Csc errors in Resource.designer.cs during a regular build

[jonathanpeppers]

Steps to Reproduce

Filing this, as I have not figured out what is wrong yet...

1. Clone Xamarin.Forms or run git clean -dxf
2. Run Xamarin.Forms.ControlGallery.Android -- a Xamarin.Android app project
3. You might get compiler errors in activities using fields from Resource.designer.cs

Errors
    AppCompat\NavigationPageRenderer.cs(461,34): error CS0117: 'Resource.Attribute' does not contain a definition for 'actionBarSize' 
    Renderers\ShellItemRenderer.cs(60,45): error CS0117: 'Resource' does not contain a definition for 'Layout'
... plus more

Rebuilding Xamarin.Forms.ControlGallery.Android fixes the issue.

The actual file looked like this:

#pragma warning disable 1591
//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//     Runtime Version:4.0.30319.42000
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

[assembly: global::Android.Runtime.ResourceDesignerAttribute("Xamarin.Forms.Platform.Android.Resource", IsApplication=false)]

namespace Xamarin.Forms.Platform.Android
{
	
	
	[System.CodeDom.Compiler.GeneratedCodeAttribute("Xamarin.Android.Build.Tasks", "1.0.0.0")]
	public partial class Resource
	{
		
		static Resource()
		{
			global::Android.Runtime.ResourceIdManager.UpdateIdValues();
		}
		
		public partial class Attribute
		{
			
			static Attribute()
			{
				global::Android.Runtime.ResourceIdManager.UpdateIdValues();
			}
			
			private Attribute()
			{
			}
		}
	}
}
#pragma warning restore 1591

In a working example, I see a lot of logs like this:

  - Not remapping resource: Animation.abc_fade_in
  - Not remapping resource: Animation.abc_fade_out
... plus many more

Those are absent in the failing build log.

Expected Behavior

A regular build should not encounter build errors.

Actual Behavior

You get build errors in code using Resource.designer.cs.

Version Information

@PureWeen was hitting this in VS Windows, using Xamarin.Android 9.4.0.34.

I wasn't able to reproduce myself, but logs are attached.

Log File

An example of a working/non-working build in here: aapt2.zip

[jonathanpeppers]

I found out how to reproduce this command-line:

> git clean -dxf
> msbuild Xamarin.Forms.sln /restore /m

You can solve the issue by either removing /m (builds projects in parallel), or adding /p:AndroidUseAapt2=False.

Here is a log: error.zip

[brendanzagaeski]

Release status update

A new Release version has now been published that includes the fix for this item.

Fix included in Xamarin.Android 10.0.0.43

Fix included on Windows in Visual Studio 2019 version 16.3. To get the new version that includes the fix, check for the latest updates or install the latest version from https://visualstudio.microsoft.com/downloads/.

Fix included on macOS in Visual Studio 2019 for Mac version 8.3. To get the new version that includes the fix, check for the latest updates on the Stable updater channel.