What is the reason that `typedef struct Foo Foo;` winds up as `cnames.structs.Foo` whereas `typedef ...

# kotlin-native

[jw]

What is the reason that typedef struct Foo Foo; winds up as cnames.structs.Foo whereas typedef struct Foo { ... } Foo; goes into my.package.Foo? I'm running into simple name collisions in cnames.structs which are causing compilation failures only on some native targets.

[sergey.bogolepov]

cnames.structs is used to support forward declarations in Kotlin. More precisely, to support cases like "forward declaration (typedef struct Foo Foo;) gets into module A, and an actual declaration (typedef struct Foo { ... } Foo;) gets into module B". If both modules get into the compiler, then compiler magically resolves references to cnames.structs.Foo to B.Foo.

Could you share a reproducer?

[sergey.bogolepov]

I assumed that you're talking about https://kotlinlang.slack.com/archives/C3SGXARS6/p1632238934261200, checked and created a ticket.

[sergey.bogolepov]

One possible workaround is add a "real" struct declaration to the def file. Something like this:

---
typedef struct Foo {} Foo;

It will force cinterop to use my.package.Foo instead of cnames.structs.Foo. Does it work for you?

[msink]

It does "magically" work in single target build, but does not work in HMPP after commonizer:

[msink]

https://youtrack.jetbrains.com/issue/KT-46636

[msink]

And magic does not work in tools like Dokka:
https://github.com/Kotlin/dokka/issues/1992

[jw]

Does it work for you?

Yes. Thanks! This is much better.