Multiple Errors while execution of Tests

[deepak1725]

Environment

• pip version: 19.3.1
• Python version: 3.7.3
• OS: Fedora 29

Description
Tried Executing very first command
$tox -e py36

Expected behavior
A Good success message

How to Reproduce
Maybe some environment issue, or some command is missing.

1. Installed Tox
2. Then Installed Python3.8
3. Then Executed $tox -e py3.7 >> error.txt

Output

Attached Output File
[error.txt](https://github.com/pypa/pip/files/4035602/error.txt)

[uranusjr]

Could you help me run the following in python3.7:

import subprocess
subprocess.check_call(['any-command-that-does-not-exist'])

and see if it raises NotADirectoryError?

All errors (afaict) are basically one problem: you don’t have Mercurial installed. The problem though is that pip already handles this, by catching FileNotFoundError (actually, an equivalent that works on Python 2, but let’s ignore that detail now), but your OS somehow throws a different error when it cannot find a command, NotADirectoryError, which pip does not handle.

The easy fix is to, well, handle that. But this is kind of a weird behaviour on the OS’s part. Does someone have any insight into why the OS might do that, and whether it’s a good idea to accommodate it?

[deepak1725]

@uranusjr Thanks for Quick response.
Here we go:

Python 3.7.3 (default, May 11 2019, 00:45:16) 
[GCC 8.3.1 20190223 (Red Hat 8.3.1-2)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import subprocess
>>> subprocess.check_call(['any-command-that-does-not-exist'])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib64/python3.7/subprocess.py", line 342, in check_call
    retcode = call(*popenargs, **kwargs)
  File "/usr/lib64/python3.7/subprocess.py", line 323, in call
    with Popen(*popenargs, **kwargs) as p:
  File "/usr/lib64/python3.7/subprocess.py", line 775, in __init__
    restore_signals, start_new_session)
  File "/usr/lib64/python3.7/subprocess.py", line 1522, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
NotADirectoryError: [Errno 20] Not a directory: 'any-command-that-does-not-exist'

Above Error is same for Python3.6 and Python3.7 each

[deepak1725]

After Install Mercurial, It is left with 2 Errors only.
error2.txt

[uranusjr]

The two errors are the same, something like

FileNotFoundError: [Errno 2] No such file or directory: "/tmp/pytest-of-deepshar/pytest-13/test_freeze_mercurial_clone0/workspace/scratch/pip-test-package/*** failed to import extension hgext.qct: missing attributes: norepo, optionalrepo, inferrepo\n*** (use @command decorator to register '^qct|commit-tool')\n/tmp/pytest-of-deepshar/pytest-13/test_freeze_mercurial_clone0/workspace/scratch/pip-test-package"

I believe they are tracked in #7545.

[uranusjr]

Hmm, I just checked this on a fresh Fedora 29 Docker image:

>>> import subprocess
>>> subprocess.check_call(['asdasdfdgfgfg'])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib64/python3.7/subprocess.py", line 342, in check_call
    retcode = call(*popenargs, **kwargs)
  File "/usr/lib64/python3.7/subprocess.py", line 323, in call
    with Popen(*popenargs, **kwargs) as p:
  File "/usr/lib64/python3.7/subprocess.py", line 775, in __init__
    restore_signals, start_new_session)
  File "/usr/lib64/python3.7/subprocess.py", line 1522, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'asdasdfdgfgfg': 'asdasdfdgfgfg'

So it seems the stdlib is doing the correct thing by default, and the NotADirectory exception you get is indeed an environment problem. I don’t know what it is though. :(

[pfmoore]

Could it be related to permissions? I'm not a Linux user myself, but I seem to recall Linux can report problems with unusual combinations of permissions in odd ways.

Do you have a directory on your $PATH with unusual permissions?

[deepak1725]

Could it be related to permissions? I'm not a Linux user myself, but I seem to recall Linux can report problems with unusual combinations of permissions in odd ways.

Do you have a directory on your $PATH with unusual permissions?

AFAIK No

[deepak1725]

Closing as @uranusjr specified its system-specific.
Workaround: Wrote a Docker File.

Feel Free to reopen if someone else faced similar issues.