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[QUESTION] .Net 8 is supported? #2444

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KannanKrish opened this issue Apr 18, 2023 · 8 comments · Fixed by #2465
Closed

[QUESTION] .Net 8 is supported? #2444

KannanKrish opened this issue Apr 18, 2023 · 8 comments · Fixed by #2465

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@KannanKrish
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I am currently testing .net 8 maui project. That project have the SkiaSharp dependency. I can't run the project.

I am getting the following error

System.BadImageFormatException: 'Invalid field token 0x040000a1'

image

@leoslima13
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Same too me! But it's working fine on iOS

@dmenne
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dmenne commented May 11, 2023

And by reverting to .NET 7.0 I got a working version

@KannanKrish
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I hope .NET 8 preview 4 resolve this issue.

@deli-nik
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Same for me, I'm getting same error on Android. Works fine on Windows target though.

@jerry2007
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Same for me :-(

@jerry2007
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I hope .NET 8 preview 4 resolve this issue.

It didn't :-(

@dellis1972
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dellis1972 commented May 26, 2023

A workaround is to add the following to your app project.

<resources>
<declare-styleable name='SKCanvasView'>
	<attr name='ignorePixelScaling' format='boolean'/>
</declare-styleable>
</resources>

You can place this in a file Resources\values\attrs.xml. If its a Maui project then place this file in Platform\Android\Resources\values\attrs.xml

@mattleibow
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Thanks @dellis1972 for the workaround!

jonpryor pushed a commit to dotnet/android that referenced this issue Jun 9, 2023
Context: mono/SkiaSharp#2444
Context: mono/SkiaSharp#2465
Context: fcd7cf8
Context: dc3ccf2
Context: 3ec1b15

In Classic Xamarin.Android, `@(AndroidResource)` files were embedded
into assemblies as `@(EmbeddedResource)` entries.  While convenient,
this slowed down build times (as every assembly needed to be checked
to see if it had embedded resources), and this functionality was
removed for .NET 6 in fcd7cf8.  The replacement was to use `.aar`
files, typically located in the same directory as the assembly.

Unfortunately, it was easy to incorrectly migrate from the old system
to the new system, which was the case for the 
[SkiaSharp.Views (v2.88.3) NuGet Package][0], which *uses* an
[`@attr/ignorePixelScaling`][1] resource, but did not package it.

In .NET 6 and 7, this was "fine" *so long as* that resource value was
never used.  If it *was* used, then the results were undefined: a
"garbage" resource id value would be used, which would either be
invalid or refer to a *different* resource altogether!

.NET 8 introduces the Resource Designer Assembly (dc3ccf2), which
involves *rewriting non-.NET 8 assemblies* to use the Resource
Designer Assembly, which in turn requires that all resources exist.

Which brings us to mono/SkiaSharp#2444: because the `SkiaSharp.Views`
NuGet package references but did not redistribute the
`@attr/ignorePixelScaling` resource, the assembly rewriter would
*skip over* the missing resource name, resulting in an invalid
assembly.  This in turn would result in a *runtime crash*:

	System.BadImageFormatException: 'Invalid field token 0x040000a1'

We decided that instead of ignoring missing resource fields, we
should error out.

Update `FixLegacyResourceDesignerStep` to report an error if we
cannot find the required Resource Designer Assembly property which
matches a "legacy" field.

In Debug builds, this will result in an XA8000 error:

	error XA8000: Could not find Android Resource '@attr/ignorePixelScaling'.
	Please update @(AndroidResource) to add the missing resource.

For Release builds, this instead results in an IL8000 error:

	error IL8000: Could not find Android Resource '@attr/ignorePixelScaling'.
	Please update @(AndroidResource) to add the missing resource.

Note that this only moves a runtime error to a compile-time error.
The fix for mono/SkiaSharp#2444 is mono/SkiaSharp#2465, which adds
`SkiaSharp.Views.Android.aar` to the `SkiaSharp.Views` NuGet package.
This should be fixed in the (forthcoming) SkaSharp.Views 2.88.4.
[A *workaround* for mono/SkiaSharp#2444][3] is to define the
`@attr/ignorePixelScaling` resource within your app project.

Additionally, we found another problem while investigating
mono/SkiaSharp#2444 around resource name case sensitivity.  Not all
Android Resource names need to be lowercase; generally only those
that are based on *filenames* need to be lowercase, e.g.
`@layout/main`.  Resources which are defined within XML containers,
such as [string resources][2], may contain uppercase letters.

While looking at the output for the test app, it turns out the final
assembly does NOT include the expected `anim` based resources.
Looking at the IL we found that the properties were NOT being fixed
up to use the correct casing, e.g. we have `enterfromright` instead
of `EnterFromRight`.  Further investigation tracked the issue down to
the `RTxtParser`; This class uses the `case_map.txt` file for lookup.
The `case_map.txt` file contains entries such as:

	animation/enterfromleft;animation/EnterFromLeft
	animation/enterfromright;animation/EnterFromRight

these allow us to map the "android" lower cased items to the C# cased
items.   The problem was we were not mapping `anim` to `animation`.
There is a method called `ResourceParser.GetNestedTypeName()` which
is used to map the android resource type to the managed resource type.
For example it maps `anim` to `Animation` and `bool` to `Boolean`.
This was not being called when we tried to map the resource.  As a
result we never found the correct cased entry.  This would result in
the final Resource Designer Assembly containing the lower cased
"android" naming of the property and not the correctly cased one
which the C#/IL would be using; the fields were never fixed up. 

The fix is to make sure we call `ResourceParser.GetNestedTypeName()`
when calculating the final property name in the `RTxtParser`.

[0]: https://www.nuget.org/packages/SkiaSharp/2.88.3
[1]: https://github.com/mono/SkiaSharp/blob/99c2437b1055dc6eb8ee25e90e5ad4afa695aa89/source/SkiaSharp.Views/SkiaSharp.Views.Android/Resources/values/attrs.xml#L4
[2]: https://developer.android.com/guide/topics/resources/string-resource
[3]: mono/SkiaSharp#2444 (comment)
@ghost ghost locked as resolved and limited conversation to collaborators Jul 8, 2023
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7 participants