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
35229	Prevent repeated checks of custom error handler URLs	Adam Johnson	Adam Johnson	"In #29642 I added a system check for custom error handler URLs.

I looked at a profile for running the system checks on a project and found this check function ran hundreds of times rather than once, totalling 1/4 of the time to run checks. The multiple runs occur because the check is defined on `URLResolver`, of which exist in a tree structure. Moving the check from `URLResolver` to a function in `django.core.checks.urls` ensures it runs only once.

In the profiled project with 279 URLs, this takes the checks from ~24ms to ~21ms, a ~13% saving."	Cleanup/optimization	closed	Core (System checks)	dev	Normal	fixed			Ready for checkin	1	0	0	0	0	0