Xamarin-android: System.Runtime.CompilerServices.Unsafe linked away in release leading to crashes

[ddobrev]

This is most probably related to https://github.com/aspnet/EntityFrameworkCore/issues/8922 . None of the workarounds there help. The major problem is that it's simply impossible to force the linker to preserve an entire assembly.

Steps to Reproduce

1. Use a library, such as Microsoft.Extensions.Identity.Stores, which (indirectly) depends on System.Runtime.CompilerServices.Unsafe, in a Xamarin.Android project;
2. Build the project in Release - ensure linking is not set to "None";
3. Run it on a device.

Expected Behavior

The application runs.

Actual Behavior

The application does not load at all with:
Could not load assembly 'System.Runtime.CompilerServices.Unsafe' during startup registration.

Version Information

Microsoft Visual Studio Community 2017
Version 15.5.3
VisualStudio.15.Release/15.5.3+27130.2020
Microsoft .NET Framework
Version 4.7.02558

Installed Version: Community

Visual Basic 2017 00369-60000-00001-AA416
Microsoft Visual Basic 2017

Visual C# 2017 00369-60000-00001-AA416
Microsoft Visual C# 2017

Visual C++ 2017 00369-60000-00001-AA416
Microsoft Visual C++ 2017

Visual F# 4.1 00369-60000-00001-AA416
Microsoft Visual F# 4.1

Application Insights Tools for Visual Studio Package 8.10.01106.1
Application Insights Tools for Visual Studio

ASP.NET and Web Tools 2017 15.0.31127.0
ASP.NET and Web Tools 2017

ASP.NET Core Razor Language Services 1.0
Provides languages services for ASP.NET Core Razor.

ASP.NET Web Frameworks and Tools 2017 5.2.51007.0
For additional information, visit https://www.asp.net/

Azure App Service Tools v3.0.0 15.0.31106.0
Azure App Service Tools v3.0.0

Common Azure Tools 1.10
Provides common services for use by Azure Mobile Services and Microsoft Azure Tools.

EZ-GIT 1.7.2

GradleBindings.VisualStudio 1.0
Creates Xamarin Android Binding projects from a gradle file.

JavaScript Language Service 2.0
JavaScript Language Service

Merq 1.1.17-rc (cba4571)
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Microsoft Azure Tools 2.9
Microsoft Azure Tools for Microsoft Visual Studio 2017 - v2.9.51120.3

Microsoft Continuous Delivery Tools for Visual Studio 0.3
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Microsoft JVM Debugger 1.0
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Microsoft Visual Studio Tools for Containers 1.1
Develop, run, validate your ASP.NET Core applications in the target environment. F5 your application directly into a container with debugging, or CTRL + F5 to edit & refresh your app without having to rebuild the container.

Microsoft Visual Studio VC Package 1.0
Microsoft Visual Studio VC Package

Mono Debugging for Visual Studio 4.8.4-pre (3fe64e3)
Support for debugging Mono processes with Visual Studio.

NpgsqlVSPackage Extension 1.0
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NuGet Package Manager 4.5.0
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Qt Visual Studio Tools 2.1.2
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SQL Server Data Tools 15.1.61710.120
Microsoft SQL Server Data Tools

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Visual Studio Tools for CMake 1.0
Visual Studio Tools for CMake

VisualStudio.Mac 1.0
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Xamarin 4.8.0.757 (7f9ec2a)
Visual Studio extension to enable development for Xamarin.iOS and Xamarin.Android.

Xamarin Designer 4.8.188 (c5813fa34)
Visual Studio extension to enable Xamarin Designer tools in Visual Studio.

Xamarin.Android SDK 8.1.3.0 (HEAD/ef47226b7)
Xamarin.Android Reference Assemblies and MSBuild support.

Xamarin.iOS and Xamarin.Mac SDK 11.6.1.2 (6857dfc)
Xamarin.iOS and Xamarin.Mac Reference Assemblies and MSBuild support.

[jonpryor]

it's simply impossible to force the linker to preserve an entire assembly

It should be possible to preserve an entire assembly, either via the $(AndroidLinkSkip) MSBuild property or via the @(LinkDescription) Build action and a linker configuration file.

[ddobrev]

Either does not work. I think the problem might have to do with System.Runtime.CompilerServices.Unsafe being considered a "reference-only" assembly.

[radekdoulik]

Not sure what "reference-only" assembly mean here. Could you please attach a project which reproduces the issue?

Are you sure the AndroidLinkSkip is indeed set? Do you have diagnostic build output?

[jonpryor]

@radekdoulik: "Reference only assembly" means Issue #1154. It is an assembly with the System.Runtime.CompilerServices.ReferenceAssemblyAttribute assembly-level custom attribute.

Mono will not load reference assemblies.

