commit.diff(branch, create_patch=True) gets "+" and "-" backwards

[lhannest]

When I do this:

>>> import git
>>> r = git.Repo('.')
>>> from pprint import pprint
>>> pprint(r.active_branch.commit.diff('master', create_patch=True)[0].diff.decode('utf-8').split('\n'))

Then I see the same first file as when I do git diff master in the terminal. But, it gets the "+" and "-" backwards. In python I see lines such as:

...
'-import static org.mockito.Matchers.anyLong;',
'-import static org.mockito.Matchers.anyString;',
'-import static org.mockito.Mockito.times;',
...

But this is a file I've added in the active branch that isn't in the master! In the terminal when I do git diff master I see:

...
+import static org.mockito.Matchers.anyLong;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Mockito.times;
...

On the other hand, when I use pprint(r.git.diff('master').split('\n')) then I get the right result:

...
'+import static org.mockito.Matchers.anyLong;',
'+import static org.mockito.Matchers.anyString;',
'+import static org.mockito.Mockito.times;',
...

[lhannest]

I guess this is related to #852 (comment)

If I add R=True to the line:

pprint(r.active_branch.commit.diff('master', create_patch=True, R=True)[0].diff.decode('utf-8').split('\n')) 

Then I seem to get the right results. But this still seems like a bug! Will this be fixed someday?

I'm worried that if I add R=True now, then someday when this is fixed my program will silently stop working correctly.

[Byron]

Apparently this was believed to be fixed here: 14d7034. Maybe in your particular case it still is inverted? Or is the version you are using not the most recent one?

Thanks to a particularly occluded API GitPython can be really confusing, making it hard to understand what's diffed against what. Thus I would not be surprised if there are more issues slumbering there or the fix above isn't correct in all cases.

If you figure it out a PR would be welcome.