500 error on viewing todos

Summary

500 error on viewing my todos on GitLab.com

More details here:

Looks like one of my todos has a nil project

https://sentry.gitlap.com/gitlab/gitlabcom/issues/4140/

Relevant logs and/or screenshots

ActionView::Template::Error

undefined method `name_with_namespace' for nil:NilClass
app/views/dashboard/todos/index.html.haml in block in _app_views_dashboard_todos_index_html_haml__805888156502021069_70055987718240 at line 53

mentioned in issue #17869 (closed)

Looks like many projects are stuck in pending_delete, and that is causing this problem.

The ToDos finder should be updated to exclude projects pending deletion. Then we should figure out why projects aren't being deleted.

The nil is caused by the project model's default scope, something we are trying to also fix in: https://gitlab.com/gitlab-org/gitlab-ce/issues/15440

Milestone changed to %8.8

mentioned in issue #17893 (closed)

The projects not being deleted has been created as a new issue: https://gitlab.com/gitlab-org/gitlab-ce/issues/17893

Umm... even if those projects are deleted in the end, before that happening, it would still cause issues. I think this is also a proof that default_scope with where which could filter out results would be tricky and error-prone. It's probably not just Todo, Issue and so on so forth could have the same problem.

I guess there's no easy way to fix this. All I can think of is stop using default_scope that way, and yet pending_delete itself is very tricky as well. Fake delete is hard.

Reassigned to @twk3

@godfat Right, I thought that the patch to remove default_scope was already in 8.8, but !4104 (closed) is still under review.

mentioned in merge request !4300 (merged)

Added regression label

mentioned in issue gitlab-com/support-forum#678 (closed)

Status changed to closed by merge request !4300 (merged)

mentioned in commit 70499125

mentioned in merge request !4663 (merged)

Mentioned in commit pfjason/gitlab-ce@a834be61

Mentioned in commit pfjason/gitlab-ce@70499125