Trimming/Linker breaks SpriteFont loading

Android
#1

This can be easily reproduced by creating a new Android project (MonoGame 3.8.1.303, .NET6, Android 31), though I have the same issue with iOS. Add a new SpriteFont to your content (default Arial template is fine), and then try to build a release build (or enable the trimmer/linker on a debug build to actually see the error).

It will crash when attempting to load the SpriteFont with Could not find ContentTypeReader Type

I have tried to set the trim mode to SDK Only. I have tried to add a RootAssembly directive for MonoGame.Framework. I’ve also attempted it for Microsoft.Xna.Framework.Content.ContentTypeReader as I had read in another thread, but that errors out saying it cannot be found.

The only way I’ve been able to build my mobile builds is by disabling the trimmer/linker entirely.

Can't load font in release mode on Android
Crash for release build on iOS
#2

I believe I’ve found a solution for this. After ripping into the SpriteFont’s XNB, I discovered that the MG content loader uses System.Char by reflection when loading SpriteFonts. So, stop the linker from removing it. I tried a couple methods to only block the trimming of the System.Char type without luck. I would be interested if anyone else is doing this a bit cleaner. Here’s what you can do:

Create an XML file (ex: TrimmerRoots.xml) with this content:

<linker>
	<assembly fullname="System.Private.CoreLib" preserve="all" />
	<assembly fullname="mscorlib" preserve="all" />
</linker>

Then reference that in your .csproj with:

<ItemGroup>
	<TrimmerRootDescriptor Include="TrimmerRoots.xml" />
</ItemGroup>
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Android Release build can't find ContentTypeReader
#3

You, my friend, are a wizard! thank you

1 Like