP or [WIP], but not swiping:

blockingTitleRegex: '\bWIP\b'

`requiredTitleRegex` (condition, default: none)

Whenever a required title regular expression is configured, only pull requests that have a title matching the configured expression will automatically be merged.

This is useful for forks, that can only create pull request text, no labels.

In the example below, pull requests with the title containing MERGE will be automatically merged. This also includes This also includes [merge], MERGE or [MERGE], but not submerge:

requiredTitleRegex: '\bMERGE\b'

`blockingBodyRegex` (condition, default: none)

Whenever a blocking body regular expression is configured, pull requests that have a body matching the configured expression will not be automatically merged.

This is useful whenever pull requests with a certain string in their body need to be skipped.

In the example below, pull requests with the body containing do-not-merge will not be automatically merged. This also includes labels: do-not-merge, LABELS: DO-NOT-MERGE or some more text, but do-not-merge, but not do-not-merge-just-kidding:

blockingBodyRegex: '(^|\\s)do-not-merge($|\\s)'

`requiredBodyRegex` (condition, default: none)

Whenever a required body regular expression is configured, only pull requests that have a body matching the configured expression will automatically be merged.

This is useful for forks, that can only create pull request text, no labels.

In the example below, pull requests with the body containing ok-to-merge will be automatically merged. This also includes labels: ok-to-merge, LABELS: OK-TO-MERGE or some more text, but ok-to-merge, but not not-ok-to-merge:

requiredBodyRegex: '(^|\\s)ok-to-merge($|\\s)'

`reportStatus` (default: `false`)

The status of the auto-merge process will be shown in each PR as a check. This can be especially useful to find out why a PR is not being merged automatically.

To enable status reporting, add the following to your configuration:

reportStatus: true

`updateBranch` (default: `false`)

Whether an out-of-date pull request is automatically updated. It does so by merging its base on top of the head of the pull request. This is similar to the behavior of the 'Update branch' button.

updateBranch is useful for repositories where protected branches are used and the option Require branches to be up to date before merging is enabled.

Note that this only works when the branch of the pull request resides in the same repository as the pull request itself.

In the example below automatic updating of branches is enabled:

updateBranch: true

`deleteBranchAfterMerge` (default: `false`)

Whether the pull request branch is automatically deleted. This is the equivalent of clicking the 'Delete branch' button shown on merged pull requests.

Note that this only works when the branch of the pull request resides in the same repository as the pull request itself.

In the example below automatic deletion of pull request branches is enabled:

deleteBranchAfterMerge: true

`mergeMethod` (default: `merge`)

In what way a pull request is merged. This can be:

merge: creates a merge commit, combining the commits from the pull request on top of the base of the pull request (default)
rebase: places the commits from the pull request individually on top of the base of the pull request
squash: combines all changes from the pull request into a single commit and places the commit on top of the base of the pull request

For more information see https://help.github.com/articles/about-pull-request-merges/

mergeMethod: merge

`mergeCommitMessage` (default: none)

Optionally specify the merge commit message format. The following template tags are supported:

{title}: The pull request title at the moment it is merged
{body}: The pull request body at the moment it is merged
{number}: The pull request number
{branch}: The name of the source branch
{commits}: A list of merged commits

When this option is not set, the merge commit message is controlled by GitHub and uses a combination of the title of the pull request when it was opened (note that later changes to the title are ignored) and a list of commits.

This settings is ignored when mergeMethod is set to rebase.

mergeCommitMessage: |
  {title} (#{number})
  {body}

`rules` (default: none)

Rules allow more flexibility configuring conditions for automatically merging. Each rule is defined by multiple conditions. All conditions inside a rule must be met before a rule triggers a merge. Any of the defined rules can trigger a merge individually.

An example of a configuration with 2 rules that will trigger a merge upon 1 approval from an owner or a merge label:

rules:
- minApprovals:
    OWNER: 1
- requiredLabels:
    - merge

This can be combined with conditions on global level, as the global conditions will take precedence. The following example will not trigger a merge when a PR has the blocking label, regardless what the rules say:

blockingLabels:
- blocking
rules:
- minApprovals:
    OWNER: 1
- requiredLabels:
    - merge

Note: remove the whole rules section when you're not using any rules.

`requiredAuthorRole` (default: none)

Using the requiredAuthorRole condition you can specify conditions based on the role of the pull request author. For instance, using rules, one can be more loose when the author is an owner, and more restrictive otherwise.

Here's an example of a configuration that requires acceptance of 2 owners or 1 owner if the other owner made the PR:

rules:
- requiredAuthorRole: OWNER
  minApprovals:
    OWNER: 1
- minApprovals:
    OWNER: 2

Development

Setup

# Install dependencies 
npm install
 
# Run typescript 
npm run build

Testing

npm run test

or during development:

npm run test:watch

Running

See https://probot.github.io/docs/development/#configuring-a-github-app

npm run build && npm run dev

Running on Docker

This will build and run the app on a container called probot-auto-merge:

npm run docker

To just build the container image:

npm run docker:build

To run the built image:

npm run docker:run

Running the linter

This will run the linter, pointing out the infractions, but it won't fix them automatically.

npm run lint

Deployment

To deploy probot-auto-merge yourself, please follow the guidelines defined by Probot on deploying GitHub applications.

The permissions and events needed for the app to function can be found below.

Permissions

Administration: Read-only
Checks: Read & write
Contents: Read & write
Issues: Read & write
Metadata: Read-only
Pull requests: Read & write
Commit statuses: Read-only
Members: Read-only

Events

Check run
Check suite
Label
Pull request
Pull request review
Pull request review comment
Status

Contributing

If you have suggestions for how probot-auto-merge could be improved, or want to report a bug, open an issue! We'd love all and any contributions.

For more, check out the Contributing Guide.