[UWP][IL2CPP] Export fails when trying to preserve class in .winmd via link.xml

Hi, here's the long story:
Using Unity 2018.2.13f building UWP IL2CPP and using Vungle SDK 6.2.0 with our own wrapper (not the unity plugin).
So, we are putting VungleSDK.winmd in Assets/Plugins/WSA
Note that Strip Engine Code is Enabled.

The export goes fine. Then building in VS and deploying to a device is also fine.
During runtime, when trying to initialize the VungleSDK the diagnostic callback of the sdk throws the following error:

Unobserved Task Exception was a Publisher Exception, type: VungleSDK.VungleAd, ex: System.Runtime.Serialization.InvalidDataContractException: No set method for property 'UseGzip' in type 'VungleSDK.NetworkRequest'.

I'm guessing the striping process stripped the UseGzip method of VungleSDK.NetworkRequest (which is a protected class of the VungleSDK)

So... we tried adding the following in link.xml

<linker>
<assembly fullname="VungleSDK">
<type fullname="VungleSDK.NetworkRequest" preserve="all"/>
</assembly>
</linker>

Unfortunately, after doing this the export process started crashing with the following exception:

Failed running C:\dev\tools\unity\Editor\Data\il2cpp/build/UnityLinker.exe -out="C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\tempStrip" -x="C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Core.xml" -x "C:\Users\Baceto\AppData\Local\Temp\tmpa654603.tmp" -x "C:\Users\Baceto\AppData\Local\Temp\tmp1ea6a612.tmp" -x "C:\Users\Baceto\AppData\Local\Temp\tmp385298bb.tmp" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Accessibility.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\AI.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Animation.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\AR.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\AssetBundle.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Audio.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Cloth.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Core.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\CrashReporting.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Director.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\GameCenter.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Grid.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\ImageConversion.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\IMGUI.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Input.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\JSONSerialize.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Localization.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\ParticlesLegacy.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\ParticleSystem.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\PerformanceReporting.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Physics.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Physics2D.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\ScreenCapture.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\SharedInternals.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\SpriteMask.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\SpriteShape.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Streaming.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\StyleSheets.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Substance.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Terrain.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\TerrainPhysics.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\TextRendering.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Tilemap.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\UI.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\UIElements.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\UNET.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\UnityAnalytics.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\UnityConnect.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\UnityWebRequest.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\UnityWebRequestAssetBundle.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\UnityWebRequestAudio.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\UnityWebRequestTexture.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\UnityWebRequestWWW.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Vehicles.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Video.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\VR.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\Wind.xml" -x "C:\dev\tools\unity\Editor\Data\PlaybackEngines\MetroSupport\Whitelists\XR.xml" -x "C:\dev\projects\train\unity\Assets\link.xml" -d "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\Assembly-CSharp-firstpass.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\Assembly-CSharp.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\Unity.TextMeshPro.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\UnityEngine.UI.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\DOTween.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\NativeComm.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\NestedPrefabs.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\UnityEngine.Analytics.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\I18N.CJK.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\I18N.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\I18N.MidEast.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\I18N.Other.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\I18N.Rare.dll" -a "C:\dev\projects\train\unity\Temp\StagingArea\Data\Managed\I18N.West.dll" --dotnetruntime=il2cpp --dotnetprofile=unityaot --use-editor-options

