Fixed #17492 -- Allow reversal of named backreferences. Thanks nate_b

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17336 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/utils/regex_helper.py

@@ -134,18 +134,28 @@ def normalize(pattern):
                         raise ValueError("Non-reversible reg-exp portion: '(?%s'" % ch)
                     else:
                         ch, escaped = pattern_iter.next()
-                        if ch != '<':
+                        if ch not in ('<', '='):
                             raise ValueError("Non-reversible reg-exp portion: '(?P%s'" % ch)
                         # We are in a named capturing group. Extra the name and
                         # then skip to the end.
+                        if ch == '<':
+                            terminal_char = '>'
+                        # We are in a named backreference.
+                        else:
+                            terminal_char = ')'
                         name = []
                         ch, escaped = pattern_iter.next()
-                        while ch != '>':
+                        while ch != terminal_char:
                             name.append(ch)
                             ch, escaped = pattern_iter.next()
                         param = ''.join(name)
+                        # Named backreferences have already consumed the
+                        # parenthesis.
+                        if terminal_char != ')':
                             result.append(Group(((u"%%(%s)s" % param), param)))
                             walk_to_end(ch, pattern_iter)
+                        else:
+                            result.append(Group(((u"%%(%s)s" % param), None)))
             elif ch in "*?+{":
                 # Quanitifers affect the previous item in the result list.
                 count, ch = get_quantifier(ch, pattern_iter)

tests/regressiontests/urlpatterns_reverse/tests.py

@@ -76,6 +76,8 @@ test_data = (
     ('people', NoReverseMatch, [], {'name': 'name with spaces'}),
     ('people2', '/people/name/', [], {}),
     ('people2a', '/people/name/fred/', ['fred'], {}),
+    ('people_backref', '/people/nate-nate/', ['nate'], {}),
+    ('people_backref', '/people/nate-nate/', [], {'name': 'nate'}),
     ('optional', '/optional/fred/', [], {'name': 'fred'}),
     ('optional', '/optional/fred/', ['fred'], {}),
     ('hardcoded', '/hardcoded/', [], {}),

tests/regressiontests/urlpatterns_reverse/urls.py

@@ -22,6 +22,7 @@ urlpatterns = patterns('',
     url(r'^people/(?P<name>\w+)/$', empty_view, name="people"),
     url(r'^people/(?:name/)', empty_view, name="people2"),
     url(r'^people/(?:name/(\w+)/)?', empty_view, name="people2a"),
+    url(r'^people/(?P<name>\w+)-(?P=name)/$', empty_view, name="people_backref"),
     url(r'^optional/(?P<name>.*)/(?:.+/)?', empty_view, name="optional"),
     url(r'^hardcoded/$', empty_view, name="hardcoded"),
     url(r'^hardcoded/doc\.pdf$', empty_view, name="hardcoded2"),
@@ -65,7 +66,4 @@ urlpatterns = patterns('',
     (r'defaults_view2/(?P<arg1>\d+)/', 'defaults_view', {'arg2': 2}, 'defaults'),
 
     url('^includes/', include(other_patterns)),
-
 )
-
-

tests/regressiontests/utils/regex_helper.py

@@ -0,0 +1,48 @@
+from django.utils import regex_helper
+from django.utils import unittest
+
+
+class NormalizeTests(unittest.TestCase):
+    def test_empty(self):
+        pattern = r""
+        expected = [(u'', [])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)
+
+    def test_escape(self):
+        pattern = r"\\\^\$\.\|\?\*\+\(\)\["
+        expected = [(u'\\^$.|?*+()[', [])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)
+
+    def test_group_positional(self):
+        pattern = r"(.*)-(.+)"
+        expected = [(u'%(_0)s-%(_1)s', ['_0', '_1'])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)
+
+    def test_group_ignored(self):
+        pattern = r"(?i)(?L)(?m)(?s)(?u)(?#)"
+        expected = [(u'', [])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)
+
+    def test_group_noncapturing(self):
+        pattern = r"(?:non-capturing)"
+        expected = [(u'non-capturing', [])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)
+
+    def test_group_named(self):
+        pattern = r"(?P<first_group_name>.*)-(?P<second_group_name>.*)"
+        expected = [(u'%(first_group_name)s-%(second_group_name)s',
+                    ['first_group_name', 'second_group_name'])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)
+
+    def test_group_backreference(self):
+        pattern = r"(?P<first_group_name>.*)-(?P=first_group_name)"
+        expected = [(u'%(first_group_name)s-%(first_group_name)s',
+                    ['first_group_name'])]
+        result = regex_helper.normalize(pattern)
+        self.assertEqual(result, expected)

tests/regressiontests/utils/tests.py

@@ -25,3 +25,4 @@ from .ipv6 import TestUtilsIPv6
 from .timezone import TimezoneTests
 from .crypto import TestUtilsCryptoPBKDF2
 from .archive import TestZip, TestTar, TestGzipTar, TestBzip2Tar
+from .regex_helper import NormalizeTests