MissingMethodException / "Method not found" after update to Moq 4.8.0

[JHotterbeekxBannerconnect]

Hi,

Today I've tried updating the NuGet package from 4.7.145.0 to 4.8.0.0 and I'm running into an issue with a specific test case failing now on a strange error message. To give you some context, in our tests we create a HttpActionContext to test our authentication. This is native .net functionality. I've isolated the issue to the following code:

[Test]
public void OnActionExecuting_ShouldFillMarketInSession() {
  var fakeActionContext = _CreateFakeHttpActionContext();
}

private HttpActionContext _CreateFakeHttpActionContext() {
  return new HttpActionContext(null, new ReflectedHttpActionDescriptor()) {
    Response = new HttpResponseMessage(HttpStatusCode.OK)
  };
}

When running this test, it fails with the following error:

System.MissingMethodException : Method not found: 'Void System.Web.Http.Controllers.HttpActionContext.set_Response(System.Net.Http.HttpResponseMessage)'.
at SMP.Api.Test.Filter.MoqTest._CreateFakeHttpActionContext()
at SMP.Api.Test.Filter.MoqTest.OnActionExecuting_ShouldFillMarketInSession() in C:\Projects\Athena\Athena\SMP.Api.Test\Filter\MoqTest.cs:line 14

Could you help me figure out what is wrong, or fix this if it is an actual bug?

Thanks,
John

[stakx]

Hi @JHotterbeekxBannerconnect and thanks for reporting. Unfortunately, I do not see anything related to Moq in your example code, so I have to wonder whether your issue is even related to Moq at all.

Could you please provide a short but complete code example that demonstrates this issue, and shows how Moq is involved? (Otherwise I'll close this issue in a couple of days' time.) Thank you!

(Btw. MissingMethodExceptions usually indicate that you have old DLLs lurking around somewhere that are not binary-compatible with the version against which your code was compiled. Try deleting your project's obj and bin folders, your test runner's cache (if applicable), and possibly also your project's or user profile's NuGet package cache.)

[willykc]

Hi, I think I'm seeing the same problem. Out of 405 tests using Moq, 16 started failing after upgrading to Moq 4.8.0 with exception "System.MissingMethodException: Method not found". It seems to be related to the "System.Net.Http" namespace since all the "missing methods" in the failing tests have types from that namespace in their signature (eg. "System.Net.Http.HttpResponseMessage").

[stakx]

@JHotterbeekxBannerconnect, @willykc: Could it be that you updated not just Moq, but any other Microsoft ASP.NET packages at the same time without noticing it? Because quite frankly, Moq has no dependency on, nor any special logic related to, any System.Net.Http.* types. I don't see how this issue could be caused by Moq, especially when the MissingMethodException gets triggered in a piece of code that doesn't even involve Moq.

[JHotterbeekxBannerconnect]

We've updated several packages, but saw tests failing. So I reverted everything and updated one by one, everything keeps working until the last package is updated, which is Moq. But I'm going to try cleaning old DLL's and cache and see what that does, and if it still doesn't work try a new solution to reproduce this.

[stakx]

@JHotterbeekxBannerconnect: That's truly strange. Until you have repro code ready to share, could you perhaps give the following information:

• What version of Visual Studio are you working with?
• What exact framework / platform are your projects targeting?
• What NuGet packages (including version numbers) are your projects referencing?
• Are you using <PackageReference>s or a NuGet packages.config?
• Are there any assembly binding redirects in your App.config or Web.config? If so, what do they look like?
• Is there a <AutoGenerateBindingRedirects> element in your root project file? If so, what is its value?

[JHotterbeekxBannerconnect]

@stakx I've been able to reproduce it in a simple test project:
Working.without.Moq.zip

When you open this (in VS 2017) you'll see that there is one single test in there. This runs without any issues. Now try adding through NuGet, you'll see that the test fails.

I've found something more interesting, when updating to the latest version of Moq through NuGet, another package seems to come along called System.Threading.Tasks.Extensions.4.4.0. This is the one that seems to be causing the error, because if I remove this as reference from the included test project, the test will succeed again.

The other info you requested (for the test solution):

• VS 2017 Professional 15.5.2 / .net v 4.7.02556
• Any CPI
• Just Moq 4.8.0
• packages.config
• None

Hopefully this is enough for you to reproduce it.

[stakx]

Thanks a lot for the test solution, and the analysis you've done already! I can now reproduce this issue.

(One problem I noticed before I could even run your tests is that your project is a missing System.Web.Http assembly. I've resolved this one by installing the Microsoft.AspNet.WebApi.Core package.)

I'll now try to find the precise cause of this.

[stakx]

OK, seems you're affected by the problem described in dotnet/standard#481, and adding the following to your MoqTests.csproj file appears to resolve the issue:

<PropertyGroup>
  <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
  <GenerateBindingRedirectsOutputType>true</GenerateBindingRedirectsOutputType>
</PropertyGroup>

(PS: Alternatively, update your project file(s) to the new SDK format, which should already implicitly include the above properties.)

The problem indeed gets triggered by System.Threading.Tasks.Extensions package (which Moq references because of ValueTask<TResult>). Note that it does not target the full .NET Framework, only .NET Standard. Referencing a .NET Standard assembly from a .NET Framework project used to not work, but support for doing just that was added in .NET 4.6.1. Unfortunately, it's a pretty flaky feature and it sometimes requires assembly binding redirects (which your test project doesn't have).

Please see the issue referenced above for details.

[JHotterbeekxBannerconnect]

@stakx Thanks a lot for the help and explanation! I've added the properties to the solution and the tests run without any issue now. Seems like something that more people could run into, maybe this should be put in the wiki somewhere?

[stakx]

@JHotterbeekxBannerconnect - I agree that this situation needs to be improved. I'm currently looking into Moq's reference of the System.Threading.Tasks.Extensions package (which was added in 2194e5f). It doesn't seem right that this package is referenced at all by the net45 target, as this framework version didn't yet allow references to .NET Standard assemblies. And then there's that issue I linked to to deal with.

Adding a warning to the wiki would be a start... would you like to do this?

Short of temporarily removing ValueTask<TResult> support in Moq for the full .NET Framework, I'm not sure how to cleanly resolve this problem. @AdamDotNet — you added the package reference to System.Threading.Tasks.Extensions to Moq a while ago. Do you by chance know how to properly deal with this kind of problem (cross-target assembly references)?

I'm also still not sure yet why just referencing that assembly caused the issue (note that your test doesn't make use of it).

[JHotterbeekxBannerconnect]

@stakx I've added it as a FAQ to the wiki, referencing to the .net standard issue and this issue. Great that you'll look in to this, I agree that it feels weird that this issue is being caused, and even stranger without actually using anything from the reference.