clippy: don't print warnings/errors about subprojects

[1ace]

That code is not under the control of the developer asking for this information, so this is pure spam; simply skip it :)

[bonzini]

That can be handled by passing --cap-lints allow to rustc in.the subproject; ninja clippy then automatically skips that subproject.

Entirely disabling clippy for subprojects doesn't work as well because sometimes subprojects are part of the project but separate for organizational reasons.

[1ace]

I started adding rust_args: ['--cap-lints', 'allow'] to all the subprojects and it looks like it works, but the problem is that not all subprojects' meson.build are checked into the top-level project, in which case your suggestion is not possible. That's actually the case in Mesa, which is what I'm working on and the reason I'm here.

I didn't think about the case of subprojects that are actually part of the same project though; it feels weird but it probably exists, so I understand that my suggestion is not good. Is there a way in meson to tell apart a subproject that's external from a subproject that's internal?

[1ace]

Oh sorry, I was confused by the subprojects not getting automatically reconfigured, it actually looks like it's all good. I'm going to close this PR, but in the end we're not going to go with your suggestion but warning_level=0 that a colleague of mine suggested in parallel: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38814

Anyway, thank you for your help @bonzini 🙏

[LingMan]

To be fair, I picked up the warning_level=0 from here a few days ago. So it was his suggestion after all 😆

[LingMan]

(Although the part that subprojects don't pick up changes to their meson.build automatically threw me off at first, too. That should really be changed.)