Merge pull request #59 from rouge8/gh-5

Don't crash when printing tracebacks under IPython on Python 2

transaction/_compat.py

@@ -36,7 +36,13 @@ def native_(s, encoding='latin-1', errors='strict'): #pragma NO COVER
 if PY3: #pragma NO COVER
     from io import StringIO
 else:
-    from io import BytesIO as StringIO
+    from io import BytesIO
+    # Prevent crashes in IPython when writing tracebacks if a commit fails
+    # ref: https://github.com/ipython/ipython/issues/9126#issuecomment-174966638
+    class StringIO(BytesIO):
+        def write(self, s):
+            s = native_(s, encoding='utf-8')
+            super(StringIO, self).write(s)
 
 if PY3: #pragma NO COVER
     from collections import MutableMapping

transaction/tests/test__transaction.py

@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 ##############################################################################
 #
 # Copyright (c) 2001, 2002, 2005 Zope Foundation and Contributors.
@@ -1649,6 +1650,18 @@ def third():
         transaction.abort() # should do nothing
         self.assertEqual(list(dm.keys()), ['a'])
 
+    def test_gh5(self):
+        from transaction import _transaction
+        from transaction._compat import native_
+
+        buffer = _transaction._makeTracebackBuffer()
+
+        s = u'ąčę'
+        buffer.write(s)
+
+        buffer.seek(0)
+        self.assertEqual(buffer.read(), native_(s, 'utf-8'))
+
 class Resource(object):
     _b = _c = _v = _f = _a = _x = _after = False
     def __init__(self, key, error=None):