Child processes can inherit initial environment variables after hide-env

[IanManske]

Describe the bug

When we spawn child processes, we do not clear environment variables. This means it is possible for child processes to inherit environment variables that are supposed to be hidden via hide-env.

How to reproduce

1. set a environment variable in the parent shell.

$env.TEST = 1

2. start a child shell with the following command string.

^$nu.current-exe -c "hide-env TEST; ^$nu.current-exe -c '$env.TEST'"

The child shell first hides the TEST environment variable. It will not be able to use the environment variable directly. However, the child shell then spawns a grandchild shell. The grandchild is able to access the TEST environment variable and will print 1.

Expected behavior

An error saying that the TEST environment variable could not be found.

Screenshots

No response

Configuration

Bug is present on 0.92.2, 0.93.0, latest main, and maybe since the beginning of time.

key	value
version	0.92.2
branch	makepkg
commit_hash	2a08a18
build_os	linux-x86_64
build_target	x86_64-unknown-linux-gnu
rust_version	rustc 1.77.1 (7cf61ebde 2024-03-27) (Arch Linux rust 1:1.77.1-2)
cargo_version	cargo 1.77.1
build_time	2024-04-11 08:40:50 +00:00
build_rust_channel	release
allocator	mimalloc
features	dataframe, default, sqlite, trash, which
installed_plugins

Additional context

No response

[fdncred]

I've seen this for a long time. I thought I had another issue related around hide.

Yup, found it #7937 and #6593

Related starship/starship#4386