fix: fix incoherent beginning whitespace

[cardoeng]

Some repositories contain files / directories beginning by a space in their history (example : react-component/field-form@0e81dc0).

The current version of GitPython returns this space sometimes when doing a diff (depending on whether the space is in a_path or b_path).

Python 3.12.3 [...] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import git
>>> git.Repo.clone_from("https://github.com/react-component/field-form", "field-form") # example repository
<git.repo.base.Repo '/tmp/field-form/.git'>
>>> r = git.Repo("field-form")
>>> c = r.commit("0e81dc0d69d198d644b44eb4f84d875777c03581") # commit where there is a space
>>> d1 = c.diff(c.parents[0])[0] # first diff
>>> d1.a_path
'.github/workflows/main.yml'
>>> d1.b_path
' .github/workflows/main.yml' # note the space in the beginning
>>> d2 = c.parents[0].diff(c)[0] # same diff but inverted commits
>>> d2.a_path
'.github/workflows/main.yml' # there is no space
>>> d2.b_path
'.github/workflows/main.yml'

This is due to a strip being done to the path (see the only line changed in diff.py). This PR make a simple change by not stripping the spaces, but only new lines (we can also add other characters if needed) so the behavior stays coherent and the white space is given when doing a diff. An alternative would be to remove the strip (some tests started failing when doing so...).

>>> r = git.Repo("field-form")
>>> c = r.commit("0e81dc0d69d198d644b44eb4f84d875777c03581")
>>> d1 = c.diff(c.parents[0])[0] 
>>> d1.a_path
'.github/workflows/main.yml'
>>> d1.b_path
' .github/workflows/main.yml' # note the space
>>> d2 = c.parents[0].diff(c)[0]
>>> d2.a_path
' .github/workflows/main.yml' # the space is there
>>> d2.b_path
'.github/workflows/main.yml'

[Byron]

Thanks a lot for this fix, that's better!

I wonder if the strip("\n") has to happen at all, it's unusual to have newlines in paths anyway, and if they are there, they should not be removed.

In other words, what happens if there is no strip() call?

[cardoeng]

I tried removing the strip() call, and it seems two tests related to copied or renamed files during diff started failing :

FAILED test/test_diff.py::TestDiff::test_diff_with_copied_file - AssertionError: 'test2.txt\n' != 'test2.txt'
FAILED test/test_diff.py::TestDiff::test_diff_with_rename - AssertionError: 'that\n' != 'that'

A \n seems to be added at the end of a_path and b_path in certain cases if we remove completely the strip(). (I am not fully familiar with the internal working of GitPython, so I cannot really give more details as to why...)

[Byron]

Thanks for trying it out, and it seems there is nothing left to do here but to hit merge.

Thanks again for contributing :)!