repo.index.diff( head ) show new file as deleted

[barry-scott]

My goal is to use GitPython to get the same information that git status will return.

I'm using the examples from the Tutorial.

I have a test repo with the following status:

$ git status
On branch master
Your branch is up-to-date with 'origin/master'.
Changes to be committed:
(use "git reset HEAD ..." to unstage)

    new file:   World.txt

Untracked files:
(use "git add ..." to include in what will be committed)

I run this python using GitPython 2.0.2:

r = git.Repo( '/home/barry/wc/git/testrepo-a' )
print( 'Diff HEAD' )
for diff in r.index.diff( r.head.commit ):
for name in dir(diff):
if name[0] not in '_N':
print( ' %s: %r' % (name, getattr( diff, name )) )

And see this output:
Diff HEAD
a_blob: <git.Blob "df6ee5136ef5fd4a4ebdfef1ffce74bd0a71b514">
a_mode: 33188
a_path: 'World.txt'
b_blob: None
b_mode: 0
b_path: 'World.txt'
deleted_file: True
diff: ''
new_file: False
rename_from: None
rename_to: None
renamed: False

It seems that the diff in backwards: Iwould expect to see new_file: True. not deleted_file: True.

Where as a repo.index.diff( None ) seems to get old vs. new right.

[barry-scott]

I think I understand why this is happening.

 repo.index.diff( HEAD ) is index(new) vs. HEAD(old)

but

repo.index.diff( None ) is index(old) vs. WorkingCopy(new)

Hence the meaning of new_file/deleted_file will reverse.

Might be worth pointing this out in the docs.

[Byron]

Thanks for letting me know ! I did just try it myself, and could only come to the conclusion that it behaves as intended.
When comparing the index (with a new file) to the commit, it looks like the new file was removed. If you do it the other way around, as in repo.head.commit.diff(), which is equivalent to repo.head.commit.diff(git.Diffable.Index), which will show the new file as added.

However, I'd be happy to learn how you would improve the respective part of the documentation in order to make clearer what to expect.

Please note that I am closing the issue in the meanwhile as I believe a separate PR or issue is better suited to track possible documentation changes.

[dudicoco]

@Byron just came across this weird behaviour myself. Using repo.head.commit.diff() does not show the change the other way around for me. Any suggestions?

Thanks

[dudicoco]

Managed to solve this:

diff = repo.commit('origin/HEAD').diff('HEAD')