"Path" env variable gets stomped - windows

[sharpencrag]

Type: Bug

Windows environment variables are supposed to be case-insensitive; however, if VS Code is launched from a shell where the Path variable is PATH instead of Path (such as one created by Python), Code's environment will create a second Path variable instead of inheriting PATH from the parent shell.

Steps:

1. Create a shell that uses PATH instead of Path. The simplest way I found is to just create a shell from python:

# make_shell.py
import os
import subprocess

command = ["cmd", "/Q", "/K"]
print("Path is now PATH")
subprocess.call(command, shell=True, env=os.environ)

> python make_shell.py
Path is now PATH
> |

2. Launch VS Code from this new shell

3. Check your environment variables in the terminal

cmd: set path will show both PATH and Path -- modifications to PATH made upstream are not be reflected on Path

pwsh: trying to use dir env: will throw an error. Using write-host $env:path will show Path, and any changes to PATH upstream will be lost

Same effect occurs on Insider build. I don't know when exactly this behavior changed, but pre-configured shells are a pretty big piece of some developer tools we use

VS Code version: Code 1.97.2 (e54c774, 2025-02-12T23:20:35.343Z)
OS version: Windows_NT x64 10.0.26100
Modes:

System Info

Item	Value
CPUs	AMD Ryzen 9 7900X3D 12-Core Processor (24 x 4400)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: enabled_on direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: disabled_off video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	63.73GB (44.66GB free)
Process Argv
Screen Reader	no
VM	0%

Extensions disabled

[Tyriar]

You said cmd shows both Path and PATH? I don't see that with your repro, do you see something different to this?

modifications to PATH made upstream are not be reflected on Path

By modifying PATH inside this cmd session, it's expected to NOT be carried over to the "upstream" process (pwsh or python in my example)?

I see the same thing for pwsh. Does setting "terminal.integrated.experimental.windowsUseConptyDll": true help?

[sharpencrag]

@Tyriar -- Thanks for looking into this! I use Python to create a cmd session, then launch Code from that session -- it's only in the VS Code terminal that you can see the duplicated path variable.

This is an even easier way to demonstrate, you can launch Code directly from python without making a new interactive session:

# launch_code.py
import os
import subprocess

print("Path is now PATH")
subprocess.call(["code", "--new-window"], shell=True, env=os.environ)

Tried with terminal.integrated.experimental.windowsUseConptyDll - no change.