Merge 8864-safe_str-unicode: safe_str encodes unicode

Author: markrwilliams
Reviewer: Julian
Fixes: twisted#8864

twisted.python.reflect.safe_str encodes unicode as ascii with backslashreplace error handling on Python 2.

src/twisted/python/reflect.py

@@ -436,6 +436,13 @@ def safe_str(o):
             return o.decode('utf-8')
         except:
             pass
+    if not _PY3:
+        # On Python 2, attempt to encode a unicode representation
+        # first.
+        try:
+            return unicode(o).encode('ascii', 'backslashreplace')
+        except:
+            pass
     try:
         return str(o)
     except:

src/twisted/test/test_log.py

@@ -390,20 +390,19 @@ def testMultipleString(self):
 
     def test_singleUnicode(self):
         """
-        L{log.LogPublisher.msg} does not accept non-ASCII Unicode on Python 2,
-        logging an error instead.
+        L{log.LogPublisher.msg} encodes Unicode as ``ascii`` with
+        ``backslashreplace`` error handling on Python 2.
 
-        On Python 3, where Unicode is default message type, the message is
-        logged normally.
+        On Python 3, where Unicode is default message type, the
+        message is logged normally.
         """
         message = u"Hello, \N{VULGAR FRACTION ONE HALF} world."
         self.lp.msg(message)
         self.assertEqual(len(self.out), 1)
         if _PY3:
             self.assertIn(message, self.out[0])
         else:
-            self.assertIn('with str error', self.out[0])
-            self.assertIn('UnicodeEncodeError', self.out[0])
+            self.assertIn(r"Hello, \xbd world", self.out[0])
 
 
 

src/twisted/test/test_reflect.py

@@ -630,6 +630,20 @@ class X(BTBase):
         self.assertIn("RuntimeError: str!", xStr)
 
 
+    def test_unicode(self):
+        """
+        A unicode string is encoded to ``ascii`` with
+        ``backslashreplace`` error handling on Python 2.
+        """
+        unicodeString = u'\N{DOUBLE EXCLAMATION MARK} !!'
+        safe = reflect.safe_str(unicodeString)
+        self.assertEqual(safe, b'\u203c !!')
+
+    if _PY3:
+        test_unicode.skip = (
+            "Skip Python 2 specific test for unicode encoding")
+
+
 
 class FilenameToModuleTests(TestCase):
     """

src/twisted/topfiles/8864.bugfix

@@ -0,0 +1 @@
+twisted.python.reflect.safe_str encodes unicode as ascii with backslashreplace error handling on Python 2.