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
31254	"""populate() isn't reentrant"" masks underlying error"	TK-23	nobody	"I'm new to reporting bugs, but have struggled with this one enough that I thought I would formally document an issue we've seen.

In django/django/apps/registry.py (https://github.com/django/django/blob/20ba3ce4ac8e8438070568ffba76f7d8d4986a53/django/apps/registry.py#L83)  there is a line of code that can raise an error when running simple commands like {{{python manage.py runserver}}}:

{{{
if self.loading:
                # Prevent reentrant calls to avoid running AppConfig.ready()
                # methods twice.
                raise RuntimeError(""populate() isn't reentrant"")
}}}

The problem is that this generic error can mask the true reason why django will not start up (I've seen the true reason be something like a problem with a version of a Python package needing to be updated, or an import of a module that does not exist elsewhere in the code). Based on a stackoverflow response (https://stackoverflow.com/questions/27093746/django-stops-working-with-runtimeerror-populate-isnt-reentrant) I've learned to comment out {{{raise RuntimeError(""populate() isn't reentrant"")}}} and replace it with {{{self.app_configs={} }}}

This way the true error will be exposed when starting up django. I do not know the best way to handle this but before I found this stackoverflow post, we lost a lot of time trying to debug issues. Even knowing this workaround it is a hassle to adjust the django code to see the true error.

I can provide a link to our opensource project with a branch set up to replicate the error if that is helpful.
"	Bug	closed	Core (Other)	2.2	Normal	needsinfo		Carlton Gibson	Unreviewed	0	0	0	0	0	0