--python flag is broken on Windows #1205
Description
Describe the bug
The --python flag used to work with a executable name in the PATH. E.g. pipx install --python python3.12.exe ... worked, if python3.12.exe was found on the path.
Since #1168, however, this does no longer work. See analysis below.
$ where python3.12.exe
C:\Users\Dominik\AppData\Local\Microsoft\WindowsApps\python3.12.exe
$ pipx install --python python3.12.exe flit
creating virtual environment...
Traceback (most recent call last):
File "<frozen runpy>", line 198, in _run_module_as_main
File "<frozen runpy>", line 88, in _run_code
File "C:\not_of_interest\Scripts\pipx.exe\__main__.py", line 7, in <module>
File "C:\not_of_interest\Lib\site-packages\pipx\main.py", line 911, in cli
return run_pipx_command(parsed_pipx_args)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\not_of_interest\Lib\site-packages\pipx\main.py", line 212, in run_pipx_command
return commands.install(
^^^^^^^^^^^^^^^^^
File "C:\not_of_interest\Lib\site-packages\pipx\commands\install.py", line 83, in install
venv.create_venv(venv_args, pip_args, override_shared)
File "C:\not_of_interest\Lib\site-packages\pipx\venv.py", line 160, in create_venv
venv_process = run_subprocess(cmd + venv_args + [str(self.root)])
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\not_of_interest\Lib\site-packages\pipx\util.py", line 179, in run_subprocess
completed_process = subprocess.run(
^^^^^^^^^^^^^^^
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.12_3.12.496.0_x64__qbz5n2kfra8p0\Lib\subprocess.py", line 548, in run
with Popen(*popenargs, **kwargs) as process:
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.12_3.12.496.0_x64__qbz5n2kfra8p0\Lib\subprocess.py", line 1026, in __init__
self._execute_child(args, executable, preexec_fn, close_fds,
File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.12_3.12.496.0_x64__qbz5n2kfra8p0\Lib\subprocess.py", line 1538, in _execute_child
hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [WinError 2] Das System kann die angegebene Datei nicht finden
How to reproduce
On a windows system, pass any python executable available in the PATH.
Expected behavior
It should be possible to pass executables to be found on the PATH to the --python flag.
Analysis
The changes introduced by #1168 call os.path.realpath on the argument before giving it to subprocess.run. This causes the current working directory to be prepended and subprocess.run can not lookup the executable, as it gets a resolved/absolute (non-existing) path. Note, this is even shadowed in the verbose log, as this prints a version of the cmd, which was not passed through os.path.realpath.
See my initial direct suggestion in #1186 (comment) to fix (or at least workaround) the issue. I tried to be lazy and not open an issue, but @Gitznik rightfully told me to do so.