Fails on import with custom exception

[vidartf]

On Windows, without git available on path, the following happens on import of GitPython:

[package stack]
 from git.exc import GitError
 File "C:\Miniconda3\lib\site-packages\git\__init__.py", line 45, in <module>
 from git.repo import Repo # @NoMove @IgnorePep8
 File "C:\Miniconda3\lib\site-packages\git\repo\__init__.py", line 4, in <module>
 from .base import *
 File "C:\Miniconda3\lib\site-packages\git\repo\base.py", line 31, in <module>
 from git.remote import Remote, add_progress, to_progress_instance
 File "C:\Miniconda3\lib\site-packages\git\remote.py", line 190, in <module>
 class FetchInfo(object):
 File "C:\Miniconda3\lib\site-packages\git\remote.py", line 219, in FetchInfo
 v = Git().version_info[:2]
 File "C:\Miniconda3\lib\site-packages\git\cmd.py", line 461, in version_info
 return self._version_info
 File "C:\Miniconda3\lib\site-packages\git\cmd.py", line 424, in __getattr__
 return LazyMixin.__getattr__(self, name)
 File "C:\Miniconda3\lib\site-packages\gitdb\util.py", line 256, in __getattr__
 self._set_cache_(attr)
 File "C:\Miniconda3\lib\site-packages\git\cmd.py", line 444, in _set_cache_
 version_numbers = self._call_process('version').split(' ')[2]
 File "C:\Miniconda3\lib\site-packages\git\cmd.py", line 877, in _call_process
 return self.execute(call, **exec_kwargs)
 File "C:\Miniconda3\lib\site-packages\git\cmd.py", line 602, in execute
 raise GitCommandNotFound(command, err)
git.exc.GitCommandNotFound: Cmd('git') not found due to: FileNotFoundError('[WinError 2] The system cannot find the file specified')
 cmdline: git version

Since it fails while trying to import the exception type that it raises (GitError), the only way to catch the error is with a try: ... except Exception: block, which is needlessly wide. It would be nice if a better pattern was available for conditional use of the package.

[vidartf]

(this was using version 2.1.5)

[vidartf]

It seems like this was introduced in 2.1.4 (2.1.3 imports flawlessly even without git on path).

[scottbelden]

Wow, I was literally just about to make this ticket. At the moment my only option to conditionally import is something like:

try:
 import git
except:
 pass

But as @vidartf notes, that's less than ideal.

[Byron]

Thanks for reporting this issue! I believe that the problem originates here, and could be solved by delaying that particular operation until that _flag_map is actually required. This would also decrease the time it takes to import GitPython.
It looks like a decent python exercise to do that, in case one would want to contribute a PR :).

Personally I believe at the time of import, nothing but ImportErrors should be thrown, which is clearly violated here.

[kenodegard]

A possible solution is that of #640 where import git succeeds with or without git available. This then allows the user to dynamically set their git path after import (as would be the case if a program needed to first read and parse a config file which contains the git path).

The above mentioned PR introduces a git.refresh function which allows the user to set their git path during runtime and hence refreshes both the GIT_PYTHON_GIT_EXECUTABLE in the git.cmd.Git object but also the _flag_map in the git.remote.FetchInfo object.

[Byron]

This should be fixed with the latest, upcoming release, v2.1.7.