[ddobrev]

UnsafeLinkerBug.zip

[ddobrev]

In case it doesn't work, try a Xamarin.Forms application in which the .NET Standard has the reference to Stores.

[radekdoulik]

Wasn't able to reproduce it with XA 8.1.1.1. I will try 8.1.5 next.

BTW, I don't see AndroidLinkSkip property set in the project file.

[ddobrev]

@radekdoulik try "AndroidLinkSkip" yourself, I have little intention of reapplying once more all the workarounds which failed to work. Also, see the issue I have linked at the beginning.

[radekdoulik]

Works OK for me in XA 8.1.5 as well.

[ddobrev]

Try Xamarin.Forms.

[radekdoulik]

OK, I have got a link to a simple app from @JonDouglas which reproduces the issue - https://github.com/aspnet/EntityFrameworkCore/files/1372571/Desktop.zip (App2). Looks like it is indeed related to https://github.com/xamarin/xamarin-android/issues/1154

[JonDouglas]

A simple reproduction is the following:

1. Create a File->New Xamarin.Android Project
2. Include Microsoft.EntityFrameworkCore.Sqlite as a <PackageReference> from NuGet.

Here are some relevant logs similar to those in #1154

2>BuildApk Task
2>  ApkInputPath: obj\Debug\android\bin\packaged_resources
    ...
2>    obj\Debug\android\assets\System.Runtime.CompilerServices.Unsafe.dll

2>BuildApk Task
    ...
2>Task Parameter:
2>    EmbeddedNativeLibraryAssemblies=
   ...
2>                Version=
2>        C:\Users\dougl\.nuget\packages\system.runtime.compilerservices.unsafe\4.4.0\ref
2>etstandard2.0\System.Runtime.CompilerServices.Unsafe.dll
2>                CopyLocal=false
2>                FusionName=System.Runtime.CompilerServices.Unsafe, Version=4.0.3.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
2>                ImageRuntime=v4.0.30319
2>                NuGetIsFrameworkReference=false
2>                NuGetPackageId=System.Runtime.CompilerServices.Unsafe
2>                NuGetPackageVersion=4.4.0
2>                NuGetSourceType=Package
2>                OriginalItemSpec=C:\Users\dougl\.nuget\packages\system.runtime.compilerservices.unsafe\4.4.0\ref
2>etstandard2.0\System.Runtime.CompilerServices.Unsafe.dll
2>                Private=false
2>                ReferenceAssembly=C:\Users\dougl\.nuget\packages\system.runtime.compilerservices.unsafe\4.4.0\ref
2>etstandard2.0\System.Runtime.CompilerServices.Unsafe.dll
2>                ReferenceSourceTarget=ResolveAssemblyReference
2>                ResolvedFrom={RawFileName}

1>Task "LinkAssemblies" (TaskId:327)
1>  Task Parameter:UseSharedRuntime=True (TaskId:327)
1>  Task Parameter:MainAssembly=obj\Debug\android\assets\EntityFrameworkFailure.dll (TaskId:327)
1>  Task Parameter:OutputDirectory=obj\Debug\linkdst\ (TaskId:327)
1>  Task Parameter:OptionalDestinationDirectory=obj\Debug\android\assets\ (TaskId:327)
1>  Task Parameter:LinkMode=None (TaskId:327)
1>  Task Parameter:LinkOnlyNewerThan=obj\Debug\link.flag (TaskId:327)
1>  Task Parameter:
1>      ResolvedAssemblies=
    ...
1>          C:\Users\dougl\.nuget\packages\system.runtime.compilerservices.unsafe\4.4.0\ref\netstandard2.0\System.Runtime.CompilerServices.Unsafe.dll

[ddobrev]

@radekdoulik until the fix is released, is there a reliable workaround?

[dazinator]

I have just hit this after converting my csproj from using packages.config to using packagereference. Prior to that my app was working but I had to use linker mode "SdkOnly". Now after converting to package reference, system.runtime.compilerservices.unsafe gets linked away.

[radekdoulik]

@ddobrev I don't know about any workaround at this point. At least not from linker perspective as the assembly is not removed by the linker. It is present in the apk, but it is not loaded because it has System.Runtime.CompilerServices.ReferenceAssemblyAttribute.

As can be seen from logcat output:

D/Mono    (27963): Image addref System.Runtime.CompilerServices.Unsafe[0xadddc760] -> System.Runtime.CompilerServices.Unsafe.dll[0xb01af600]: 2
D/Mono    (27963): Image for assembly 'System.Runtime.CompilerServices.Unsafe' (System.Runtime.CompilerServices.Unsafe.dll) has ReferenceAssemblyAttribute, skipping

In case you are using <PackageReference> in your csproj file, you might try to use package.config file instead as a temporary solution?

