tidy complains about valid stability attribute

[RalfJung]

With the following stability attribute

    #[unstable(
        feature = "internal_uninit_const",
        issue = "0",
        reason = "hack to work around promotability",
    )]

tidy complained

tidy error: /checkout/src/libcore/mem/maybe_uninit.rs:256: malformed stability attribute: missing `feature` key

Seems like it's parser is a bit too simplified.

See #62799 (comment) for the CI failure and f3abbf7 for the work-around.

[varkor]

The parsing is very simplistic:

rust/src/tools/tidy/src/features.rs

Lines 436 to 446 in 83dfe7b

	let level = if line.contains("[unstable(") {
	Status::Unstable
	} else if line.contains("[stable(") {
	Status::Stable
	} else {
	continue;
	};
	let feature_name = match find_attr_val(line, "feature") {
	Some(name) => name,
	None => err!("malformed stability attribute: missing `feature` key"),
	};

[RalfJung]

Can't we just make rustc complain about malformed stable/unstable attributes? What is the reason why tidy has to check this?

[petrochenkov]

@RalfJung
rustc already complains about missing features and other ill-formed stability attributes.
Tidy wants to collect those features to complain about something else, first of all (e.g. about a feature not having a dedicated test etc.).

[Mark-Simulacrum]

I'm going to close this as won't fix. Expanding tidy into a full fledged parser is something I'd like to avoid as much as possible, and this seems like something that's fairly easy to work around. Maybe we could refile on rustc-guide or similar as a "here's a hint that this error might be buggy" and associate how to fix it, not sure.