"Open a PR" action?

[defung]

Is there a way for Mergify to open a PR? Our team has a unique workflow. Would love to use mergify to automate some of these tasks.

We primarily have 2 branches: main, and release/<version> (e.g. release/1.23)

Our main branch is more like a dev branch, where most of our new changes go into. Once in a while, we have a bug fix, where we will fix directly in release/<version>. Once the bug fix is merged into release/<version>, we then do a merge from release/<version> branch back to main. This way, the bug fix will also be in main, AND we retain the original git commit hash.

Its sort of like backport, but from what I read, backport does a cherry pick, which isn't something we want. We want to retain the commit hash of the original merge to the release/<version> branch, but a cherry pick would generate a new commit hash.

So therefore, I want to create a rule with Mergify that does the above automatically. However, I'm not sure if its possible after reading the documentation.

I would need the following features in order to do this:

1. an action that can open a Pull Request
2. a way to get the current branch name

If there's such a way, it might look something like this:

pull_request_rules:
  - name: Bug fix merge
    conditions:
      - "#approved-reviews-by>=2"
      - check-success=Travis CI - Pull Request
      - base=release/*
      - label=ready-to-merge
    actions:
      merge:
        method: squash
      create_pr:      # <--- We need an action that would create a new PR
        - base=main
        - branch=<this_pr's_base_branch>  # <--- We also need a way to get the current PR's base branch name, so we can use it here
  - name: Automated release to Main merge
    conditions:
      - author=<mergify_user>
      - check-success=Travis CI - Pull Request
      - base=main
      - branch_name=release/*  # <--- would also need an attribute to match against the branch name of the PR
    actions:
      merge:
        method: merge
  - name: delete head branch after merge
    conditions:
      - merged
      - branch_name=release/*  # <--- same here
    actions:
      delete_head_branch:

Can you let me know if something like this is possible with mergify?

[sileht]

What you call branch_name is the attribute head, so you can write with a regex something like head~=release/.*.

We don't have a create_pr but we have seen you can use backport or copy action. And yes It uses cherry-pick under the hood and doesn't preserve sha1 of commits.

I don't see how we can keep the same sha1 with your workflow, Git needs that the two branches have exactly the same history to do that or you need to use a merge commit and may embark commits that are not part of the initial pull request.

Mergify is focused on pull requests, while you want something to keep your main branch in sync with your release branch.

Maybe you can use something https://github.com/wei/pull, you can configure it to create a pull request of all changes in release/.* to you main branch with a merge commit (sha1 are preserved). And create a Mergify rule to auto-merge this pull request.

[defung]

Interesting... thanks for the insightful analysis! will definitely take a look at wei/pull and see if this would work for us!