[Feature]: Support conda / buildFHSUserEnv

[tbenst]

Is your feature request related to a problem? Please describe.
Occasionally, I need to use conda on my NixOS box. Normally, I'd use nix-shell to enter a buildFHSUserEnv, then run VSCode. This workflow isn't possible with remote-ssh, however, and this is where nix-env-selector is fantastic.

nix-env-selector uses nix-shell --run and this is unfortunately unsupported for buildFHSUserEnv. <- also has a workaround however.

Describe the solution you'd like
I'd like to be able to use buildFHSUserEnv with nix-env-selector. A hacky solution would be to grep for "buildFHSUserEnv" in the *.nix file, and if found, to instead pass --argstr run XXX. Then, in the FHS, I could write `runScript = "bash --rcfile <(echo '. ~/.bashrc; conda activate caiman; ${run}')";

Describe alternatives you've considered
For shebang scripts, I use the workaround linked above: create an executable called conda for my conda.nix buildFHSUserEnv:

#!/usr/bin/env bash
set -euo pipefail
fhs="/Computer/shell/conda.nix"
function run {
  nix-shell --pure --argstr run "$*" "${fhs}"
}
if [[ $# -eq 0 ]]; then
  run bash
else
  run "conda $@"
fi

Then, in a python script I do (-S is for passing multiple arguments)

#!/usr/bin/env -S conda run -n caiman python
import caiman
print("hello world")

Unfortunately, I haven't succeeded in hooking in my conda wrapper with VScode's python interpreter selector.

[arrterian]

@tbenst I investigated the issue briefly. Sad but we need to run some shell command as process fork from node js and I didn't find the solution with buildFHSUserEnv if you can help to get env output inside the environment by forking process it can help in another way I think we should close the issue as unresolved in this context.

[tbenst]

Hi @arrterian, thanks for looking into this! I didn’t quite follow your comment, could you elaborate or point me to code? happy to help. Thanks!

[arrterian]

@tbenst
Now the extension works this way. https://github.com/arrterian/nix-env-selector/blob/master/src/helpers.ts#L22
We run env command inside nix-shell then parse the output through dotenv, then set each variable to node-process on extension host via process.env. If we can get the output from buildFHSUserEnv via forking some process I will able to implement that in extension. But I can't find a solution to how to do that.