[Bug] Crash XF for Mac 4.7.0.1080

[JohnHDev]

Description

Just updated from XF 4.5.0.657 to 4.7.0.1080.
App now crashes when attempting to render labels that contains formatted strings which are made up of several spans containing emoji's as well as text. The labels are also contained in grids.

The issue was introduced as early as 4.6, but Im not going to restore each version manually just to check.

Steps to Reproduce

Callstack:
at (wrapper managed-to-native) ObjCRuntime.Messaging.void_objc_msgSend_out_nfloat_out_nfloat_out_nfloat_out_nfloat(intptr,intptr,System.nfloat&,System.nfloat&,System.nfloat&,System.nfloat&)
at AppKit.NSColor.GetRgba (System.nfloat& red, System.nfloat& green, System.nfloat& blue, System.nfloat& alpha) [0x0000c] in /Library/Frameworks/Xamarin.Mac.framework/Versions/6.18.2.1/src/Xamarin.Mac/NSColor.g.cs:944
at Xamarin.Forms.Platform.MacOS.ColorExtensions.ToColor (AppKit.NSColor color) [0x00015] in <80383802214540fe948b297f6790b923>:0
at Xamarin.Forms.Platform.MacOS.FormattedStringExtensions.ToAttributed (Xamarin.Forms.Span span, Xamarin.Forms.BindableObject owner, Xamarin.Forms.Color defaultForegroundColor, Xamarin.Forms.TextAlignment textAlignment, System.Double lineHeight) [0x000c0] in <80383802214540fe948b297f6790b923>:0
at Xamarin.Forms.Platform.MacOS.FormattedStringExtensions.ToAttributed (Xamarin.Forms.FormattedString formattedString, Xamarin.Forms.BindableObject owner, Xamarin.Forms.Color defaultForegroundColor, Xamarin.Forms.TextAlignment textAlignment, System.Double lineHeight) [0x0001b] in <80383802214540fe948b297f6790b923>:0
at Xamarin.Forms.Platform.MacOS.LabelRenderer.UpdateFormattedText () [0x00033] in <80383802214540fe948b297f6790b923>:0
at Xamarin.Forms.Platform.MacOS.LabelRenderer.UpdateTextPlainText () [0x0004d] in <80383802214540fe948b297f6790b923>:0
at Xamarin.Forms.Platform.MacOS.LabelRenderer.UpdateText () [0x0001e] in <80383802214540fe948b297f6790b923>:0
at Xamarin.Forms.Platform.MacOS.LabelRenderer.OnElementChanged (Xamarin.Forms.Platform.MacOS.ElementChangedEventArgs`1[TElement] e) [0x0008c] in <80383802214540fe948b297f6790b923>:0

Expected Behavior

Not to crash.

Actual Behavior

Crash with the above call stack.

Basic Information

• Version with issue:
• Last known good version: XF 4.5.0.657
• IDE:
• Platform Target Frameworks:
  • iOS:
  • Android:
  • UWP:
• Android Support Library Version:
• Nuget Packages:
• Affected Devices:

Screenshots

Reproduction Link

Workaround

Setting the label TextColor appears to work as a hackaround/workaround.

[samhouts]

Can you please attach a small project that demonstrates this issue? Thanks!

[JohnHDev]

@samhouts I thought you might ask me for that. :)

If you haven't already, create a Mac app and add XF to it as per: https://devblogs.microsoft.com/xamarin/preview-bringing-macos-to-xamarin-forms/

Delete the main page and replace it with the following (and update the namespace accordingly):

`
using System;
using Xamarin.Forms;

namespace XF4iOSAndroidMacDemo
{
public class MainPage: ContentPage
{
// NSInvalidArgumentException: *** -getRed:green:blue:alpha: not valid for the NSColor Generic Gray Gamma 2.2 Profile colorspace 0 1; need to first convert colorspace.

    public MainPage()
    {
        Content = new StackLayout
        {
            Children =
            {
                new Label()
                {
                    HorizontalOptions = LayoutOptions.Center,
                    VerticalOptions = LayoutOptions.CenterAndExpand,
                    //TextColor = Color.Black,
                    FormattedText = new FormattedString
                    {
                        Spans =
                        {
                            new Span()
                            {
                                Text = "🔔🌀 Welcome to Xamarin.Forms!",
                            },
                        }
                    }
                }
            }
        };
    }
}

}
`

Ensure that the XF nuget is 4.7+ for the solution. I was using 4.7.0.1080.
Set the Mac project to be startup in the solution.
Run it. You should see an exception thrown: NSInvalidArgumentException: *** -getRed:green:blue:alpha: not valid for the NSColor Generic Gray Gamma 2.2 Profile colorspace 0 1; need to first convert colorspace.

Remove the TextColor commented out line.
Clean the solution (VS4Mac bug, need to clean before every build).
Run again, no crash.