I've done a full grep on Issue.objects, Project.objects and get_object_or_404
equivelents, and applying some common sense. The goal: avoid having
confusing/half-broken pages in the UI.
On index-usage: I've decided not to update the indexes. The assumption is:
`is_deleted` items will be a tiny minority of items in general, making the
cost/benefit analysis not turn out favorably (just scanning them out as a final
step is more efficient). Also: sqlite is able to use the correct index without
adding a special one, proof:
```
EXPLAIN QUERY PLAN SELECT [..] WHERE ("issues_issue"."project_id" = 1 AND "issues_issue"."is_muted" = (0) AND "issues_issue"."is_resolved" = (0)) ORDER BY "issues_issue"."last_seen" DESC LIMIT 250;
QUERY PLAN
`--SEARCH issues_issue USING INDEX issue_list_open (project_id=? AND is_resolved=? AND is_muted=?)
EXPLAIN QUERY PLAN SELECT [..] WHERE ("issues_issue"."project_id" = 1 AND "issues_issue"."is_muted" = (0) AND "issues_issue"."is_resolved" = (0) AND "issues_issue"."is_deleted" = 0) ORDER BY "issues_issue"."last_seen" DESC LIMIT 250;
QUERY PLAN
`--SEARCH issues_issue USING INDEX issue_list_open (project_id=? AND is_resolved=? AND is_muted=?)
```
See #139 for the 0/1 notation in the above.
(Project-indexes: not an issue, the scale is "below relevance for indexes")
Implement delete functionality with confirmation modals for projects.
cherry picked (by Klaas) from commit 6764fbf343fb; but:
* projects only
* `delete_deferred`
* flake8
See #84 for the original PR
For now, sticking to "how it actually works" is more important than "what we
might need in the future". We don't have an admin-group with actually handed
out perms yet, and we do have the recommendation to create a superuser in the
installation docs. So let's just explicity check for that.
(I found these checks while working on actual breakage in the previous commit)
