shell.nix: Update from scons to cmake

[haslersn]

No description provided.

[Be-ing]

@poelzi could you review this?

[matthiasbeyer]

LGTM

[Be-ing]

@matthiasbeyer thanks. I'll take your word for it because I don't know much about Nix.

[uklotzde]

Thank you, Matze :)

[matthiasbeyer]

Yeah it all looks pretty straight-forward, no daemons that I can see, so I figured I just ACK this and maybe that's enough for you guys! ❤️

[poelzi]

I don't understand the change from default.nix to shell.nix. I use nix-build to produce a nix derivate which i use daytoday. I use nix-shell to get a build environment. Your change destroys my first use case while providing no benefits.

[matthiasbeyer]

no, nix-shell automatically uses shell.nix and if that's not available default.nix, but default.nix can also be used to package the repo without any further investigation.

Executing nix-shell should have the same effect before this change and after this change.

Edit:

Building should afaik still be possible using nix-build ./shell.nix then... not sure though, maybe @haslersn knows?

[haslersn]

I don't understand the change from default.nix to shell.nix. I use nix-build to produce a nix derivate which i use daytoday. I use nix-shell to get a build environment. Your change destroys my first use case while providing no benefits.

I understand that this change destroys your first use case. However, there is the benefit that lorri can now be used. AFAIK there is no simple workaround for lorri, but there is a simple workaround for your first use case: Just run

$ nix-build shell.nix
or:
$ nix build -f shell.nix

Note that you have to remove ccache from the build inputs for the Nix build to work. An obvious solution would be to have a separate default.nix for building the derivation. However, non-Nix people might dislike too many .nix files in the repo.

[haslersn]

If it's okay with other maintainers to have two .nix files, then we can have a default.nix for building the derivation and a shell.nix which imports the default.nix with additional native build inputs [ ccache gdb git-clang-format shell-configure shell-build shell-run shell-debug ].

[haslersn]

@poelzi Would this work for you: #2828