Inline type defining macros, avoid use of cbindgen parse.expand + nightly #610
Conversation
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
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.
ctz
reviewed
Sep 29, 2025
Member
Author
|
Closing in favour of #618 |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
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Outdated suggestions cannot be applied.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.
We have a small collection of
macro_rules!macros that define types: one helper making a u32rustls_resultenum, and a handful for defining opaque structs implementingCastable.These are handy, but they require we use
cbindgen'sparse.expandfunctionality. This in turn requires the nightly toolchain to allowcbindgento expand the macro definitions before generating the.hfile. This worked OK for a while, but nightly broke the handling ofcfgfeature guards way back in April, requiring that contributors + CI both pin tonightly-2025-03-25.Since the bug I opened upstream (rust-lang/rust#139715) hasn't received any significant attention in months let's stop using macros in this context so we can go back to
cbindgenwithoutparse.expandand the stable toolchain. We can't stay pinned tonightly-2025-03-25forever.