Resource.designer.fs is not being generated on build

[nbevans]

Steps to Reproduce

1. Create a Android app in VS using the F# template
2. Try to build it.
3. Observe that the Resource.designer.fs file is not generated. No resources can be resolved at runtime by doing say:

        let foo = Application.Context.Resources.GetString(Resource_String.my_string_value)

Indeed on a fresh app as per Step 1 then Resource_String won't even exist in the codebase, so immediate compile error. If it did exist (as in our case, a copy from 2020) then the auto-generated ID numbers will be out of date and will result in runtime exceptions when trying to resolve those resource IDs.

Expected Behavior

The Resource.designer.fs file should be generated on each build.

Actual Behavior

The Resource.designer.fs file is not being generated, ever.

Version Information

Microsoft Visual Studio Community 2019
Version 16.11.5

Notes

I am some what shocked to be creating this issue. It appears that F# builds have been broken now for sometime. I have only just noticed it because it is quite rare we need to make changes to our Resources in our app. There has been an issue open in the Xamarin.Android.FSharp.ResourceProvider project for a long time but there is no resolution. As this is a blocking issue and affects production apps I have created a issue here for better visibility.

[nbevans]

xamarin/Xamarin.Android.FSharp.ResourceProvider#9

[jonathanpeppers]

This happened for me in VS 2022:

But then I Rebuild and it starts working:

I suspect this problem has always been here? It seems like the first design-time build isn't working, but future ones work.

[nbevans]

Hmm.

What happened to the Resource_String, Resource_Id, Resource_<resource type> approach?

When did it start relying on a type provider like this?

This has caught me out because I don't actually know when the regression occurred. All I know is, my Resource.designer.fs is last modified mid-2020 (!) and no matter what I try now (rebuilds the lot) it won't update it. It seems to no longer be in use (except my Resource_* references to it all over my codebase).

[jonathanpeppers]

I just tested the default Xamarin.Android F# template.

You might create one of those and compare with your project.

[nosami]

I suspect this problem has always been here? It seems like the first design-time build isn't working, but future ones work.

No the IDE didn't used to show squiggles after the initial design time build had completed. Doesn't seem like a blocking issue though.

What happened to the Resource_String, Resource_Id, Resource_ approach?

It never really worked properly for many people as the F# codegen often produced uncompilable code. Also Xamarin.Android relies on public static fields being assigned at runtime. F# does not support public static fields so a new approach was required.

When did it start relying on a type provider like this?

Around 5 years ago.

[nbevans]

I suspect this problem has always been here? It seems like the first design-time build isn't working, but future ones work.

No the IDE didn't used to show squiggles after the initial design time build had completed. Doesn't seem like a blocking issue though.

What happened to the Resource_String, Resource_Id, Resource_ approach?

It never really worked properly for many people as the F# codegen often produced uncompilable code. Also Xamarin.Android relies on public static fields being assigned at runtime. F# does not support public static fields so a new approach was required.

When did it start relying on a type provider like this?

Around 5 years ago.

What was updating our Resource.designer.fs through all these commits until 2020?

We're always broadly up to date with Visual Studio releases, never more than 1 to 2 releases behind for more than a month or so. It is not like we haven't updated VS for the past year.

[nosami]

Resouce.designer.fs may have still been generated, but it was deprecated around 5 years ago.

Xamarin.Android must have finally stopped producing this file.

[jonathanpeppers]

Resource.designer.fs was removed from Xamarin.Android in ~January 2020:

86be621

Documented in release notes here:

https://docs.microsoft.com/en-us/xamarin/android/release-notes/10/10.3#removal-of-f-resourcedesignerfs-file-support

From what I remember, it was done so we could remove .NET framework-only types and support dotnet build in .NET 6.

[jonathanpeppers]

I think we understand the cause here. If you have further issues migrating to Xamarin.Android.FSharp.ResourceProvider, file a new issue and we can take a look, thanks.