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
9038	url tag not working with reverse in 1.0 as it previously did	marystern@…	Malcolm Tredinnick	"I was getting a TemplateSyntaxError caused by a NoReverseMatch error with DJango 1.0 for code which previously worked.

{{{
Exception Type:  	TemplateSyntaxError
Exception Value: 	

Caught an exception while rendering: Reverse for 'x.x_edit' with arguments '(7,)' and keyword arguments '{}' not found.
Original Traceback (most recent call last):
  File ""/usr/local/lib/python2.5/site-packages/django/template/debug.py"", line 71, in render_node
    result = node.render(context)
  File ""/usr/local/lib/python2.5/site-packages/django/template/defaulttags.py"", line 378, in render
    args=args, kwargs=kwargs)
  File ""/usr/local/lib/python2.5/site-packages/django/core/urlresolvers.py"", line 252, in reverse
    *args, **kwargs)))
  File ""/usr/local/lib/python2.5/site-packages/django/core/urlresolvers.py"", line 241, in reverse
    ""arguments '%s' not found."" % (lookup_view, args, kwargs))
NoReverseMatch: Reverse for 'x.x_edit' with arguments '(7,)' and keyword arguments '{}' not found.

Exception Location: 	/usr/local/lib/python2.5/site-packages/django/template/debug.py in render_node, line 81

}}}

I eventually tracked it down to this:

I was using a url template tag to match the name 'edit' (see below). The pattern was the same as a preceding pattern which matched the same prefix with an optional number after it. This first url pattern had no name (I'd originally found I needed the 2 patterns because the first pattern had 2 slashes at the end and didn't match the one slash I wanted).

{{{
    url(r'^x/edit/(?P<x_id>[0-9]*)/$', x_edit,),
    url(r'^x/edit/$',                  x_edit, name='x_edit'),
}}}

The snippet of template code was:

{{{
<form action=""{% url x_edit x.id %}/"" method=""post"" name=""my_form""> 
}}}

This used to work (presumably by failing the named match and somehow matching the un-named one?).

However, in 1.0 it stopped working (I guess because the url resolver has been re-worked).

I found (after much debugging), that I could fix the problem by adding another name for the 1st pattern, eg

{{{
    url(r'^x/edit/(?P<x_id>[0-9]*)/$', x_edit, name='x_edit_id'),
    url(r'^x/edit/$',                  x_edit, name='x_edit'),
}}}

and changing my template to use it:
{{{
 <form action=""{% url x_edit_id x.id %}/"" method=""post"" name=""my_form""> 
}}}

This took quite a while for me to find, and I'd like peole to not have to do the same as I have in migrating from older code to 1.0!

Can you maybe confirm the above and document this somewhere sensible for people who are migrating from 0.96+ to 1.0 (I think this was probably a backwards-incompatible change)?

Thanks!
Mary."		closed	Core (Other)	1.0		fixed	url, reverse		Accepted	0	0	0	0	0	0