Can't change target branch or view comments after parent MR merges

What

  • Merge requests can get into a state where comments are not shown, along with not showing the sidebar to allow changing details such as assignee.
  • Changing the target branch is hard enough I thought it impossible in this state. The /target_branch quick action didn't work from an MR description. It turns out the target branch selection had moved to the top above the description field, but I was unable to find it there.

Steps to reproduce

  1. Create an MR that has multiple commits
  2. Decided to split the MR into multiple. Create a second MR for the latest commits and reset the first MR to an earlier commit.
  3. Update the new MR to set the initial one as its target, so as to reduce the diff shown.
  4. Eventually merge the first MR with the option to delete the source branch ticked
  5. Rebase the first MR on master now changes have merged
  6. Attempt to visit the MR and update the target branch

Expected outcome

Page displays as normal, possibly without the diff and comments on the diff greyed out, but ideally in full.

Changing the target branch is easy and obvious

Actual outcome

Page is stuck in a weird failed state. The other things on the MR I might have changed or commented on are gone. I can't use the sidebar. I can't use quick actions because the comments box is gone. Quick action from edit page doesn't work. I can't find a way to change target branch.

Possible solutions

  • Could we display a change target branch form below the error message?
  • Could we still display comments/pipelines/sidebar?

Screen capture

screencap_2019-11-06-03_45_50

Assignee Loading
Time tracking Loading