regression: Sign is ambiguous

[BoxyUwU]

• https://crater-reports.s3.amazonaws.com/beta-1.85-1/beta-2025-01-12/reg/crypt_guard-1.3.7/log.txt

[INFO] [stdout] error[E0659]: `Sign` is ambiguous
[INFO] [stdout]    --> src/Core/cipher_aes_gcm_siv.rs:114:24
[INFO] [stdout]     |
[INFO] [stdout] 114 |         let mut hmac = Sign::new(plaintext.to_vec(), passphrase, Operation::Sign, SignType::Sha512);
[INFO] [stdout]     |                        ^^^^ ambiguous name
[INFO] [stdout]     |
[INFO] [stdout]     = note: ambiguous because of multiple glob imports of a name in the same module

note: there were some other (knock on?) errors in this crate see logs for more detail

[theemathas]

Presumably regressed in #118159, which added std::fmt::Sign as an unstable type.

[apiraino]

WG-prioritization assigning priority (Zulip discussion).

@rustbot label -I-prioritize +P-high

[theemathas]

As it turns out, glob imports have been causing unstable items to affect stable code for a long time now. For example, the following code has been failing to compile since version 1.1.0, when std::ops::CoercedUnsized was added as an unstable trait.

use foo::*;
use std::ops::*;

mod foo {
    pub struct CoerceUnsized;
}

fn main() {
    let x: CoerceUnsized;
}

[Noratrieb]

This is the crate: https://crates.io/crates/crypt_guard

Not that many downloads (but also not none). Looks maintained so they would probably make a fix release when we tell them. Not on the team, but I'd lean towards accepting the breakage, just the usual glob import brittleness.

[Amanieu]

We discussed this in the libs-api team and decided that this is acceptable breakage as per our policy with glob imports. The crate author should still be notified about the upcoming breaking change via an issue.

Additionally, we think that the lint proposed by @tgross35 in rust-lang/rust-clippy#13961 should be a built-in lint. You almost never want to glob import from the standard library except for a few prelude modules.

[Noratrieb]

I've notified them in mm9942/crypt_guard#9

[mm9942]

Thanks for the infos! I'll look it up soon and update the crate.