Update Branch is an Always Be Closing (ABC) feature that automatically updates pull requests. When there is a new commit to the base branch, the service will merge those commits into the compare branch. If there are merge conflicts then it does not merge. If the compare branch is a protected branch then it does not merge.
Here is an example of the feature. The commit
484243b was added by
the ABC service.
The compare branch must be in the same repository as the base branch. This feature does not work on pull requests made across repository forks. As of November 2018, GitHub does not provide an API to invoke the “Update Pull Request” button that is available in the UI. The Merge API does not allow merges across different repositories.
This feature requires write access to the git contents of your repository. Due to this requirement the feature is not available in the “Always Be Closing Jr” service. ABC Jr only provides features that do not require read/write access to contents of the git repository.