py3: ensure that we don't concat bytes and str and the end result is bytes Here obj.__module__ and obj.__name__ are str. Either we can convert them to bytes or use an r'' and convert back to bytes when concat is done. I preferred the later one since we are encoding only once here.

py3: make sure we return strings from __str__ and __repr__ On Python 3: >>> class abc: ... def __repr__(self): ... return b'abc' ... >>> abc() Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: __repr__ returned non-string (type bytes) >>> class abc: ... def __str__(self): ... return b'abc' ... >>> str(abc()) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: __str__ returned non-string (type bytes) So the __str__ and __repr__ must return strings.

py3: replace None with -1 to sort an integer array In Python 2: >>> ls = [4, 2, None] >>> sorted(ls) [None, 2, 4] In Python 3: >>> ls = [4, 2, None] >>> sorted(ls) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: unorderable types: NoneType() < int() Therefore we replaced None with -1, and the safe part is that, None and -1 are only the keys which are used for sorting so we don't need to convert the -1's back to None.

py3: pass str in os.sysconf() os.sysconf() doesn't accepts bytes on Python 3. Adding r'' will make sure b'' is not added here.

context: move dirty() to committablectx This is a pedantic move. It should be an error if dirty() is called on a read-only context. Based on Mads Kiilerix's and my work at the sprint.

committablectx: extra is already normalized by committablectx.__init__ Avoid doing the same work again. Based on work done by Mads Kiilerix.