shellStartup doesn't work properly in a devcontainer #986
Description
I have found an interesting bug. You can reproduce it by opening the MRE below in VSCode, then reopening it in a devcontainer, and then opening the workspace configuration provided.
All terminals, Python debugging, etc., will select the Python environment of the last Python file you have opened in the editor. If you don't open any files, you'll see all terminals, even the ones that should activate proj2 will activate proj1 instead. The intriguing part is that this happens only in a devcontainer and only when using shellStartup. Outside of it is fine.
I've checked the trace logs, and it seems that createProcess over here has the correct env vars set in shellLaunchConfig but has the wrong ones in env and those are overwriting the ones passed by the Python Environments extension.