Merge Request loading widget issues causing widespread E2E test failures

Summary

We are experiencing widespread E2E test failures across multiple test suites due to merge request pages not fully loading. This issue is causing significant test flakiness and requires investigation to address the underlying problem.

Problem Description

Multiple E2E tests are failing with error:

QA::Support::Repeater::WaitExceededError:
  Page did not fully load: Spinner still visible (AJAX requests completed)

QA::Support::Repeater::WaitExceededError:
  Page did not fully load. This could be due to an unending async request or loading icon.

Failure Examples:

The following test failure issues have been reported recently -

• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/1445
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/1502
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/1228
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/8745
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/6831
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/8366
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/6849
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/1491
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/7302
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/7103
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/6839
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/1450
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/1796
• https://gitlab.com/gitlab-org/quality/test-failure-issues/-/issues/1559

Failures are observed in master, live environment, and causing sanity check to fail.

Step To Reproduce (by @jay_mccure)

1. create an MR (keep this tab open),
2. add a commit to the source branch and click rebase from the merge widget from the original tab
3. It will take over a minute for the Approvals spinner to disappear

Investigation

1. Have there been recent changes to the merge request widget that could explain the increased loading times?
2. There seems to be some flakiness around longer loading time for MR tabs ( Example 1, 2, 3). Is this a part of a larger performance issue that needs to be addressed?

Related Links

• Slack discussion (by @jay_mccure)
  • rebase_on_merge_automatic feature flag has been ruled out