Overview page has "Checking pipeline status" never ending spinner

Summary

As surfaced by this automated test: #397657 (comment 1320269304) in master pipeline

As we now load diffs asynchronously, if a user creates an MR sometimes the Overview tab will have "Checking pipeline status" for over a minute (test times out after a minute). The user must refresh the page after the diff has loaded to see the expected Overview page.

The logs from the browser indicate a 404, [404] GET /gitlab-qa-sandbox-group-4/qa-test-2023-03-22-02-12-33-5518e7d088a67132/importedproject-6d8567e9d7ed9ea2/-/merge_requests/2/diffs_metadata.json -- Correlation Id: 01GW3HR46KW2XPW4ZSP020MVAS

Steps to reproduce

Note: does not always occur

  1. Create a large MR via UI
  2. Revert the MR
  3. Overview tab should be displayed

Example Project

Any

What is the current bug behavior?

User must refresh page for spinner to finish.

create_merged_merge_request_can_be_reverted_2023-03-22-03-56-37.360

What is the expected correct behavior?

Pipeline status eventually loads

Possible fixes

Edited by Allison Browne