FileLoadException on IServiceCollection.AddReact()

[TomGroeneboer]

Hi guys,

I've encountered an issue when adding React to a project. If I try to do services.AddReact() in the ConfigureServices method in the Startup class it throws a FileLoadExeption with the following details:
Could not load file or assembly 'React, Version=1.5.0.0, Culture=neutral, PublicKeyToken=9aed67b161f7db78' or one of its dependencies. A strongly-named assembly is required. (Exception from HRESULT: 0x80131044)


Does someone know why this happens and how I can resolve it?

I'm running CLR-x86-beta6 in Visual Studio 2015.

Thanks!

[davidfowl]

That's a good question. Do you have repro steps?

[TomGroeneboer]

Just create an empty application with ASP.NET 5, add React following these steps.
Note: The services.UseRequestServices() doesn't work, I think it's depricated?

If you try to run the application it comes up with the error :(

[davidfowl]

Those instructions are based on very old versions of ASP.NET 5. Have you contacted them to ask if they have newer versions that are compatible with newer betas of ASP.NET 5.

[TomGroeneboer]

There seems to be an update on NuGet but I can't download it in VS, it only states that version 1.5.3 (and lower) is available...

//// update:
I managed to install version 1.5.4, but it still gives me the FileLoadException...

[Daniel15]

Bumping this because I just got another report of it (also see reactjs/React.NET#153). The exception looks like the following:

---

System.IO.FileLoadException was unhandled by user code
FileName=React, Version=1.5.0.0, Culture=neutral, PublicKeyToken=9aed67b161f7db78
FusionLog=""
HResult=-2146234300
Message=Could not load file or assembly 'React, Version=1.5.0.0, Culture=neutral, PublicKeyToken=9aed67b161f7db78' or one of its dependencies. A strongly-named assembly is required. (Exception from HRESULT: 0x80131044)
Source=React.AspNet
StackTrace:
at React.AspNet.ReactServiceCollectionExtensions.AddReact(IServiceCollection services)

---

The strange thing is that the "React" assembly is strong-named. React.AspNet has a dependency on React.Core which contains React.dll, and I've verified that the latest version does indeed have the correct strong name. Note that ReactJS.NET does not support .NET Core at the moment, so this is only using dnx451.

I haven't been able to replicate the issue myself, everything works as expected for me 😟

Any ideas what's going on here?

Those instructions are based on very old versions of ASP.NET 5. Have you contacted them to ask if they have newer versions that are compatible with newer betas of ASP.NET 5.

The latest version of ReactJS.NET was built against beta6, I'll release an update for beta7 soon. The instructions were outdated but I updated them a while ago.

[davidfowl]

If you could provide a sample application that has the error that would be great. Can one of your users provide that info?

[Daniel15]

The two people that have reported it so far are @TomGroeneboer (who originally reported this issue) and @jongalloway (who reported it earlier today).

@jongalloway are you able to provide a sample app that exhibits the issue?

[jongalloway]

Repro is here: https://github.com/jongalloway/react-js-net-repro

All I did was:

1. File / New / MVC 6 (beta7)
2. Follow the steps here http://reactjs.net/getting-started/aspnet5.html
3. Run

[Daniel15]

Ahh, I see. The issue is that your web project is called "React", but the core ReactJS.NET assembly is also called "React" 😆 I think the assembly loader gets confused and tries to load your site's assembly rather than the ReactJS.NET assembly. This fails because the assembly React.AspNet referenced at build time was strongly-named, and the strong name doesn't match. If I rename your project from "React" to "Reactizzle", I don't get the strong typing error any more (I do get a different unrelated error, which is because the latest release of ReactJS.NET was build against beta6 rather than beta7. The latest master version does support beta 7).

I tried the same thing with ASP.NET 4.5 + MVC 5, and the error is the one I would have expected: "Could not load file or assembly 'React, Version=1.5.0.0, Culture=neutral, PublicKeyToken=9aed67b161f7db78' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. " In this case the assembly bind log shows more details that help to debug the issue:

LOG: Attempting download of new URL file:///c:/users/danlo/documents/visual studio 2015/Projects/ReactBug/React/bin/React.DLL.
WRN: Comparing the assembly name resulted in the mismatch: Minor Version

It seems like ASP.NET 5 still tries to load the assembly even though the version number doesn't match, resulting in a more confusing error message.

[davidfowl]

We had the same problems a long time ago in signalr, then we called it Microsoft.AspNet.SignalR

[Daniel15]

@davidfowl - It may be an edge case, but can the loader guard against this somehow (a referenced assembly having the same name as the site itself)?

[davidfowl]

We don't look at strong names when loading assemblies. We could probably fail if 2 things have the same name in the graph but it's not something we're going to do in the short term.