WKUIDelegate runJavaScriptTextInputPanelWithPrompt has incorrect nullability

[mattleibow]

The API in objc (and also in the ms docs) indicate that values can be null:

https://developer.apple.com/documentation/webkit/wkuidelegate/1538086-webview?language=objc

 public virtual void RunJavaScriptTextInputPanel (
     WebKit.WKWebView webView,
     string prompt,
-    string defaultText,
+    string defaultText?,
     WebKit.WKFrameInfo frame,
-    Action<string> completionHandler);
+    Action<string?> completionHandler);

[chamons]

I assume this would be covered by your nullability work, have you looked at this framework yet @tj-devel709 ?

[OMendozaG]

this bug come from far with xamarin.. please solve this...

[xperseguers]

Any news on this? It looks like with MAUI and .NET v8 (at least) the problem is still present.

[rolfbjarne]

Can you try using this as a workaround, it's a custom implementation of the runJavaScriptTextInputPanelWithPrompt selector:

using CoreFoundation;
using ObjCRuntime;
using WebKit;
#nullable enable

class MyWKUIDelegate : WKUIDelegate {
	// Custom implementation due to https://github.com/xamarin/xamarin-macios/issues/15728.
	[Export ("webView:runJavaScriptTextInputPanelWithPrompt:defaultText:initiatedByFrame:completionHandler:")]
	void RunJavaScriptTextInputPanel (WKWebView webView, string prompt, string? defaultText, WKFrameInfo frame, IntPtr blockCompletionHandler)
	{
		var completionHandler = NIDActionArity1V72.Create (blockCompletionHandler);

		// ...
		if (completionHandler is not null)
			completionHandler (null);
	}

	sealed class NIDActionArity1V72 : TrampolineBlockBase {
		[UnmanagedFunctionPointerAttribute (CallingConvention.Cdecl)]
		[UserDelegateType (typeof (global::System.Action<string?>))]
		unsafe delegate void DActionArity1V72 (IntPtr block, NativeHandle obj);

		DActionArity1V72 invoker;
		public unsafe NIDActionArity1V72 (BlockLiteral *block) : base (block)
		{
			invoker = block->GetDelegateForBlock<DActionArity1V72> ();
		}
		[Preserve (Conditional=true)]
		public unsafe static global::System.Action<string?>? Create (IntPtr block)
		{
			if (block == IntPtr.Zero)
				return null;
			var del = (global::System.Action<string?>) GetExistingManagedDelegate (block);
			return del ?? new NIDActionArity1V72 ((BlockLiteral *) block).Invoke;
		}
		unsafe void Invoke (string? obj)
		{
			var nsobj = CFString.CreateNative (obj);
			invoker (BlockPointer, nsobj);
			CFString.ReleaseNative (nsobj);
		}
	}
}