Fixed #28694 -- Made django.utils.text.slugify() strip dashes and underscores.

django/utils/text.py

@@ -396,15 +396,15 @@ def slugify(value, allow_unicode=False):
     Convert to ASCII if 'allow_unicode' is False. Convert spaces or repeated
     dashes to single dashes. Remove characters that aren't alphanumerics,
     underscores, or hyphens. Convert to lowercase. Also strip leading and
-    trailing whitespace.
+    trailing whitespace, dashes, and underscores.
     """
     value = str(value)
     if allow_unicode:
         value = unicodedata.normalize('NFKC', value)
     else:
         value = unicodedata.normalize('NFKD', value).encode('ascii', 'ignore').decode('ascii')
-    value = re.sub(r'[^\w\s-]', '', value.lower()).strip()
+    value = re.sub(r'[^\w\s-]', '', value.lower())
-    return re.sub(r'[-\s]+', '-', value)
+    return re.sub(r'[-\s]+', '-', value).strip('-_')
 
 
 def camel_case_to_spaces(value):

docs/ref/utils.txt

@@ -853,8 +853,8 @@ appropriate entities.
     #. Converting to lowercase.
     #. Removing characters that aren't alphanumerics, underscores, hyphens, or
        whitespace.
-    #. Removing leading and trailing whitespace.
     #. Replacing any whitespace or repeated dashes with single dashes.
+    #. Removing leading and trailing whitespace, dashes, and underscores.
 
     For example::
 
@@ -867,6 +867,11 @@ appropriate entities.
         >>> slugify('你好 World', allow_unicode=True)
         '你好-world'
 
+    .. versionchanged:: 3.2
+
+        In older versions, leading and trailing dashes and underscores are not
+        removed.
+
 .. _time-zone-selection-functions:
 
 ``django.utils.timezone``

docs/releases/3.2.txt

@@ -280,6 +280,9 @@ Miscellaneous
 * :attr:`.ModelAdmin.prepopulated_fields` no longer strips English stop words,
   such as ``'a'`` or ``'an'``.
 
+* :func:`~django.utils.text.slugify` now removes leading and trailing dashes
+  and underscores.
+
 .. _deprecated-features-3.2:
 
 Features deprecated in 3.2

tests/utils_tests/test_text.py

@@ -195,6 +195,10 @@ class TestUtilsText(SimpleTestCase):
             (' multiple---dash and  space ', 'multiple-dash-and-space', False),
             ('\t whitespace-in-value \n', 'whitespace-in-value', False),
             ('underscore_in-value', 'underscore_in-value', False),
+            ('__strip__underscore-value___', 'strip__underscore-value', False),
+            ('--strip-dash-value---', 'strip-dash-value', False),
+            ('__strip-mixed-value---', 'strip-mixed-value', False),
+            ('_ -strip-mixed-value _-', 'strip-mixed-value', False),
             ('spam & ıçüş', 'spam-ıçüş', True),
             ('foo ıç bar', 'foo-ıç-bar', True),
             ('    foo ıç bar', 'foo-ıç-bar', True),