[2.1.x] Fixed #29400 -- Fixed crash in custom template filters that use decorated functions.

Regression in 620e9dd31a2146d70de740f96a8cb9a6db054fc7.

Backport of a8d12bc28069d56e0306770ab9c73738293663f7 from master

2 files changed, 13 insertions, 0 deletions

diff --git a/tests/template_tests/templatetags/custom.py b/tests/template_tests/templatetags/custom.py
index 2e2ccf3782..45acd9655e 100644
--- a/tests/template_tests/templatetags/custom.py
+++ b/tests/template_tests/templatetags/custom.py
@@ -3,6 +3,7 @@ import operator
 from django import template
 from django.template.defaultfilters import stringfilter
 from django.utils.html import escape, format_html
+from django.utils.safestring import mark_safe
 
 register = template.Library()
 
@@ -14,6 +15,13 @@ def trim(value, num):
 
 
 @register.filter
+@mark_safe
+def make_data_div(value):
+    """A filter that uses a decorator (@mark_safe)."""
+    return '<div data-name="%s"></div>' % value
+
+
+@register.filter
 def noop(value, param=None):
     """A noop filter that always return its first argument and does nothing with
     its second (optional) one.
diff --git a/tests/template_tests/test_custom.py b/tests/template_tests/test_custom.py
index b37b5f8f1e..dbc5bc267d 100644
--- a/tests/template_tests/test_custom.py
+++ b/tests/template_tests/test_custom.py
@@ -25,6 +25,11 @@ class CustomFilterTests(SimpleTestCase):
             "abcde"
         )
 
+    def test_decorated_filter(self):
+        engine = Engine(libraries=LIBRARIES)
+        t = engine.from_string('{% load custom %}{{ name|make_data_div }}')
+        self.assertEqual(t.render(Context({'name': 'foo'})), '<div data-name="foo"></div>')
+
 
 class TagTestCase(SimpleTestCase):