The motivation for this change is performance. The forums UI code gets
the list of users for each role and renders the staff label based on
those lists. The list for the staff role is expensive to compute because
there is no index on the is_staff attribute, and we cannot create one
because the User model is built into django.
Users with is_staff=True are still assigned the Moderator role upon
enrolling in a course, so this change will have no practical effect
except that a user who is granted staff privileges after enrolling in a
course will have to be made a Moderator in order for their posts to be
labeled.
Additionally, the UI did not use the list of users with the Student
role, so that list has been removed as well.
* make `user_status` more intelligent
* remove some logic from the templates
* rename `parse_error_msg` to `parsed_error_msg`
* fix up and add more tests
LMS-1387
Avoid recomputing course module information for every thread, which
should dramatically improve the performance of high-percentile latency
queries.
JIRA: FOR-250
The _DISCUSSIONINFO global was originally used as a cache, but has since
lost that capability and is therefore just harmful. This is a precursor
to more refactoring that will improve the performance of the forums and
may itself provide some performance improvement because it separates the
computation done by two functions that each previously computed the
entirety of _DISCUSSIONINFO.
CommentClientError now has sane subclasses that are meaningfully
distinct, and each subclass is handled appropriately. Errors raised by
the requests library are no longer handled by turning them into
CommentClientErrors, since there is no meaningful handling we can do,
and this way we will get more visibility into why errors are occurring.
Also, HTTP status codes from the comments service indicating client
error are correctly passed through to the client.
Previously, whenever a XModule was created from a XDescriptor, we
created another level of nesting of FieldData objects. This change
prevents that nesting.
[TKTS-393]
