Nix: ~/.config/nix/nix.conf overrides values of /etc/nix/nix.conf

[domenkozar]

I'd expect substituters in ~/.config/nix/nix.conf to be appended on top of the system /etc/nix/nix.conf, but currently, Nix overrides them.

[LnL7]

There's extra-substituters, same for certain other options.

[edolstra]

I'm not sure if append is desirable behaviour in general. What if you want to override? Also, should it prepend or append?

Maybe appending could be a special syntax, e.g.

substituters += https://...

or --substituters +https://....

[dezgeg]

For the command line syntax, the GNU command line guidelines for long options generally supports --foo=bar to be equivalent to --foo bar. So if we supported that, then --substituters+=https://foo.bar would be a quite logical extension.

[ElvishJerricco]

Additionally, it'd be nice if there were ways to specify many config files other than the two default ones.

[grahamc]

Configuration files can use import to load additional config files. Does that suit your needs, @ElvishJerricco?

[ElvishJerricco]

@grahamc Had no idea.That's awesome. Is that documented? And I assume it still causes overwriting of options?

[grahamc]

Oops, I meant include -- yes it is documented: https://nixos.org/nix/manual/#description-41

[domenkozar]

Using += seems fine to me as long as there's an equivalent for --options substituters ..., something like --options-append substituters ...

[NorfairKing]

I just ran into a very confusing issue where I had a shell alias in a shellHook with multiple --option trusted-public-keys options.
Suddenly my machine was recompiling the linux kernel after a nixpkgs upgrade. I couldn't figure out what was wrong until @domenkozar pointed out that --option trusted-public-keys overrides instead of appending. So :+1: on this issue!