[ddobrev]

@radekdoulik I see. Could you please at least verify in your reproduction that using package.config instead does work?

[radekdoulik]

@ddobrev OK, tried it with the App2 repro case and it works. It looks like it might work for you too.

[ddobrev]

@radekdoulik thank you. If you could just upload the project here as a future reference, I think it would be of immense help to everyone.

[radekdoulik]

App2.zip

This is an updated app from https://github.com/xamarin/xamarin-android/issues/1196#issuecomment-358028103. It uses packages.config file for nuget packages instead of <PackageReference> element in the App2.csproj file.

The updated app runs OK, so using packages.config might be temporary workaround before the #1154 is fixed.

[JORGEGO]

Any new workaround... after migrate from legay Xamarin.forms to .NET standard 2.0 same issue when start debug it stop...
Today has delivery 15.5.4 visual studio 2017 and persist the same error...

[JonDouglas]

@JORGEGO 15.5.4 had no fixes for Xamarin.Android. We do not have a direct fix for this issue yet as the only known workaround is to use packages.config instead of <PackageReference> when referencing from NuGet. You can change this setting in your NuGet options in Visual Studio. We are still investigating and will be providing any other known workarounds prior to a release.

[JORGEGO]

Let me ask it is possible use package.config for .NET standard 2.0 projects?

[ddobrev]

@JORGEGO yes but it requires a little manual work. You need to remove all package references, ensure there are no "RestoreProjectStyle" properties in your csproj and readd your packages.

[ddobrev]

@radekdoulik this one finally works. Thank you very much.

[smitter86]

I've resolved it by following:

1. Re-add nuget packages in Mobile.Android project with using packages.config;
2. Add nuget package System.Runtime.CompilerServices.Unsafe to Android project (it should be located in ../packages folder in your root solution folder);
3. Removed lib System.Runtime.CompilerServices.Unsafe from C:\Users\%User%.nuget\packages\netstandard.library\2.0.0;
4. Add reference to this lib manualy, using project references.

[ddobrev]

@smitter86 I don't know, just 1. works for me.

[smitter86]

@ddobrev My solution was for those who run into issue like "A reference to %assembly% could not be added. This component is already automatically referenced by the build system."

[angelcalvasp]

Any updates on this?

[radekdoulik]

1154 needs to be fixed first.

[danielmeza]

There is a similar error on iOS with the same assembly in the OT process.
We hope a hotfix on this.

[DatBluBat]

The only solution that worked for me:
https://github.com/xamarin/xamarin-android/issues/1162#issuecomment-359475008

1. I've just copied the content from the link above and saved as UnsafeFix.xml file in the Android project folder.
2. Then just added:
   <Import Project="UnsafeFix.xml" />
   at the end of android .csproj file, just before </Project>
3. Cleared everything, recompiled and it finally worked!

No need to change anything else.

[aritchie]

There is an issue on the iOS side which is similar around System.Runtime.CompilerServices.Unsafe - https://github.com/xamarin/xamarin-macios/issues/3199

[DatBluBat]

@aritchie
I didn't notice that unitl I've switched to Release configuration and an error poped out during iOS compilation:
Error MT3001: Could not AOT the assembly

What I did to make compilation work (on mac) is after restoring nuget packages go to ~/.nuget/system.runtime.compilerservices.unsafe/4.4.0
and delete "ref" folder then make a copy of "lib" folder and rename the copy back to "ref". This should work also for android instead of the fix I've referenced above.

[aritchie]

@DatBluBat thanks - I gave that a try which got me past the AOT issue, but smack into another one referenced in the other thread

[johnwmcintosh]

I'm having this problem with EF Core 2.0.1 as described here https://stackoverflow.com/questions/48956433/ef-core-2-0-1-unsafe-in-xamarin-android

@JonDouglas asked I post a "reaction" here. Not sure what that means so I'm just using a comment.

[softlion]

Silently waiting for a resolution of this since december.

[wyldebill]

I tried a file new project with Xamarin Forms and EF 2.0.1 in VS2017 v15.6.1 to see where migrations is at with SQLite. This combination is a no-go right now with the assembly not being loaded at runtime.

[brian8227]

Having the same problem as well. Any news of a fix?

[radekdoulik]

It should be fixed soon by https://github.com/xamarin/xamarin-android/pull/1356

[filoe]

Already fixed now?

[EhRom]

I have the same problem with VS 2017 15.6.4. @smitter86, how to "re-add nuget packages in Mobile.Android project with using packages.config" ? I did not found enough clear instructions to do this. I'd like to make this only for the Android project.

[dyardyGIT]

Solution?

[EhRom]

Yes. First you have to delete all the packages in your project. Then re-add the first pacakge. A prompt should appear: choose the package.config method. Re-add the other packages. It should work.

