nix-shell --pure

[CSVdB]

Right now, nix dev-shell forms a modern version of nix-shell --impure. There is no modernization of nix-shell --pure yet though.

[matthewbauer]

Nice to see dev-shell being added!

But I always thought --pure was a weird feature. When do you actually want a pure shell? Doesn't nix build already provide purity? I don't see the use in providing a halfway thing between nix build and nix dev-shell. You either have purity or you don't.

[AmineChikhaoui]

@matthewbauer You can't do development inside nix build, so --pure is actually useful to make sure you're not inheriting anything from your local environment.

[matthewbauer]

I just don't think anyone really wants purity when doing development. Some might think they do, which is why things like Docker are popular. But, there are many good reasons to inherit from the local environment. Things like localizations, timezones, dev tools, and other user configurations need to come from the parent environment to work correctly. Breaking these things in pursuit of "purity" seems like a bad idea. Otherwise, you can always do:

env -i nix dev-shell

to get the pure environment.

[mkenigs]

Was looking at this as well as #3107. Instead of passing env vars through an rcfile, would it work to just set all of them before the call to exec or maybe use execvpe instead? Then if pure is desired just clear everything other than exceptions beforehand.

Think this would potentially help #3107 - environment would be set independent of what shell is used, but bashFunctions could be passed in an rcfile only in the case of bash.

Would that work/be helpful for me try to PR?

[CMCDragonkai]

Is there documentation on dev-shell?

[edolstra]

nix dev-shell has an option --ignore-environment now, so this can be closed.

[CMCDragonkai]

Is nix dev-shell deprecating nix-shell?

…

On 2 February 2020 22:50:53 GMT+11:00, Eelco Dolstra ***@***.***> wrote: `nix dev-shell` has an option `--ignore-environment` now, so this can be closed. -- You are receiving this because you commented. Reply to this email directly or view it on GitHub: #2813 (comment)

-- Sent from my Android device with K-9 Mail. Please excuse my brevity.

[zimbatm]

@CMCDragonkai this is only touching the flakes branch of nix. Everybody should keep using nix-shell until flakes is ready.