reverse() breaks on URLs which include a ~ character

[mxheyeck@…]

Testing on my local machine through Apache, so the root URL is at:

​http://localhost/~mxheyeck/sicariid/

Calling reverse on one of my views inside views.py, e.g.:

s = reverse(locate_task_enter, args=(task_id,))

Breaks with the cryptic message:

"a float is required"

A little examination reveals what's going on. Break is at line 391 of urlresolvers.py.

candidate = (prefix_norm + result) % dict(zip(prefix_args + params, unicode_args))

prefix_norm is:

u'/%7Emxheyeck/sicariid/'

So line 391 is equivalent to:

u'/%7Emxheyeck/sicariid/locate_task_enter/%(task_id)s/' % {u'task_id': u'419'}

Where '%7E' is both a urlencoded tilde and, unfortunately, an upper-case floating-point exponential. So, boom.

I attach the local vars from the break at 391.

val		419L
pattern		'locate_task_enter/(?P<task_id>\\d+)/$'
self		<RegexURLResolver 'sitespecific.urls' (None:None) ^/>
args		(419L,)
_prefix		u'/~mxheyeck/sicariid/'
possibility	[(u'locate_task_enter/%(task_id)s/', [u'task_id'])]
unicode_args	[u'419']
possibilities	[([(u'locate_task_enter/%(task_id)s/', [u'task_id'])],  'locate_task_enter/(?P<task_id>\\d+)/$',  {})]
lookup_view	<function locate_task_enter at 0x1065f8668>
prefix_norm	u'/%7Emxheyeck/sicariid/'
prefix_args	[]
params		[u'task_id']
result		u'locate_task_enter/%(task_id)s/'
defaults	{}
kwargs		{}

[Baptiste Mispelon]

This seems to have been overlooked when fixing #18210.

The fix should be similar: escape any % present in the prefix.

Note that a temporary workaround is to used named arguments (kwargs) for reverse.

[Baptiste Mispelon <bmispelon@…>]

In 4fa7f3cdd9bcf50ec4c7f64a31c1dfc02c375f46:

Fix #20022: Correctly handle prefixes with url-unsafe characters in reverse().

[Jacob Kaplan-Moss <jacob@…>]

In e4d9f8aed11e964885cd77f8abd01ba0dfa4aa13:

Merge pull request #900 from bmispelon/ticket-20022

Fix #20022: Correctly handle prefixes with url-unsafe characters in reverse()

[Florian Apolloner <florian@…>]

In 1059da8de675442e84381d6366c0be254681753e:

Merge pull request #900 from bmispelon/ticket-20022

Fix #20022: Correctly handle prefixes with url-unsafe characters in reverse()