Implement RFC 3631: add rustdoc doc_cfg features #138907

GuillaumeGomez · 2025-03-24T22:50:33Z

This implementation actually resulted in a lot of simplifications:

All cfg computation is now done in one place: propagate_doc_cfg.rs. Because (trait) impls are not retrieved at the same time as the other items, we cannot perform this computation in the clean process, it needs to be after.
Because there is cfg inheritance, we can keep track of them in one place (in propagate_doc_cfg.rs), meaning we don't need to copy an item's attributes to its children anymore. Only exception: impl items. For them we clone only cfg attributes.
propagate_doc_cfg.rs is also now much simpler, much less need to keep track of parents, since everything we need is handled by the new CfgInfo type.
I also suspect that Cfg::simplify_with could either be removed or at least used directly into propagate_doc_cfg.rs when we compute cfgs. Considering how big the PR already is, I'll do it in a follow-up.

I didn't remove the doc_cfg* features in this PR because some dependencies used in rustc (like stdarch) are using it, so we need to have a nightly released with this PR before I can switch to the new feature.

r? ghost

petrochenkov · 2025-03-25T09:48:06Z

What remains to be done:

I'd also want to block the stabilization on landing #138844 to avoid a stable rustdoc feature relying on externally observable hacks in rustc.
The crater run in #138844 returned mostly clean, so I expect it to land soon.

GuillaumeGomez · 2025-03-25T10:36:45Z

Noted! And that will be a nice improvement, thanks!

Just one thing left for the cfg expansion missing: #[cfg_attr(blabla, derive(Debug))]. In this case, the cfg is not kept in the generated derive items. It's been in my TODO list for a long time now. ^^'

petrochenkov · 2025-03-25T10:49:31Z

Just one thing left for the cfg expansion missing: #[cfg_attr(blabla, derive(Debug))]

Do you mean like in #138515? :)

GuillaumeGomez · 2025-03-25T10:52:03Z

You're my hero! Gonna need to handle this new attribute then. :)

bors · 2025-03-25T17:53:10Z

☔ The latest upstream changes (presumably #138923) made this pull request unmergeable. Please resolve the merge conflicts.

bors · 2025-03-27T19:41:02Z

☔ The latest upstream changes (presumably #138927) made this pull request unmergeable. Please resolve the merge conflicts.

The `doc_auto_cfg` feature was removed in Rust 1.92.0 and merged into `doc_cfg` (see rust-lang/rust#138907). This fixes the docs.rs build failure for clawspec-core. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

The `doc_auto_cfg` feature was removed in Rust 1.92.0 and merged into `doc_cfg` (see rust-lang/rust#138907). This fixes the docs.rs build failure for clawspec-core. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Fix removed version numbers of `doc_auto_cfg` and `doc_cfg_hide` Tracking issue: rust-lang/rust#43781 The `doc_auto_cfg` and `doc_cfg_hide` features were removed in a recent nightly (by rust-lang/rust#138907). I believe that the rustc version numbers at which the features were declared to be removed were incorrect, however, and should both be "1.92" (±1). As evidence in favour of this, the error we get from using this was: ```text error[E0557]: feature has been removed --> src/lib.rs:22:29 | 22 | #![cfg_attr(docsrs, feature(doc_auto_cfg))] | ^^^^^^^^^^^^ feature has been removed | = note: removed in 1.58.0; see <rust-lang/rust#138907> for more information = note: merged into `doc_cfg` ``` Note especially the "removed in 1.58" claim. Further evidence is found in the comment further up this file: https://github.com/rust-lang/rust/blob/4ffeda10e10d4fa0c8edbd0dd9642d8ae7d3e66e/compiler/rustc_feature/src/removed.rs#L49-L53 I've chosen 1.92 as that was the milestone which rust-lang/rust#138907 was added to. cc `@GuillaumeGomez`

error[E0557]: feature has been removed --> src/lib.rs:42:29 | 42 | #![cfg_attr(docsrs, feature(doc_auto_cfg))] | ^^^^^^^^^^^^ feature has been removed | = note: removed in 1.92.0; see <rust-lang/rust#138907> for more information = note: merged into `doc_cfg` error: Compilation failed, aborting rustdoc

