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.

See rust-lang/rust#138907

Fixes docs publishing by switching to the new feature merged in rust-lang/rust#138907

Nightly feature doc_auto_cfg is merged into doc_cfg rust-lang/rust#138907

More information: rust-lang/rust#138907

* Update CHANGELOG.md * Update flake.nix File copy from bevy_tween at e6c30ca44213b4a7867925e722838c68edf24fa0 * nix flake update * cargo update * Change doc_auto_cfg to doc_cfg since rust-lang/rust#138907 * Update CHANGELOG.md * Bump version to 0.5.2 * cargo update

Move doc_cfg-specific code into `cfg.rs` Follow-up of rust-lang/rust#138907. r? lolbinarycat

* give name to closure variable types to prevent future confusion * Update CHANGELOG.md * Seperate rust package from buildInputs into stableRust * Add docrs devshell with nightly Rust * nix flake update * Update devshell stableRust to 1.90.0 * Update bevy_time_runner to 0.5.2 * Change doc_auto_cfg to doc_cfg since rust-lang/rust#138907 * Update unreleased changes section in CHANGELOG.md * fix import in docs * update EguiPlugin in bevy_lookup_curve --------- Co-authored-by: Multirious <[email protected]>

See also rust-lang/rust#138907 Signed-off-by: tison <[email protected]>

See rust-lang/rust#138907, also see [#linebender > Cargo doc failures in linebender repos](https://xi.zulipchat.com/#narrow/channel/419691-linebender/topic/Cargo.20doc.20failures.20in.20linebender.20repos/with/542106544).

the `doc_auto_cfg` feature has been merged into `doc_cfg` [1], and this is breaking building vm-memory documentation on docs.rs [2]. [1]: rust-lang/rust#138907 [2]: https://docs.rs/crate/vm-memory/0.17.0/builds/2564760 Signed-off-by: Patrick Roy <[email protected]>

#4331) ## Motivation and Context   Our docrs builds started [failing](https://docs.rs/crate/aws-sdk-dynamodb/1.94.0/builds/2555063) recently with the error: ``` [INFO] [stderr] Documenting aws-sdk-dynamodb v1.94.0 (/opt/rustwide/workdir) [INFO] [stderr] error[E0557]: feature has been removed [INFO] [stderr] --> src/lib.rs:21:29 [INFO] [stderr] | [INFO] [stderr] 21 | #![cfg_attr(docsrs, feature(doc_auto_cfg))] [INFO] [stderr] | ^^^^^^^^^^^^ feature has been removed [INFO] [stderr] | [INFO] [stderr] = note: removed in CURRENT_RUSTC_VERSION; 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 `aws-sdk-dynamodb` ``` The [linked issue](rust-lang/rust#138907) shows that `doc_auto_cfg` has recently been merged into `doc_cfg`. docsrs builds with the latest nightly toolchain, so the change has impacted our doc builds. This PR makes that change in codegen and in all of our runtime crates. ## Checklist  - [ ] For changes to the smithy-rs codegen or runtime crates, I have created a changelog entry Markdown file in the `.changelog` directory, specifying "client," "server," or both in the `applies_to` key. - [ ] For changes to the AWS SDK, generated SDK code, or SDK runtime crates, I have created a changelog entry Markdown file in the `.changelog` directory, specifying "aws-sdk-rust" in the `applies_to` key. ---- _By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice._