:wave: Hi, I'm not sure if I'm doing something dum...

# kotlin-native

[bendb]

👋
Hi, I'm not sure if I'm doing something dumb, or if I've hit a kotlin-native "bug" (for some value of the word "bug"). Basically, I'm attempting to use Apple's Network.framework and hitting seemingly-unavoidable runtime exceptions from the kotlin<>objc interop layer. Specifically, common functions like nw_connection_send and nw_connection_receive take block arguments that return void. The Kotlin compiler will happily accept a function literal:

nw_connection_send(conn, data, NW_CONNECTION_DEFAULT_MESSAGE_CONTEXT, false) { networkError -> ... }

but at runtime, this blows up pretty spectacularly:

2023-09-20 20:39:39.221 test.kexe[91736:4026442] *** Terminating app due to uncaught exception 'NSGenericException', reason: 'Converting Obj-C blocks with non-reference-typed return value to kotlin.Any is not supported (v)'
*** First throw call stack:
(
        0   CoreFoundation                      0x000000010cdd178b __exceptionPreprocess + 242
        1   libobjc.A.dylib                     0x000000010b8ebb73 objc_exception_throw + 48
        2   CoreFoundation                      0x000000010cdd1669 -[NSException initWithCoder:] + 0
        3   test.kexe                           0x0000000102e84647 _ZL16blockToKotlinImpP11objc_objectP13objc_selectorPP9ObjHeader + 679
        4   test.kexe                           0x0000000102eb373d Kotlin_Interop_refFromObjC + 61
        5   test.kexe                           0x0000000102e56599 kfun:com.bendb.repro.NwSocket#write(kotlin.ByteArray;kotlin.Int;kotlin.Int){} + 1993
// so on, so forth

Is this business-as-usual? It seems weird that such a prominent framework, and such a common Apple API style, would be unsupported like this.

[bendb]

I filed a bug for this, on the off chance that this actually is a bug: https://youtrack.jetbrains.com/issue/KT-62102/Runtime-error-calling-Network.framework-fu[…]ks-with-non-reference-typed-return-value-to-kotlin.Any-is