id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
30171	Fix DatabaseError threading error during servers tests	Jon Dufresne	nobody	"When running tests with Python warnings enabled, `tests.servers.tests.LiveServerPort` produces a warning of the form:

{{{
Exception in thread Thread-1:
Traceback (most recent call last):
  File ""/usr/lib64/python3.7/threading.py"", line 917, in _bootstrap_inner
    self.run()
  File ""django/test/testcases.py"", line 1399, in run
    connections.close_all()
  File ""django/db/utils.py"", line 224, in close_all
    connection.close()
  File ""django/db/backends/sqlite3/base.py"", line 244, in close
    self.validate_thread_sharing()
  File ""django/db/backends/base/base.py"", line 531, in validate_thread_sharing
    % (self.alias, self._thread_ident, _thread.get_ident())
django.db.utils.DatabaseError: DatabaseWrapper objects created in a thread can only be used in that same thread. The object with alias 'default' was created in thread id 139685002331648 and this is thread id 139684747486976.
}}}

This occurs because multiple classes set `DatabaseWrapper.allow_thread_sharing` to false upon test tear down. The base test class and the temporarily created test class. In other words, nesting the setup/teardown of `DatabaseWrapper.allow_thread_sharing` isn't always handled cleanly.
"	Cleanup/optimization	closed	Database layer (models, ORM)	2.2	Normal	fixed			Ready for checkin	1	0	0	0	0	0