Failure to run as Windows Service ( [WinError 6] on subprocess.Popen )

[mikkelcp1]

While configuring a working application to be run via a Windows Service (Windows 7) ( via nssm ), the application was failing (only when ran as a Windows Service) with:

2018-02-07 14:05:51.560:   File "C:\ProgramData\Anaconda3\envs\ccns\lib\site-packages\git\cmd.py", line 294, in refresh
2018-02-07 14:05:51.560:     raise ImportError(err)
2018-02-07 14:05:51.560: ImportError: Bad git executable.
2018-02-07 14:05:51.560: The git executable must be specified in one of the following ways:
2018-02-07 14:05:51.560:     - be included in your $PATH
2018-02-07 14:05:51.560:     - be set via $GIT_PYTHON_GIT_EXECUTABLE
2018-02-07 14:05:51.560:     - explicitly set via git.refresh()

After debugging the issue a bit, the problem was coming from the Popen call in Git.execute() - throwing Exception '[WinError 6] The handle is invalid'

The issue / workaround is described here (see stackoverflow link) - subprocess throws exception where it fails to find std-in handle with argument stdin=None to Popen().
Using the same work around from the link corrected my issue running as a Windows Service:

The work-around, was to add something like the stdout_sink for stdin (see below) prior to calling Popen() within Git.execute():

  log.debug("Popen(%s, cwd=%s, universal_newlines=%s, shell=%s)",
                  command, cwd, universal_newlines, shell)
  + if( istream is None):
  +          istream = subprocess.DEVNULL
  try:
            proc = Popen(command,

Not sure this if is the best solution, but it allows me to use GitPython running as Windows Service.

[Byron]

Thanks a lot for the summary! It looks like a simple change that could easily become a PR. The only problem might be that subprocess.DEVNULL is not available in all versions of Python that GitPython supports.

[yarikoptic]

FWIW, we are experiencing the flood of similar issues on windows in DataLad. Unfortunately I do not see a permalink to the appveyor log, so here is a sample of tracebacks:

======================================================================
ERROR: datalad.support.tests.test_gitrepo.test_GitRepo_get_merge_base
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Miniconda35\envs\test-environment\lib\site-packages\git\cmd.py", line 735, in execute
    **subprocess_kwargs
  File "C:\Miniconda35\envs\test-environment\lib\subprocess.py", line 845, in __init__
    _cleanup()
  File "C:\Miniconda35\envs\test-environment\lib\subprocess.py", line 505, in _cleanup
    res = inst._internal_poll(_deadstate=sys.maxsize)
  File "C:\Miniconda35\envs\test-environment\lib\subprocess.py", line 1255, in _internal_poll
    if _WaitForSingleObject(self._handle, 0) == _WAIT_OBJECT_0:
OSError: [WinError 6] The handle is invalid
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "C:\Miniconda35\envs\test-environment\lib\site-packages\nose\case.py", line 198, in runTest
    self.test(*self.arg)
  File "C:\Miniconda35\envs\test-environment\lib\site-packages\datalad\tests\utils.py", line 591, in newfunc
    return t(*(arg + (filename,)), **kw)
  File "C:\Miniconda35\envs\test-environment\lib\site-packages\datalad\support\tests\test_gitrepo.py", line 802, in test_GitRepo_get_merge_base
    repo = GitRepo(src, create=True)
  File "C:\Miniconda35\envs\test-environment\lib\site-packages\datalad\support\repo.py", line 146, in __call__
    instance = type.__call__(cls, *new_args, **new_kwargs)
  File "C:\Miniconda35\envs\test-environment\lib\site-packages\datalad\support\gitrepo.py", line 586, in __init__
    **git_opts)
  File "C:\Miniconda35\envs\test-environment\lib\site-packages\datalad\cmd.py", line 189, in __call__
    return self.call(cmd, *args, **kwargs)
  File "C:\Miniconda35\envs\test-environment\lib\site-packages\datalad\cmd.py", line 570, in call
    return f(*args, **kwargs)
  File "C:\Miniconda35\envs\test-environment\lib\site-packages\git\repo\base.py", line 906, in init
    git.init(**kwargs)
  File "C:\Miniconda35\envs\test-environment\lib\site-packages\git\cmd.py", line 548, in <lambda>
    return lambda *args, **kwargs: self._call_process(name, *args, **kwargs)
  File "C:\Miniconda35\envs\test-environment\lib\site-packages\git\cmd.py", line 1014, in _call_process
    return self.execute(call, **exec_kwargs)
  File "C:\Miniconda35\envs\test-environment\lib\site-packages\git\cmd.py", line 738, in execute
    raise GitCommandNotFound(command, err)
git.exc.GitCommandNotFound: Cmd('git') not found due to: OSError('[WinError 6] The handle is invalid')
  cmdline: git init

On a quick try the aforementioned trick with stdin didn't help.
It would be really appreciated if someone got down to the bottom of the issue here.