Show a warning if ObjCBindingLibrary is used, recommend NativeReference instead

[rolfbjarne]

From @AlphaNERD- on Thu, 21 Mar 2024 11:39:41 GMT

Hello .NET MAUI devs,

like many other devs i am migrating to .NET 8. I am working with a few native SDKs for Android and iOS respectively and i ran into a few binding problems which are close to be fixed.

During my ordeal i made what turned out to be a mistake and tried to bind every SDK using ObjCBindingNativeLibrary, thus introducing a build error involving clang++. I tried to bind some SDKs using ObjCBindingNativeLibrary and others using NativeReference and while i could push the build errors aside, i could not actually use the SDK i bound using ObjCBindingNativeLibrary during runtime.

Now i've bound every SDK again using NativeReference and while i'm still dealing with build errors (duplicate symbols, a potential regression in my specific case compared to Xamarin.iOS) i would like to know the following:

What is the difference between NativeReference and ObjCBindingNativeLibrary

If i had to guess it's that ObjCBindingNativeLibrary is some internal thing. I've seen a few people use in the Github Issues but none of the devs have actively discouraged the use of it AFAIK. I do know however that NativeReference works better with the SDKs and that Microsoft asks devs to use that to reference SDKs in .NET 8.

Copied from original issue dotnet/maui#21352

[rolfbjarne]

From @drasticactions on Fri, 22 Mar 2024 08:00:28 GMT

I think you want the SDK repo, this is for the MAUI UI project and doesn't maintain that tooling. CC @rolfbjarne

[rolfbjarne]

From @rolfbjarne on Fri, 22 Mar 2024 08:29:35 GMT

ObjCBindingNativeLibrary is an item that was introduced quite a few years ago, and is only used for embedding libraries in binding projects.

NativeReference is a newer item, with many more capabilities, and can be used both in a binding project and an app project.

The recommendation is to never use ObjCBindingNativeLibrary, only NativeReference.

[rolfbjarne]

From @AlphaNERD- on Fri, 22 Mar 2024 08:50:49 GMT

Could we mark ObjCBindingNativeLibrary as deprecated, obsolete or otherwise give a compiler warning then?

Funnily enough, i was binding a library using ObjCBindingNativeLibrary and i could not use the library at all. When i tried to create an object instance of the SDK, i got an exception stating that the library could not be loaded. If ObjCBindingNativeLibrary is not about to be removed then i could share a sample project showcasing the problem. I'll have to ask for permmision though from Fujitsu.

[rolfbjarne]

From @rolfbjarne on Fri, 22 Mar 2024 09:12:47 GMT

Could we mark ObjCBindingNativeLibrary as deprecated, obsolete or otherwise give a compiler warning then?

Yes, we could issue a warning if ObjCBindingNativeLibrary is used, so I'm moving this to the xamarin/xamarin-macios repository to track this.