pip config and $EDITOR containing arguments

Environment

• pip version: 19.2.3
• Python version: 3.8
• OS: Linux

Description

pip config edit is supposed to open the program specified by environment variable Editor if it’s set. Actually if the env is a program with its options, pip will treat the whole thing as the program name and throws a FileNotFoundError.

Expected behavior

pip config edit open the editor with options set.

How to Reproduce

1. export EDITOR="nvim --noplugin"; pip config edit

Output

ERROR: Exception:
Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/pip/_internal/cli/base_command.py", line 188, in main
    status = self.run(options, args)
  File "/usr/lib/python3.8/site-packages/pip/_internal/commands/configuration.py", line 136, in run
    handlers[action](options, args[1:])
  File "/usr/lib/python3.8/site-packages/pip/_internal/commands/configuration.py", line 216, in open_in_editor
    subprocess.check_call([editor, fname])
  File "/usr/lib/python3.8/subprocess.py", line 359, in check_call
    retcode = call(*popenargs, **kwargs)
  File "/usr/lib/python3.8/subprocess.py", line 340, in call
    with Popen(*popenargs, **kwargs) as p:
  File "/usr/lib/python3.8/subprocess.py", line 854, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.8/subprocess.py", line 1702, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'nvim  #--noplugin'

My Fix #7391

[uranusjr]

I feel we should yield and just use shell=True if needed. I still think it’s wrong, but it is what users expect because everybody is doing it.

[chrahunt]

On Windows it would also need to check PATHEXT. And we’d need tests for the same. Given that, I would no longer implement this for Python 2. We can just use the existing behavior for Python 2 and handle args in Python 3.