error: use decl+proc macro to generate u32 mapping #618
Merged
Conversation
We only used this for `rustls_result`, and in practice it only saved us having to implement `From<u32>` by hand. That's handy, but comes at the cost of needing to use the nightly toolchain w/ cbindgen so it can expand the macro before generating the `.h`. That wasn't the worst, but a nighty regression that has remained unfixed for months broke this workflow. In sum: life will be easier without the macro. RIP.
They're helpful, but require us to use cbindgen's parse.expand feature which in turn requires nightly, and is broken with nightly since ~April.
Since we have no macros anymore, it's not needed.
This works because cbindgen does not need to expand derive macros to see the enum items, and cbindgen does not care about the existence of `impl From<u32>` for the rust type that the derive outputs.
djc
approved these changes
Oct 27, 2025
Member
djc
left a comment
There was a problem hiding this comment.
I don't love it, but I certainly won't object to it.
cpu
approved these changes
Oct 27, 2025
Member
cpu
left a comment
There was a problem hiding this comment.
Seems like a good compromise 👍 Thanks!
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
This works because cbindgen does not need to expand derive macros to see the enum items, and cbindgen does not care about the existence of
impl From<u32>for the rust type that the derive outputs.On top of #610