Exceptions are not catched

[paxbun]

Version: 0.1.2
Rust version: 1.81.0 (LLVM 18)
Git hash: c86ad3a

objc_exception::r#try(|| {
    let _: () = msg_send![
        input_node,
        installTapOnBus: 0usize
        bufferSize: (input_num_samples_per_second / 10.0) as u32
        format: input_format
        block: &*block
    ];
})
.map_err(|error| Error::Other(Box::new(NSError(StrongPtr::new(error as *mut Object)))))

Stacktrace (Firebase Crashlytics):

We're using this library to catch Objective-C exceptions on iOS, but for some reason, RustObjCExceptionTryCatch can't catch the exception thrown from the Rust lambda. AFAIK, Rust's panic unwinding and Objective-C's exception are both based on the Itanium C++ ABI, but I don't know the details.

[paxbun]

This is the only part in our codebase that (directly or indirectly) uses objc_exception; I've just replaced this with a real Objective-C source code linked with the cc crate. I'll leave some notes here after updating the app.

[madsmtm]

The problem is likely the use of extern "C" (in both block and objc-exception), if extern "C-unwind" was used, it'd allow the Rust exception to propagate.

(FYI, the crates I maintain, block2 and objc2 have resolved these problems).

[paxbun]

@madsmtm Thanks for the information! Time to do some migration then...