fix(cmdline): prevent hangs from shellcmd completion on win32/wsl

[soifou]

This change makes the previous attempt to disable shell completion in Windows environments more robust:

• Handles both Windows and WSL, instead of only targeting Windows.
• Handles all shellcmd completions, e.g. :term, not just the :! command.
• Instead of disabling shellcmd completions entirely, temporarily remove system32 from PATH. This avoids hangs while still allowing completion items from other locations to be displayed.

Closes #1926
Related #1029

[soifou]

Need some feedback from WSL users before this PR can get merged.

[vinnymeller]

not super knowledgeable about either wsl or lua but I tested this out and did run into a couple problems

system stuff:

~ uname -r
5.15.167.4-microsoft-standard-WSL2

~ wsl.exe --version
WSL version: 2.4.12.0
Kernel version: 5.15.167.4-1
WSLg version: 1.0.65
MSRDC version: 1.2.5716
Direct3D version: 1.611.1-81528511
DXCore version: 10.0.26100.1-240331-1435.ge-release
Windows version: 10.0.26100.4349

~ nvim --version
NVIM v0.12.0-nightly+0d65866
Build type: Release
LuaJIT 2.1.1741730670
Run "nvim -V1 -v" for more info

separator issue

For some reason the separator logic here wasn't working as intended(i think?):

:lua vim.print(vim.fn.has('win32'))
0

:lua vim.print(vim.fn.has('wsl'))
1

:lua vim.print(vim.fn.has('win32') and ';' or ':')
;

extra windows paths

The other issue I ran into is that I had more than just /mnt/c/windows/system32 in my path:

~ print -rl $path | grep /mnt/c
/mnt/c/WINDOWS/system32
/mnt/c/WINDOWS
/mnt/c/WINDOWS/System32/Wbem
/mnt/c/WINDOWS/System32/WindowsPowerShell/v1.0/
/mnt/c/WINDOWS/System32/OpenSSH/
/mnt/c/Program Files/NVIDIA Corporation/NVIDIA app/NvDLISR
/mnt/c/Program Files (x86)/NVIDIA Corporation/PhysX/Common
/mnt/c/Users/vinny/AppData/Local/Microsoft/WindowsApps

I opened a branch & pr in my fork that "fixes" these issues here: https://github.com/vinnymeller/blink.cmp/pull/3/files

I don't know that my solution is close to something you'd want to do but my version works as expected for me - basically having any /mnt/c/* path in my PATH causes cmdline completions to completely freeze. not sure if that is a universal experience but something specific to my installation, but I had to remove all of them to fix the issue

[soifou]

Hey, thanks for digging into this! Honestly, I'm not super knowledgeable either. I just threw that patch together and tested quickly on a basic Windows VM (no WSL).

Good catch on vim.fn.has, returning 0 or 1 instead of a boolean is a classic Lua gotcha!

basically having any /mnt/c/* path in my PATH causes cmdline completions to completely freeze.

Yeah, that makes sense. It’s because of the slow cross-filesystem performance between WSL and Windows. Pretty much anything under /mnt is going to be sluggish. So it's better to skip all /mnt.

On regular Windows, though, I think just blacklisting System32 should be enough (I tested it 😄).

Anyway, thanks again for your help, I just pushed an update with all these points and added you as a co-author in the commit. If you could confirm that it’s still working fine on your side, that would be great.

[vinnymeller]

@soifou works perfectly for me 😃

[saghen]

Tysm!