[AppKit] ApplicationIconImage and NSDockTile.ContentView reject valid null values

[tipa]

Apple platform

macOS

Framework version

net10.0-*

Affected platform version

macOS 26.6.1 arm64; Xcode 26.6; .NET SDK 10.0.302; macOS workload 26.5.10301.

Description

NSApplication.ApplicationIconImage and NSDockTile.ContentView throw ArgumentNullException when assigned null.

AppKit declares applicationIconImage as null_resettable and contentView as nullable. The generated .NET setters instead call GetNonNullHandle, preventing the documented reset operations.

Expected: forward nil to AppKit.
Actual: throw before calling AppKit.

Binding definitions:

• https://github.com/dotnet/macios/blob/d259b5ff3c50ae17c72b0110a4c3c37f7926a108/src/appkit.cs#L813-L814
• https://github.com/dotnet/macios/blob/d259b5ff3c50ae17c72b0110a4c3c37f7926a108/src/appkit.cs#L6592-L6593

Steps to Reproduce

1. Create a net10.0-macos app.
2. Run each statement separately:

NSApplication.SharedApplication.ApplicationIconImage = null!;
NSApplication.SharedApplication.DockTile.ContentView = null!;

3. Each setter throws ArgumentNullException from GetNonNullHandle.

Did you find any workaround?

A correctly typed objc_msgSend call can forward nil:

[DllImport("/usr/lib/libobjc.A.dylib", EntryPoint = "objc_msgSend")]
static extern void SendVoid(IntPtr receiver, IntPtr selector, IntPtr value);

SendVoid((IntPtr)receiver.Handle, Selector.GetHandle(setterName), IntPtr.Zero);

Relevant logs

No response

[rolfbjarne]

Confirmed; a fix is in progress.

Thanks for the report!