The current documentation build in docs.rs breaks with the following error: [INFO] [stderr] error[E0557]: feature has been removed [INFO] [stderr] --> src/lib.rs:11:29 [INFO] [stderr] | [INFO] [stderr] 11 | #![cfg_attr(docsrs, feature(doc_auto_cfg))] [INFO] [stderr] | ^^^^^^^^^^^^ feature has been removed [INFO] [stderr] | [INFO] [stderr] = note: removed in 1.92.0; see <rust-lang/rust#138907> for more information [INFO] [stderr] = note: merged into `doc_cfg` So replace `doc_auto_cfg` with `doc_cfg`, which generates the expected docs, showing the required features for each module. Signed-off-by: Carlos López <carlos.lopezr4096@gmail.com>

`doc_auto_cfg` has been removed from the current Rust version, which caused rustdoc breakages. See rust-lang/rust#138907

See rust-lang/rust#138907

The doc_auto_cfg feature was incorporated into the doc_cfg feature in rust-lang/rust#138907 Closes ratatui#2102 Signed-off-by: Shingo OKAWA <shingo.okawa.g.h.c@gmail.com>

Fix removed version numbers of `doc_auto_cfg` and `doc_cfg_hide` Tracking issue: rust-lang/rust#43781 The `doc_auto_cfg` and `doc_cfg_hide` features were removed in a recent nightly (by rust-lang/rust#138907). I believe that the rustc version numbers at which the features were declared to be removed were incorrect, however, and should both be "1.92" (±1). As evidence in favour of this, the error we get from using this was: ```text error[E0557]: feature has been removed --> src/lib.rs:22:29 | 22 | #![cfg_attr(docsrs, feature(doc_auto_cfg))] | ^^^^^^^^^^^^ feature has been removed | = note: removed in 1.58.0; see <rust-lang/rust#138907> for more information = note: merged into `doc_cfg` ``` Note especially the "removed in 1.58" claim. Further evidence is found in the comment further up this file: https://github.com/rust-lang/rust/blob/4ffeda10e10d4fa0c8edbd0dd9642d8ae7d3e66e/compiler/rustc_feature/src/removed.rs#L49-L53 I've chosen 1.92 as that was the milestone which rust-lang/rust#138907 was added to. cc `@GuillaumeGomez`

rust-lang/rust#138907

See https://docs.rs/crate/object_store/latest/builds/2752265 : ```text [INFO] [stderr] Documenting object_store v0.13.0 (/opt/rustwide/workdir) [INFO] [stderr] error[E0557]: feature has been removed [INFO] [stderr] --> src/lib.rs:18:29 [INFO] [stderr] | [INFO] [stderr] 18 | #![cfg_attr(docsrs, feature(doc_auto_cfg))] [INFO] [stderr] | ^^^^^^^^^^^^ feature has been removed [INFO] [stderr] | [INFO] [stderr] = note: removed in 1.92.0; see <rust-lang/rust#138907> for more information [INFO] [stderr] = note: merged into `doc_cfg` [INFO] [stderr] [INFO] [stderr] error: Compilation failed, aborting rustdoc [INFO] [stderr] [INFO] [stderr] For more information about this error, try `rustc --explain E0557`. [INFO] [stderr] error: could not document `object_store` ```

See https://docs.rs/crate/object_store/latest/builds/2752265 : ```text [INFO] [stderr] Documenting object_store v0.13.0 (/opt/rustwide/workdir) [INFO] [stderr] error[E0557]: feature has been removed [INFO] [stderr] --> src/lib.rs:18:29 [INFO] [stderr] | [INFO] [stderr] 18 | #![cfg_attr(docsrs, feature(doc_auto_cfg))] [INFO] [stderr] | ^^^^^^^^^^^^ feature has been removed [INFO] [stderr] | [INFO] [stderr] = note: removed in 1.92.0; see <rust-lang/rust#138907> for more information [INFO] [stderr] = note: merged into `doc_cfg` [INFO] [stderr] [INFO] [stderr] error: Compilation failed, aborting rustdoc [INFO] [stderr] [INFO] [stderr] For more information about this error, try `rustc --explain E0557`. [INFO] [stderr] error: could not document `object_store` ``` Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>

