rwlock tests: fix miri macos test regression

[RalfJung]

#144648 broke the attributes that ignore the tests on Miri; this patch should fix that.

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[RalfJung]

This just fixes the Miri cases; there are more cfg_attr(..., ignore) attached to nonpoison_and_poison_unwrap_test! and none of those actually work (the attribute ends up attached to the first test only).

Cc @connortsui20 ; would be good if you could fix the rest of them.

[tgross35]

@bors r+ rollup

[bors]

📌 Commit 0928026 has been approved by tgross35

It is now in the queue for this repository.

[connortsui20]

@RalfJung sure! Could you tell me why the cfg_attr is different from cfg(not()) here?

[RalfJung]

Note that it's cfg_attr($cond, ignore) vs cfg(not($cond)). See the cfg_attr docs for details.

But it is true that I just assumed that the cfg would be expanded early and disable the the entire macro invocation, which may or may not be true... I'll have to test that.

[connortsui20]

Ah I see, the #[ignore] only gets passed down to the first test.

https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute
https://doc.rust-lang.org/reference/attributes/testing.html#the-ignore-attribute

Is it worth refactoring the macro so that it can apply any attribute macros to both? That's almost certainly going to cause confusion in the future. Though I don't really know how I would implement that to be honest...

[RalfJung]

cfg indeed does get applied before the macro is expanded apparently, so both tests get disabled.

Is it worth refactoring the macro so that it can apply any attribute macros to both? That's almost certainly going to cause confusion in the future. Though I don't really know how I would implement that to be honest...

Yeah you could have something like

nonpoison_and_poison_unwrap_test!(
    name: frob,
    test_body:
    #[attr1]
    #[attr2]
    {

Using the meta macro matcher, that should not be too hard to implement.