Rust

6130 readers

51 users here now

Welcome to the Rust community! This is a place to discuss about the Rust programming language.

Wormhole

[email protected]

Credits

The icon is a modified version of the official rust logo (changing the colors to a gradient and black background)

founded 2 years ago

MODERATORS

[email protected]

Semver violations are common, better tooling is the answer (predr.ag)

submitted 1 year ago by [email protected] to c/[email protected]

23 comments fedilink hide all child comments

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 5 points 1 year ago (3 children)

What do you think #[doc(hidden)] is for, other than declaring something "private" that the language unfortunately doesn't let you declare as truly private right now?

I've mostly seen it used as a way to expose tools to macro APIs. For example, these internal parts of the quote! macro, or these internal parts of the vec! macro. Changing these things shouldn't be considered a semver violation, because they're not really part of the API, even though the quote! macro can't enforce it.

The only other cases I can think of where I've seen #[doc(hidden)] used are even bigger kludges, and the hidden items definitely aren't part of the platonic API, like pre-#[non_exhaustive] crates that wanted to reserve the right to add new variants to their enums.

[–] [email protected] 5 points 1 year ago

It would be nice if we had something like pub(macro), which would make something public but only inside macros from the same crate. So they are usable in macros but not part of the public API.

[–] [email protected] 1 points 1 year ago

Probably a spicy take, but I think any API being used by a macro should be made public. A macro shouldn't be the only way to do something; it should just be a way to remove the boilerplate required to do it.

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago) (1 children)

I'm arguing (humbly of course) that intended vs. unintended use of what is at the end of the day a part of the public interface shouldn't be taken into consideration by default. Otherwise, other cases can be argued as non-breaking too!

Foo was never meant to be sent to other threads, So, losing Send is not a semver- breaking change!

Exhaustive enum Bar is only meant to be matched exhaustively internally. We say so in the docs. So adding a variant to it is not a semver-breaking change!

And giving more powers to a (kludge) doc attribute just doesn't seem in my eyes to be a generally wise move.

A: cargo-semver is still complaining about this item which I already have cfg-ed under an exp_api crate feature (which I don't want to rename). CI is failing.

B: PRO-TIP: Just slap a #[doc(hidden)] on it and CI will pass!

A: What if I still want to see the docs?

B: We are pushing for --document-hidden-items to stabilize soon. So you can just simply use that!

[–] [email protected] 1 points 1 year ago

That's a good point.

cargo-semver-check should definitely provide a way to mark syntactically-public items as "de-facto private," because some projects just need to do bad things and leaving them out in the cold is not helpful. But you've convinced me that doc(hidden) is a poor way to do it.