Fix #13084

[madbird1304]

Fix for issue caused by using shlex to quote executable path.
Sorry, I've introduced this bug.
To fix this, let's replace shlex.quote with subprocess.list2cmd(). It

• uses " to quote path,
• performs quoting only if necessary

@MrMino , could you take a look please?

[MrMino]

Ugh... I didn't wanted list2cmdline cause it's MSC specific but it turns out that shlex.quote also isn't "platform agnostic". It didn't occur to me that single quotes would have different meaning to double quotes - I should've tested it on Windows.

One other argument against using list2cmdline: it isn't really "public" in the same sense other methods of subprocess are. It's an implementation detail, not a "public API".

Furthermore, I feel like introducing MSC shell semantics on all other platforms will introduce subtle bugs and edge cases. A simple .replace("'", "\"") also isn't enough, since virtualenv paths can contain " on UNIX-es.

At this point I'm questioning whether this should even use shell.system. I should probably look into creating a argv-style API for shell commands in magics. But let's fix this first. Any changes to the shell.system API would probably need to go into 8.0, and we need to get the fix into 7.27.

I don't see any other option than using something like if sys.platform == "win32": "\"" + s + "\""; else: shlex.quote(...).

[madbird1304]

@MrMino , you said:

At this point I'm questioning whether this should even use shell.system.

Then let's just get rid of it?

[MrMino]

We cannot get rid of or substantially change shell.system until at least 8.0, and even then I'd rather not add more to an already bulky major release. The fix has to go into the next 7.x.

Coming up with something that is a valid replacement for it isn't trivial either.

Unless there's another option, I'd rather bodge it in with a sys.platform branch.

[MrMino]

Exactly what I had in mind :). Thanks!

If you add a whats-new entry and fix the linter errors, I'll merge.

Edit: @madbird1304 since I'm on vacation next week, and I don't want to postpone it till the next release, I went ahead and fixed the lint for you. Hope you don't mind.

[MrMino]

Thanks @madbird1304!

[madbird1304]

Sorry for late reply. I was busy last week, so thanks for finishing that without me.