[dyardyGIT]

This is a netstandard 2 project (xamarin.forms). I have tried a number of ways to get it to revert to packages.config approach. Including this approach as shown on SO https://stackoverflow.com/questions/45962998/switch-back-to-packages-config

So, at this moment wanting to use ef.core sqllite with xamarin forms .netstandard2 project and struggling to get it back to packages.config approach.

[tipa]

@EhRom that is a workaround, not a solution

[dyardyGIT]

Gosh, I have tried a number of the variations above, modifying nupkg, removing lib's, refs, dlls, reinstalled etc. Still no solution to this error

04-07 15:46:50.825 D/Mono (29229): Assembly Loader probing location: 'System.Runtime.CompilerServices.Unsafe'.
04-07 15:46:50.825 F/monodroid-assembly(29229): Could not load assembly 'System.Runtime.CompilerServices.Unsafe' during startup registration.
04-07 15:46:50.825 F/monodroid-assembly(29229): This might be due to an invalid debug installation.
04-07 15:46:50.825 F/monodroid-assembly(29229): A common cause is to 'adb install' the app directly instead of doing from the IDE.

[denmarksdev]

I follow these steps of hongliyu2002 https://forums.realm.io/t/could-not-load-assembly-system-runtime-compilerservices-unsafe-during-startup-registration/974/4

1. Go to C:\Users\%user%.nuget\system.runtime.compilerservices.unsafe\4.4.0, and delete "ref" folder then make a copy of "lib" folder and rename the copy back to "ref".
2. Cleanup all the "bin" and "obj" folders in the projects.
3. Rebuild and run..

This simple workaround , works for me :)
My current version is Xamarin.Forms 2.5.1.444934

[AhmedShamel]

@denmarksdev
Thanks man, your solution worked for me.

[ghost]

Can please give anybody a hint if that does help although with the problem that the Command does not fire?

https://github.com/xamarin/Xamarin.Forms/issues/1599

We have no crash or exception anywhere...

[jonpryor]

I suspect that this issue is in part duplicative of #1154 and #1162 (plus many followup commits), which revolve around handling of reference assemblies. It would be interesting to re-try this against e.g. Visual Studio 15.7 Preview 4.

[dgerding]

I'm getting the problem on release version of VS and .net Core. Trying different workarounds. Anyone know if it's still a problem in 15.7 Preview 4? (Maybe that will ship this week at Build?)

[SalimiHabib]

it is also appear after Realm installation
may be related to ABI settings , for Debug builds on armeabi (it notified in Realm documentation)
but i still have this problem unsolved .

[dominik-weber]

@jonpryor I have just tested this with VS 15.7.0, seems to be fixed! 😊

[cheles]

I can confirm that latest vs 15.7 with XF 3.0.0.446417 fixed this issue.

[JonDouglas]

Based on two confirmations and also confirming it myself on a local machine using 15.7, I am going to close this issue based on https://github.com/xamarin/xamarin-android/issues/1154 https://github.com/xamarin/xamarin-android/pull/1356 and https://github.com/xamarin/xamarin-android/issues/1162 being available in 15.7 builds.

Please feel free to comment on this issue if you are still running into this issue.

[wjvii]

We are running Xamarin Forms 3.0 and 3.1 and Visual Studio 2017 15.7.1 and when we try to run the apk we create in VS or App Center we still get "Could not load assembly 'System.IO.Packaging' during startup registration."

[alexdrl]

I am getting this error with a fresh copy of https://github.com/cwrea/XamarinTodo
Using VS 15.7.3.

[cwrea]

@alexdrl Odd -- I am not encountering the issue. I am able to compile and run the Android app in the latest version of the sample (https://github.com/cwrea/XamarinTodo/tree/NETStd20_EFCore203 and corresponding to master at the moment), and I'm also using Visual Studio 15.7.3, with Xamarin.Android SDK 8.3.3.2 (HEAD/dffc59120).

When I created that version, I did specifically remove the packages.config workaround as it was no longer necessary for Visual Studio 15.7.x. I tested initially on 15.7.1 or 15.7.2, and today I'm still seeing it work with 15.7.3.

Did you upgrade any packages or make any other changes, or ran the build from unmodified source?

[alexdrl]

@cwrea The only thing that I do is to extract the zip downloaded from GitHub, and build+run the Project in VS.
I ran the Project in an Android 4.4 virtual phone, if that matters.

I confirm that the versions of VS and Xamarin.Android SDK are the same that you mention

Doing this solves the problem https://github.com/xamarin/xamarin-android/issues/1196#issuecomment-368218787

[cwrea]

@alexdrl In that case, I suggest you open a new issue. Attach a copy of the zip file to your issue, your machine config, your build logs, etc. as described in the new issue template.