Workbench: make shell pure

[andreabedini]

Description

This change makes the workbench shell pure. Nix will do its best to strip off the current environment and will give the user a pristine shell, where the only environment variables are set by nix. This prevents unintentional mingling of system- and nix-provided libraries.

Tested with:

• make shell
• start-cluster
• wb a
• wb a std 2023-04-26-08-40-28344-default-bage-sup
• wb a compare 2023-04-26-08-40-28344-default-bage-sup 2023-04-26-08-40-28344-default-bage-sup

[mgmeier]

Great, thanks @andreabedini

[NadiaYvette]

Great, thanks @andreabedini

This fixes the LD_LIBRARY_PATH build issue I was having. I see something unusual with ps not being found in my path when I try to run start-cluster, though I'm not sure if that's my end again or not.

[andreabedini]

@fmaste had some issues running the nomad backend with this change. Is it still a problem?

[angerman]

Great, thanks @andreabedini

This fixes the LD_LIBRARY_PATH build issue I was having. I see something unusual with ps not being found in my path when I try to run start-cluster, though I'm not sure if that's my end again or not.

This is probably related. --pure ensures that there is no leakage from the env prior to the nix-shell call into the shell. So it would ingore any LD_LIBRARY_PATH values, as well as PATH values.

Do check the PATH var inside the shell, and check outside of the shell where ps lives (e.g. with which ps).

[andreabedini]

Closing for now, we wil revisit another time.