Fixed #21574 -- Handle bytes consistently in utils.text.normalize_newlines.

All input is now coerced to text before being normalized.
This changes nothing under Python 2 but it allows bytes
to be passed to the function without a TypeError under Python3
(bytes are assumed to be utf-8 encoded text).

Thanks to trac user vajrasky for the report.

django/utils/text.py

@@ -250,7 +250,9 @@ get_text_list = allow_lazy(get_text_list, six.text_type)
 
 
 def normalize_newlines(text):
-    return force_text(re_newlines.sub('\n', text))
+    """Normalizes CRLF and CR newlines to just LF."""
+    text = force_text(text)
+    return re_newlines.sub('\n', text)
 normalize_newlines = allow_lazy(normalize_newlines, six.text_type)
 
 

tests/utils_tests/test_text.py

@@ -2,7 +2,7 @@
 from __future__ import unicode_literals
 
 from django.test import SimpleTestCase
-from django.utils import text
+from django.utils import six, text
 
 
 class TestUtilsText(SimpleTestCase):
@@ -114,6 +114,12 @@ class TestUtilsText(SimpleTestCase):
         self.assertEqual(text.normalize_newlines("abcdefghi"), "abcdefghi")
         self.assertEqual(text.normalize_newlines(""), "")
 
+    def test_normalize_newlines_bytes(self):
+        """normalize_newlines should be able to handle bytes too"""
+        normalized = text.normalize_newlines(b"abc\ndef\rghi\r\n")
+        self.assertEqual(normalized, "abc\ndef\nghi\n")
+        self.assertIsInstance(normalized, six.text_type)
+
     def test_slugify(self):
         items = (
             ('Hello, World!', 'hello-world'),