stdout:
Fatal error in Unity CIL Linker
Mono.Linker.LoadException: Error while processing references of 'Assembly-CSharp, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' ---> Mono.Linker.LoadException: Error while processing references of 'GCore, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' ---> Mono.Linker.LoadException: Error while processing references of 'NativeComm, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' ---> System.NullReferenceException: Object reference not set to an instance of an object.
at Unity.IL2CPP.Common.WindowsRuntimeAwareMetadataResolver.FindTypeInUnknownWinmd(TypeReference type)
at Mono.Cecil.TypeReference.Resolve()
at Unity.IL2CPP.Common.AssemblyDependenciesComponent.ResolveWindowsRuntimeReferences(AssemblyDefinition assembly)
at Unity.IL2CPP.Common.AssemblyDependenciesComponent.CollectAssemblyDependencies(AssemblyDefinition assembly)
at Unity.IL2CPP.Common.AssemblyDependenciesComponent.GetReferencedAssembliesFor(AssemblyDefinition assembly)
at Unity.Linker.UnityLinkContext.ResolveReferences(AssemblyDefinition assembly)
at Mono.Linker.Steps.LoadReferencesStep.ProcessReferences(AssemblyDefinition assembly)
at Mono.Linker.Steps.LoadReferencesStep.ProcessReferences(AssemblyDefinition assembly)
--- End of inner exception stack trace ---
at Mono.Linker.Steps.LoadReferencesStep.ProcessReferences(AssemblyDefinition assembly)
at Mono.Linker.Steps.LoadReferencesStep.ProcessReferences(AssemblyDefinition assembly)
--- End of inner exception stack trace ---
at Mono.Linker.Steps.LoadReferencesStep.ProcessReferences(AssemblyDefinition assembly)
at Mono.Linker.Steps.LoadReferencesStep.ProcessReferences(AssemblyDefinition assembly)
--- End of inner exception stack trace ---
at Mono.Linker.Steps.LoadReferencesStep.ProcessReferences(AssemblyDefinition assembly)
at Mono.Linker.Steps.BaseStep.Process(LinkContext context)
at Mono.Linker.Pipeline.Process(LinkContext context)
at Unity.Linker.UnityDriver.Run()
at Unity.Linker.UnityDriver.RunDriverWithoutErrorHandling()
at Unity.Linker.UnityDriver.RunDriver()
stderr:

UnityEngine.Debug:LogError(Object)
UnityEditorInternal.Runner:RunProgram(Program, String, String, String, CompilerOutputParserBase) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/BuildUtils.cs:128)
UnityEditorInternal.Runner:RunManagedProgram(String, String, String, CompilerOutputParserBase, Action`1) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/BuildUtils.cs:73)
UnityEditorInternal.AssemblyStripper:RunAssemblyLinker(IEnumerable`1, String&, String&, String, String) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/AssemblyStripper.cs:91)
UnityEditorInternal.AssemblyStripper:StripAssembliesTo(String[], String[], String, String, String&, String&, String, IIl2CppPlatformProvider, IEnumerable`1, BuildTargetGroup) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/AssemblyStripper.cs:84)
UnityEditorInternal.AssemblyStripper:RunAssemblyStripper(IEnumerable, String, String[], String[], String, IIl2CppPlatformProvider, RuntimeClassRegistry) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/AssemblyStripper.cs:215)
UnityEditorInternal.AssemblyStripper:StripAssemblies(String, IIl2CppPlatformProvider, RuntimeClassRegistry) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/AssemblyStripper.cs:115)
UnityEditorInternal.IL2CPPBuilder:Run() (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:170)
UnityEditorInternal.IL2CPPUtils:RunIl2Cpp(String, String, IIl2CppPlatformProvider, Action`1, RuntimeClassRegistry) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:35)
PostProcessUAPIl2Cpp:RunIL2CPP() (at C:/buildslave/unity/build/PlatformDependent/MetroPlayer/Extensions/Managed/PostProcessUAPIl2Cpp.cs:464)
PostProcessWinRTrocess() (at C:/buildslave/unity/build/PlatformDependent/MetroPlayer/Extensions/Managed/PostProcessWinRT.cs:228)
UnityEditor.DefaultBuildMethods:BuildPlayer(BuildPlayerOptions)
UnityEditorHelper.BundleManager:<startup>b__5_0(BuildPlayerOptions)
UnityEngine.GUIUtilityrocessEvent(Int32, IntPtr)

 

Seems like the missing 'UseGzip' method is not stripped. It looks like Vungle has a problem with the config deserialization. The data contains reference to a missing property.

Anyway, I think the NullReferenceException in the Unity CIL Linker shouldn't happen under any circumstance

 

Thanks for the linker info. Submitted report for the null reference.
Case 1094644