Doc feature banners won't show up when re-exporting items with wildcard

[rodrigocfd]

Problem

I'm building a big library crate, composed of multiple sub-crates. These sub-crates are gated through Cargo features, so the user can choose what to import.

My goal is to have "fruits" and "colors" feature banners in the docs, for each item, like this:

However, I'm only achieving this by manually declaring each member of each sub-crate:

#[cfg(feature = "colors")]
pub use colors::{
    blue,
    red,
    white,
};

#[cfg(feature = "fruits")]
pub use fruits::{
    banana,
    grape,
};

There will be hundreds of declarations, so this is very error-prone. When using wildcards to the declare the members, the feature banners won't show up:

#[cfg(feature = "colors")]
pub use colors::*;

#[cfg(feature = "fruits")]
pub use fruits::*;

Is this a bug or am I missing something?

Minimal reproducible example:

• https://github.com/rodrigocfd/big-lib

Steps

1. Generate the docs with:

RUSTDOCFLAGS="--cfg docsrs" cargo +nightly doc --all-features --no-deps -p big-lib

Possible Solution(s)

No response

Notes

No response

Version

cargo 1.71.0 (cfd3bbd8f 2023-06-08)
release: 1.71.0
commit-hash: cfd3bbd8fe4fd92074dfad04b7eb9a923646839f
commit-date: 2023-06-08
host: x86_64-pc-windows-msvc
libgit2: 1.6.4 (sys:0.17.1 vendored)
libcurl: 8.0.1-DEV (sys:0.4.61+curl-8.0.1 vendored ssl:Schannel)
os: Windows 10.0.19045 (Windows 10 Pro) [64-bit]

[ehuss]

Transferred to rust-lang/rust, since this is likely an issue for rustdoc, which is tracked here.

[GuillaumeGomez]

I confirm this is a bug. Working on a fix.

[GuillaumeGomez]

One question though. Why did you put both cfg and cfg_attr for the same cfg:

#[cfg(feature = "colors")]
#[cfg_attr(docsrs, cfg(feature = "colors"))]
pub use colors::*;

Unless I'm missing something, it's supposed to be exactly the same so with --cfg docsrs you will have cfg(feature = "colors") twice.

[rodrigocfd]

One question though. Why did you put both cfg and cfg_attr for the same cfg

You're right, it's redundant. It's a leftover from all the combinations I tried (I really tried everything possible).

Fixed.