Fix N+1 Gitaly calls in /api/v4/projects/:id/issues
This is a follow-up from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/31938.
In GitLab 9.0,
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/9661 removed the
subscribed
flag from the API when the user requested a list of issues
or merge requests since calculating this value triggers extensive
Markdown processing.
In GitLab 12.0 via a4fbf39e, we accidentally reintroduced this
performance regression by changing IssueBasic
to Issue
in
entities.rb
. This showed up as a Gitaly N+1 issue since the Markdown
processing would attempt to extract a commit if it detected a regex
that matched a commit.
We restore the prior behavior by once again removing the subscribed
flag
for the bulk list of issues and merge requests and add a test to ensure
they aren't reintroduced.
Relates to https://gitlab.com/gitlab-org/gitlab-ce/issues/66202