When using Popen with shell=True, the output of the repr is not particularly user friendly. 

When using the form `p = Popen('python --version'.split())`, the output is reasonably output in a user friendly form of `<Popen: returncode: None args: ['python', '--version']>`. 

However, when running with `shell=True`, the output is mangled.

For example, trying to run `python --help` via `p = Popen('python --version', shell=True)` yields the following output.

`<Popen: returncode: None args: ['p', 'y', 't', 'h', 'o', 'n', ' ', '-', '-',...>`

The original change appears to be motivated by https://bugs.python.org/issue38724 

and the PR here:

https://github.com/python/cpython/pull/17151/files

Actually, the problem is independent of the value of "shell", the __repr__ function from the initial PR that introduced it expects "args" to be a sequence and converts it to a list.

There's a PR up with removed `list` call as well as improved test coverage for the case where args is passed into Popen as a string. 

Hopefully this can get merged before things starting getting crazy with the 3.10 release crunch.

There also appears to be an issue when args are provided as a `pathlib.Path` instance.


Python 3.9.2 | packaged by conda-forge | (default, Feb 21 2021, 05:02:20) 
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IPython 7.22.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: from subprocess import Popen

In [2]: from pathlib import Path

In [3]: p = Path('/usr/local/bin/gtrue')

In [4]: x = Popen(p)

In [5]: repr(x)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-5-5091dd558c19> in <module>
----> 1 repr(x)

~/opt/miniconda3/envs/core/lib/python3.9/subprocess.py in __repr__(self)
    990         obj_repr = (
    991             f"<{self.__class__.__name__}: "
--> 992             f"returncode: {self.returncode} args: {list(self.args)!r}>"
    993         )
    994         if len(obj_repr) > 80:

TypeError: 'PosixPath' object is not iterable

New changeset db0c5b786df961785ae8c803f5572ae0c8dadcc7 by M. Kocher in branch 'master':
bpo-43776: Remove list call from args in Popen repr (GH-25338)
https://github.com/python/cpython/commit/db0c5b786df961785ae8c803f5572ae0c8dadcc7

New changeset 5a8ddcc4524dca3880d7fc2818814ffae1cfb8a2 by Gregory P. Smith in branch '3.9':
[3.9] bpo-43776: Remove list call from args in Popen repr (GH-25338) (GH-26510)
https://github.com/python/cpython/commit/5a8ddcc4524dca3880d7fc2818814ffae1cfb8a2