## What changes are proposed in this pull request? Noticed docs didn't build successfully for [0.17.0 release](https://docs.rs/crate/delta_kernel/0.17.0/builds/2652981) since in rustc 1.92 the `doc_auto_cfg` feature was removed (and TIL docs.rs builds with nightly). This pr just moves from the `doc_auto_cfg` to `doc_cfg` (see associated [rust pr](rust-lang/rust#138907)). ## How was this change tested? docs only. reproed with `cargo +nightly doc`

See https://docs.rs/crate/object_store/latest/builds/2752265 : ```text [INFO] [stderr] Documenting object_store v0.13.0 (/opt/rustwide/workdir) [INFO] [stderr] error[E0557]: feature has been removed [INFO] [stderr] --> src/lib.rs:18:29 [INFO] [stderr] | [INFO] [stderr] 18 | #![cfg_attr(docsrs, feature(doc_auto_cfg))] [INFO] [stderr] | ^^^^^^^^^^^^ feature has been removed [INFO] [stderr] | [INFO] [stderr] = note: removed in 1.92.0; see <rust-lang/rust#138907> for more information [INFO] [stderr] = note: merged into `doc_cfg` [INFO] [stderr] [INFO] [stderr] error: Compilation failed, aborting rustdoc [INFO] [stderr] [INFO] [stderr] For more information about this error, try `rustc --explain E0557`. [INFO] [stderr] error: could not document `object_store` ``` Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>

See https://docs.rs/crate/object_store/latest/builds/2752265 : ```text [INFO] [stderr] Documenting object_store v0.13.0 (/opt/rustwide/workdir) [INFO] [stderr] error[E0557]: feature has been removed [INFO] [stderr] --> src/lib.rs:18:29 [INFO] [stderr] | [INFO] [stderr] 18 | #![cfg_attr(docsrs, feature(doc_auto_cfg))] [INFO] [stderr] | ^^^^^^^^^^^^ feature has been removed [INFO] [stderr] | [INFO] [stderr] = note: removed in 1.92.0; see <rust-lang/rust#138907> for more information [INFO] [stderr] = note: merged into `doc_cfg` [INFO] [stderr] [INFO] [stderr] error: Compilation failed, aborting rustdoc [INFO] [stderr] [INFO] [stderr] For more information about this error, try `rustc --explain E0557`. [INFO] [stderr] error: could not document `object_store` ``` Co-authored-by: Marco Neumann <marco@crepererum.net>

The current documentation build in docs.rs breaks with the following error: [INFO] [stderr] error[E0557]: feature has been removed [INFO] [stderr] --> src/lib.rs:11:29 [INFO] [stderr] | [INFO] [stderr] 11 | #![cfg_attr(docsrs, feature(doc_auto_cfg))] [INFO] [stderr] | ^^^^^^^^^^^^ feature has been removed [INFO] [stderr] | [INFO] [stderr] = note: removed in 1.92.0; see <rust-lang/rust#138907> for more information [INFO] [stderr] = note: merged into `doc_cfg` So replace `doc_auto_cfg` with `doc_cfg`, which generates the expected docs, showing the required features for each module. Signed-off-by: Carlos López <carlos.lopezr4096@gmail.com>

The nightly feature has been removed in rust 1.92, see docs.rs build failure https://docs.rs/crate/rustls-native-certs/latest/builds/2773223 and rust PR rust-lang/rust#138907.

The nightly feature has been removed in rust 1.92, see docs.rs build failure https://docs.rs/crate/rustls-native-certs/latest/builds/2773223 and rust PR rust-lang/rust#138907. Also, renamed the cfg into `rustls_native_certs_docsrs`. See rustls/rustls#2682 for more info.