Proposal: Allow 3-digit-grouped binary in non_octal_unix_permissions

[SabrinaJewson]

Description

I personally much prefer to write Unix permissions in binary rather than octal. For comparison:

Format	Representation
ls(1)	rwxr-xr--
Binary	0b111_101_100
Octal	0o754
chmod(1)	ugo+rwx,go-w,o-x or u+rwx,g+rx-w,o+r-wx

The 3-group binary format is more readable than octal in my opinion, because it lines up very neatly with the ls(1) rwxrwxrwx format, and does not require any binary conversion or lookup tables in one’s head.

Currently Clippy disallows the following code:

fn main() {
    std::fs::Permissions::from_mode(0b111_101_100);
}
use std::os::unix::prelude::PermissionsExt as _;

To support this pattern, Clippy should include an exception in the non_octal_unix_permissions and unusual_byte_groupings lints, to specifically allow binary literals of the exact format 0b[XXX_]XXX_XXX_XXX.

Version

rustc 1.71.0 (8ede3aae2 2023-07-12)
binary: rustc
commit-hash: 8ede3aae28fe6e4d52b38157d7bfe0d3bceef225
commit-date: 2023-07-12
host: x86_64-unknown-linux-gnu
release: 1.71.0
LLVM version: 16.0.5

Additional Labels

@rustbot label +C-enhancement

[Alexendoo]

It would be reasonable to plain allow binary literals in general

[Centri3]

I agree, in the case of bitflags of any kind it's much easier to understand using binary

[cocodery]

@rustbot claim