Nixpkgs: Meson overrides compiler, ignoring stdenv

[jtojnar]

When I build a meson package (e.g. gnome-builder) with changed stdenv (e.g to gcc8Stdenv) it still builds with the compiler used by Meson:

https://github.com/NixOS/nixpkgs/blob/7c337cc807f2618e5f162a647e974cffcda86122/pkgs/development/tools/build-managers/meson/default.nix#L60

cc @Ericson2314

[matthewbauer]

That should only be used when cross compiling. It's maybe this line that we need to fix:

https://github.com/NixOS/nixpkgs/blob/7c337cc807f2618e5f162a647e974cffcda86122/pkgs/development/tools/build-managers/meson/setup-hook.sh#L27

[Ericson2314]

Yeah the stuff we do is just problems waiting to happen. I feel like I'm getting pretty close to making MESON use the env vars normally so we can just drop all that. :crossed_fingers::crossed_fingers::crossed_fingers:

[matthewbauer]

Can't we drop it now? CC and CXX should be set by stdenv right? I also have a commit to work on cross meson: https://github.com/matthewbauer/nixpkgs/commit/ea4ec78855e41ceceb7612f8af803eb7d1a6aeda but have not had to time to open a pr for it.

[nh2]

Can't we drop it now?

Let's do it, I also just ran into this again: #80598

[nh2]

Wait in #59041 you decided to not do it?

If this needs an upstream fix we should do it, this totally breaks reasonable behaviour.

[vcunat]

I feel like I'm getting pretty close to making MESON use the env vars normally so we can just drop all that.

@Ericson2314: can you provide a link or something? I don't think I understand what you referred to.

[jtojnar]

I believe that referred to https://github.com/mesonbuild/meson/issues/3969

[Ericson2314]

Yes please make some noise in https://github.com/mesonbuild/meson/pull/6363, which I finally made to fix the issue @jtojnar linked (thanks for fishing it up!). I think it would be more persuasive if someone other than me explains the issue or it's ramifications, as I've sort of made my case to Jussi and the other main meson devs.

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[Ericson2314]

https://github.com/mesonbuild/meson/pull/6363 was merged a few months ago, this issue has finally been resolved!

[wentasah]

I don't think the issue is gone. I experience the problem even with current unstable channel. I work around it by using an overridden meson:

meson.overrideAttrs (attrs: { depsHostHostPropagated = [ ]; })

but it probably won't work for everybody.

See
https://github.com/NixOS/nixpkgs/blob/bf007a2c0a8c60c4c552c3213b4f095de928ee23/pkgs/development/tools/build-managers/meson/default.nix#L66-L68

[Ericson2314]

I suppose that would get more in the way without strictDeps, but with strictDeps it only effect CC_FOR_BUILD.

https://github.com/mesonbuild/meson/pull/6512 just got merged, so we can remove the hack next release!

[leotaku]

@Ericson2314 Is removing the below workaround the only thing that needs to be done now? Or will individual package expressions have to be edited to accommodate this change? If we only need to remove the workaround, maybe someone can create a PR.

https://github.com/NixOS/nixpkgs/blob/703f052de185c3dd1218165e62b105a68e05e15f/pkgs/development/tools/build-managers/meson/default.nix#L66-L68

[Ericson2314]

Just that! Happy to do it, but do we have the new Meson version yet?

[leotaku]

@Ericson2314 From what I can tell, we do have the latest version. #98228

[Ericson2314]

Oh, great!

[vcunat]

But the above meson PR isn't contained in any release yet, it seems.

[Ericson2314]

Oh, right that's a 55.n+1 not 56

[vcunat]

I always click the commit and watch the set of tags (and branches) containing it.

[leotaku]

Sorry, I naively assumed that the PR was already in the 0.55.3 release because it was older than the release date shown on GitHub.