From 2326dedde81c59950d2b1e0653a837e1d7019acd Mon Sep 17 00:00:00 2001
From: Florian Apolloner <florian@apolloner.eu>
Date: Fri, 6 Sep 2013 19:16:06 +0200
Subject: [PATCH] Fixed #20812 -- Error out if __unicode__/__str__ doesn't
 return a text type.

---
 django/utils/encoding.py           | 17 ++++++++---------
 tests/utils_tests/test_encoding.py | 17 ++++++++++++++++-
 2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/django/utils/encoding.py b/django/utils/encoding.py
index 667c3def45..a7239f4b0f 100644
--- a/django/utils/encoding.py
+++ b/django/utils/encoding.py
@@ -67,16 +67,15 @@ def force_text(s, encoding='utf-8', strings_only=False, errors='strict'):
         return s
     try:
         if not isinstance(s, six.string_types):
-            if hasattr(s, '__unicode__'):
-                s = s.__unicode__()
-            else:
-                if six.PY3:
-                    if isinstance(s, bytes):
-                        s = six.text_type(s, encoding, errors)
-                    else:
-                        s = six.text_type(s)
+            if six.PY3:
+                if isinstance(s, bytes):
+                    s = six.text_type(s, encoding, errors)
                 else:
-                    s = six.text_type(bytes(s), encoding, errors)
+                    s = six.text_type(s)
+            elif hasattr(s, '__unicode__'):
+                s = six.text_type(s)
+            else:
+                s = six.text_type(bytes(s), encoding, errors)
         else:
             # Note: We use .decode() here, instead of six.text_type(s, encoding,
             # errors), so that if s is a SafeBytes, it ends up being a
diff --git a/tests/utils_tests/test_encoding.py b/tests/utils_tests/test_encoding.py
index 5730eca6d5..81a4c4f5da 100644
--- a/tests/utils_tests/test_encoding.py
+++ b/tests/utils_tests/test_encoding.py
@@ -4,10 +4,25 @@ from __future__ import unicode_literals
 import unittest
 import datetime
 
-from django.utils.encoding import force_bytes, filepath_to_uri
+from django.utils import six
+from django.utils.encoding import force_bytes, force_text, filepath_to_uri
 
 
 class TestEncodingUtils(unittest.TestCase):
+    def test_force_text_exception(self):
+        """
+        Check that broken __unicode__/__str__ actually raises an error.
+        """
+        class MyString(object):
+            def __str__(self):
+                return b'\xc3\xb6\xc3\xa4\xc3\xbc'
+
+            __unicode__ = __str__
+
+        # str(s) raises a TypeError on python 3 if the result is not a text type.
+        # python 2 fails when it tries converting from str to unicode (via ASCII).
+        exception = TypeError if six.PY3 else UnicodeError
+        self.assertRaises(exception, force_text, MyString())
 
     def test_force_bytes_exception(self):
         """