Zerocopy 0.8.32 breaks combined with `deny(non_ascii_idents)`

[kristof-mattei]

For security reasons we cannot allow non-ascii-identifiers in our codebase, and as such we apply #![deny(non_ascii_idents)].

However, since upgrading to Zerocopy 0.8.32 (0.8.33 has same behavior) we are running into violations of the non_ascii_idents lint.

src/main.rs:

#![deny(non_ascii_idents)]

use zerocopy::{FromBytes, Immutable, IntoBytes, KnownLayout};

#[derive(KnownLayout, FromBytes, IntoBytes, Immutable)]
#[repr(C)]
pub struct ifaddrmsg {
    pub ifa_family: u8,    /* Address type */
    pub ifa_prefixlen: u8, /* Prefixlength of address */
    pub ifa_flags: u8,     /* Address flags */
    pub ifa_scope: u8,     /* Address scope */
    pub ifa_index: u32,    /* Interface index */
}

fn main() {}

Cargo.toml:

[package]
name = "zerocopy-non-ascii-error"
version = "0.1.0"
edition = "2024"

[dependencies]
zerocopy = { version = "0.8.33", features = ["derive"] }

bash:

❯ cargo run
   Compiling zerocopy-non-ascii-error v0.1.0 (/home/kristof/projects/zerocopy-non-ascii-error)
error: identifier contains non-ASCII characters
 --> src/main.rs:8:9
  |
8 |     pub ifa_family: u8,    /* Address type */
  |         ^^^^^^^^^^
  |
note: the lint level is defined here
 --> src/main.rs:1:9
  |
1 | #![deny(non_ascii_idents)]
  |         ^^^^^^^^^^^^^^^^

error: identifier contains non-ASCII characters
 --> src/main.rs:9:9
  |
9 |     pub ifa_prefixlen: u8, /* Prefixlength of address */
  |         ^^^^^^^^^^^^^

error: identifier contains non-ASCII characters
  --> src/main.rs:10:9
   |
10 |     pub ifa_flags: u8,     /* Address flags */
   |         ^^^^^^^^^

error: identifier contains non-ASCII characters
  --> src/main.rs:11:9
   |
11 |     pub ifa_scope: u8,     /* Address scope */
   |         ^^^^^^^^^

error: identifier contains non-ASCII characters
  --> src/main.rs:12:9
   |
12 |     pub ifa_index: u32,    /* Interface index */
   |         ^^^^^^^^^

error: could not compile `zerocopy-non-ascii-error` (bin "zerocopy-non-ascii-error") due to 5 previous errors

Traced back to this PR: 002b97d#diff-977c29e6cf079bd7307f811df24f99633df603962785c583145eb6250b0e12daR755

There was a comment about it: #2842 (comment) but no mention of non_ascii_idents.

Could an allow be applied to those lines, just like here: 002b97d#diff-977c29e6cf079bd7307f811df24f99633df603962785c583145eb6250b0e12daR782 ?

[joshlf]

Ah thanks for letting us know! Yeah, it should be easy for us to add an allow for this. We'll do that shortly.

[kristof-mattei]

Ah thanks for letting us know! Yeah, it should be easy for us to add an allow for this. We'll do that shortly.

Let me know if you'd like me to test a branch before releasing something.

[jswrenn]

@joshlf Add allows for other ident lints, too, since we can't generally forward local allows from the user's struct definitions.

[joshlf]

It appears as though allow'ing the lint isn't feasible due to a restriction from Rust that the lint is ignored if it's not used at the crate level.

[joshlf]

I'd like to wait a bit to see if we can get rust-lang/rust#151025 resolved before consider other approaches (the most obvious one being to stop using non-ASCII identifiers internally).