Some properties not updating (eg VisualState setter not working for Button BackgroundColor) with AOT enabled

Description

The setter is not working properly when in release mode. In debug it works fine. Only noticed it for the backgroundcolor on button. TextColor works fine for button. Didn’t test anything other. Also only tested on android, don’t now if it’s the same for other platforms.

I created a simple project to demonstrate. It’s basicly the templete that you get when createing a new project with added checkbox to enable/disable the button:

<CheckBox x:Name="checkBox" />
            
<Button
    x:Name="CounterBtn"
    Text="Click me"
    HorizontalOptions="Center"
    IsEnabled="{Binding Source={x:Reference checkBox}, Path=IsChecked}"/>

Before	Debug	Release

Only the text color changed but the background didn’t in release mode.

Steps to Reproduce

1. Download linked project
2. Set to release mode
3. Run on local android device
4. Click the checkbox to enable/disable the button
5. See results

Link to public reproduction project repository

https://github.com/Kaiffa/maui-bug-visualstate-button-release

Version with bug

7.0 (current)

Last version that worked well

Unknown/Other

Affected platforms

Android

Affected platform versions

Android 12.0

Did you find any workaround?

Remapping the property from BackgroundColor to Background fixed the issue. This is easy to do in the maui program app builder:

.ConfigureMauiHandlers(_ => 
{
	LabelHandler.Mapper.AppendToMapping(
		nameof(View.BackgroundColor),
		(handler, View) => handler.UpdateValue(nameof(IView.Background)));
	ButtonHandler.Mapper.AppendToMapping(
		nameof(View.BackgroundColor),
		(handler, View) => handler.UpdateValue(nameof(IView.Background)));
})

Relevant log output

Visual studio 17.4.1

Android device used:
Samsung Galaxy A13, Android 12

[duindain]

Can this be backported when the PR is complete to .Net 7 please

We are also facing this in iOS for all buttons in our app in release mode where they use Visual state

[mattleibow]

After a vast amount of logging in places, I found that AOT affected the order of types being referenced - and thus our static fields were being initialized in “incorrect” orders.

This happened in our “Remap for Controls” section and in most cases we were replacing fields instead of adding properties. We had the correct order in Debug because we were maybe lucky, but the AOT compiler rather went by assembly at a time instead of JIT field init.

In any case, the contents of the mappers should not be affected by the order of the references. I can actually replicate the same issue if I add this code before anything in the MauiProgram:

ElementHandler.ElementMapper.GetKeys();
ViewHandler.ViewMapper.GetKeys();
ButtonHandler.Mapper.GetKeys();
Button.ControlsButtonMapper.GetKeys();
Element.ControlsElementMapper.GetKeys();
VisualElement.ControlsVisualElementMapper.GetKeys();

The issue is pretty simple now that I know what it is 😃

The mappers are set up in Core like this:

1. ElementHandler.ElementMapper adds the first level of properties
2. ViewHandler.ViewMapper takes a reference to the ElementHandler.ElementMapper field and wraps it
3. ButtonHandler.Mapper similarly wraps ViewHandler.ViewMapper
4. Button.ControlsButtonMapper then comes in and this is where things go wrong: it wraps the ButtonHandler.Mapper as it is designed
5. Element.ControlsElementMapper now comes in an wraps ElementHandler.ElementMapper and adds come more members
6. VisualElement.ControlsVisualElementMapper then wraps and appends to Element.ControlsElementMapper

This seems like it may work, but what is actually happening in 4-6 is that the field is replaced instead of being appended. This results in step 5 (Element.ControlsElementMapper) adding fields that never make it to the Button.ControlsButtonMapper because that init code has already run and copied the old mapper from 3.

Going to look at the best way to fix this to avoid order-based-init.