<!--- Please read this! Before opening a new issue, make sure to search for keywords in the issues filtered by the "regression" or "type::bug" label: - https://gitlab.com/gitlab-org/gitlab/issues?label_name%5B%5D=regression - https://gitlab.com/gitlab-org/gitlab/issues?label_name%5B%5D=type::bug and verify the issue you're about to submit isn't a duplicate. ---> ### Summary <!-- Summarize the bug encountered concisely. --> After merging an MR, the commits that appear on the main branch are not displayed in the MR itself. The MR shows zero commits and the Changes tab appears empty, despite the MR containing 3-4 commits. ### Steps to reproduce 1. Navigate to this specific MR: https://gitlab.com/gitlab-org/technical-writing/docs-gitlab-com/-/merge_requests/1645 2. Check the Commits tab → Shows 0 commits 3. Check the Changes tab → Shows empty 4. Navigate to main branch → Commits are visible ### What is the current *bug* behavior? * MR displays 0 commits * Changes tab is empty * Commits are visible on main after merge ### What is the expected *correct* behavior? * MR should display all commits (3-4 commits in this case) * Changes tab should show the diff of all changes ### Additional observations * When visiting the MR and clicking the diff versions dropdown, all versions show as selected (should only select latest by default) * When clicking "latest" version, the diff displays correctly. The commits are still not displayed. * Not related to diff commit deduplication work (only enabled for 3 internal projects as of today, #527239) {width=600 height=465} ### Relevant logs and/or screenshots <!-- Paste any relevant logs - please use code blocks (```) to format console output, logs, and code as it's tough to read otherwise. --> ### Possible fixes <!-- If you can, link to the line of code that might be responsible for the problem. --> ### Patch release information for backports If the bug fix needs to be backported in a [patch release](https://handbook.gitlab.com/handbook/engineering/releases/patch-releases) to a version under [the maintenance policy](https://docs.gitlab.com/policy/maintenance/), please follow the steps on the [patch release runbook for GitLab engineers](https://gitlab.com/gitlab-org/release/docs/-/blob/master/general/patch/engineers.md). Refer to the [internal "Release Information" dashboard](https://dashboards.gitlab.net/d/delivery-release_info/delivery3a-release-information?orgId=1) for information about the next patch release, including the targeted versions, expected release date, and current status. #### High-severity bug remediation To remediate high-severity issues requiring an [internal release](https://handbook.gitlab.com/handbook/engineering/releases/internal-releases/) for single-tenant SaaS instances, refer to the [internal release process for engineers](https://gitlab.com/gitlab-org/release/docs/-/blob/master/general/internal-releases/engineers.md?ref_type=heads). <!-- If you don't have /label privileges, follow up with an issue comment of `@gitlab-bot label ~"type::bug"` -->