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
29415	custom url converters are not picked up on reverse when part of included patterns	Xaroth	nobody	"Under normal circumstances, url converters `to_url` methods are called when reversing a url, however, this behavior is inconsistent when used with included sub-patterns

To demonstrate:
{{{
from django.urls import path, include, register_converter
from django.urls.converters import StringConverter


class ReverseConverter(StringConverter):
    def to_python(self, value):
        """"""More complex use cases are possible, but this simple case of reversing the string already shows it in effect""""""
        return value[::-1]

    def to_url(self, obj):
        """"""More complex use cases are possible, but this simple case of reversing the string already shows it in effect""""""
        return obj[::-1]

register_converter(ReverseConverter, 'rstr')


def noop(request):  # A noop since we are merely testing reverse()
    pass


# Patterns in here will 
included_patterns = [
    path('', noop, name='fail-case-1'),
    path('<rstr:itemb>', noop, name='fail-case-2'),
]

direct_patterns = [
    path('<rstr:item>', noop, name='success-case-1'),
    path('<rstr:item>/<rstr:itemb>', noop, name='success-case-2'),
]

urlpatterns = [
    path('<rstr:item>/', include(included_patterns)),
    path('', include(direct_patterns)),
    path('<rstr:item>', noop, name='success-case-3'),
]
}}}

When running the following test, both patterns -should- return the same URL, however, they do not:

{{{
In [1]: from django.urls import reverse

In [2]: reverse('success-case-1', kwargs={'item': 'abc123'})  # Expected: '/321cba'
Out[2]: '/321cba'

In [3]: reverse('success-case-2', kwargs={'item': 'abc123', 'itemb': 'xyz789'})  # Expected: '/321cba/987zyx'
Out[3]: '/321cba/987zyx'

In [4]: reverse('success-case-3', kwargs={'item': 'abc123'})  # Expected: '/321cba'
Out[4]: '/321cba'

In [5]: reverse('fail-case-1', kwargs={'item': 'abc123'})  # Expected: '/321cba/'
Out[5]: '/abc123/'

In [6]: reverse('fail-case-2', kwargs={'item': 'abc123', 'itemb': 'xyz789'})  # Expected: '/321cba/987zyx'
Out[6]: '/abc123/987zyx'
}}}
Note that at the last case, `item` is not reversed, where `itemb` is.

The main culprit (I think) is that when populating the URLResolver's reverse_dict, included sub-resolvers are not updated with the converters of the resolver that includes them, as such, they skip the converters for the base resolver when reversing the URL.

I have confirmed this inconsistency in versions 2.0 through 2.0.5, 2.1a1 as well as master (@9f6188b).
"	Bug	closed	Core (URLs)	dev	Normal	fixed			Accepted	1	0	0	0	0	0