## Problem to solve When the source and target branch contain a conflict, [`UserMergeToRef`](https://gitlab.com/gitlab-org/gitlab/-/blob/88f5d2e16cf12d08e4562a155808f942abc9261f/app/services/merge_requests/merge_to_ref_service.rb#L69) is likely to fail. Within https://gitlab.com/gitlab-org/gitlab/-/issues/232484 we've introduced `AllowConflicts` param which let `UserMergeToRef` succeed when [both-modified](https://gitlab.com/groups/gitlab-org/-/epics/4893#1-both-modified-the-same-file) conflict appears. In order to handle most of the classes of conflicts in a diff, we need to successfully merge to ref in case those classes of conflicts appear. ## Proposal - https://gitlab.com/gitlab-org/gitaly/-/merge_requests/2626 started merging conflicts with markers directly in diff - https://gitlab.com/gitlab-org/gitaly/-/merge_requests/2997 is porting the functionality to Golang Instead of merging markers into the diff, we could consider the option of resolving the conflicts by merging _our_ changes to the diff. That will allow us to merge to ref even if there are conflicts. After that, the conflicts can be displayed on diff by using Gitaly Conflicts API, just like we've implemented it here: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/47003 Edit notes: Replaced the MR for "porting the functionality to Golang" with a different one because the old one (https://gitlab.com/gitlab-org/gitaly/-/merge_requests/2642) was closed and implemented in a different MR. <!-- triage-serverless v3 PLEASE DO NOT REMOVE THIS SECTION --> *This page may contain information related to upcoming products, features and functionality. It is important to note that the information presented is for informational purposes only, so please do not rely on the information for purchasing or planning purposes. Just like with all projects, the items mentioned on the page are subject to change or delay, and the development, release, and timing of any products, features, or functionality remain at the sole discretion of GitLab Inc.* <!-- triage-serverless v3 PLEASE DO NOT REMOVE THIS SECTION -->