Object Reference after updating 1.8.1 -> 1.9 (Elastic.Apm.Agent.Tracer is null)

[insanity13]

APM Agent version

Elastic.Apm 1.9.

Environment

Windows
.Net Framework 4.7.2

Describe the bug

It looks like Elastic.Apm.Agent.Tracer behavior changed in 1.9 (previously was 1.8.1)
In DEBUG mode (local execution) we don't Initialize APM.
After updating the assembly Elastic.Apm.Agent.Tracer became null

For example, we have an Object reference

1. Windows Service
   var transaction = Elastic.Apm.Agent.Tracer.StartTransaction(FullName, ApiConstants.TypeRequest);
2. WebSite in APM SQL Interceptor
   

It is not critical, I've fixed it all on our side. This Issue FYI only, feel free to close it.

[iqmeta]

Same here, new Version broke existing code.

[iqmeta]

It is not critical, I've fixed it all on our side. This Issue FYI only, feel free to close it.

What did you change for Debug? Also .NET 4.8 Framework? Here it's a Console Application.

[russcam]

Thanks for opening @insanity13. We'll need to investigate what caused this and look to fix it

[russcam]

I've put together a simple net472 console application using Elastic.Apm 1.9.0

using System;
using Elastic.Apm;

namespace ApmAgentGitHub1254
{
    class Program
    {
        static void Main(string[] args)
        {
            var transaction = Agent.Tracer.StartTransaction("foo", "bar");
            transaction.End();
        }
    }
}

But I'm unable to replicate the null reference exception. @insanity13 or @iqmeta, are you able to replicate the exception with a simple example?

[iqmeta]

I've put together a simple net472 console application using Elastic.Apm 1.9.0

using System;
using Elastic.Apm;

namespace ApmAgentGitHub1254
{
    class Program
    {
        static void Main(string[] args)
        {
            var transaction = Agent.Tracer.StartTransaction("foo", "bar");
            transaction.End();
        }
    }
}

But I'm unable to replicate the null reference exception. @insanity13 or @iqmeta, are you able to replicate the exception with a simple example?

Sure, here a project to easy reproduce..
ConsoleApp.zip

Guess it's with the Agent.Setup()

Config we use like here you do in your Tests
https://github.com/elastic/apm-agent-dotnet/blob/5db57e664e5ce41498bb3b3bfea3474dd6c95d2d/test/Elastic.Apm.EntityFramework6.Tests/Ef6Tests.cs

[insanity13]

I've debug my app it crashed on CentralConfigFetcher and MetricsCollector initialization.
So TracerInternal is not initialized.

I have

      <dependentAssembly>
        <assemblyIdentity name="System.ValueTuple" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.0.3.0" newVersion="4.0.3.0" />
      </dependentAssembly>

In my app, removed it, and it helps.

If TracerInternal initialization was earlier, or the initialization of CentralConfigFetcher would have been in the try catch, then Agent.Tracer will work.

@russcam The main reason why didn't we see the error - is the incorrect logging:
logger is null, so if it was Logger (which is initialized as ConsoleLogger) the error was logged

I think it should be fixed.

[insanity13]

Sure, here a project to easy reproduce..

Your sample works on my side (but I've changed the framework to 4.6.1 since I have no 4.6.2).

@iqmeta you can download 1.9 Source Code (https://github.com/elastic/apm-agent-dotnet/releases/tag/1.9.0)
And replace Nuget Elastic.Apm by the local built library, then you can catch the exception.
I think it'll be the fastest way to find the problem.

[iqmeta]

Sure, here a project to easy reproduce..

Your sample works on my side (but I've changed the framework to 4.6.1 since I have no 4.6.2).

@iqmeta you can download 1.9 Source Code (https://github.com/elastic/apm-agent-dotnet/releases/tag/1.9.0)
And replace Nuget Elastic.Apm by the local built library, then you can catch the exception.
I think it'll be the fastest way to find the problem.

You're right. So I did bring in the other nuget packages...

Test2.zip

Now it fails...

I try it also with the source myself.

[insanity13]

@iqmeta you got the same issue. Check your assembly bindings

      <dependentAssembly>
        <assemblyIdentity name="System.ValueTuple" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.0.3.0" newVersion="4.0.3.0" />
      </dependentAssembly>

But I'm not sure if it can be safely removed for your application.

[iqmeta]

@iqmeta you got the same issue. Check your assembly bindings

      <dependentAssembly>
        <assemblyIdentity name="System.ValueTuple" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.0.3.0" newVersion="4.0.3.0" />
      </dependentAssembly>

But I'm not sure if it can be safely removed for your application.

Yes. Thanks. Nuget Update killed it. Also think this should be fixed.

[gregkalapos]

Thanks for all the info @insanity13 and @iqmeta.

Yes. Thanks. Nuget Update killed it. Also think this should be fixed.

@iqmeta does this mean that you had the same binding redirect in place prior to updating to 1.9 and now adding it back makes it work again?

The fact that the agent initialization fails with an AssemblyLoadException due to not finding System.ValueTuple sounds valid and adding the dependency and using binding redirect is indeed a good fix. On the other hand, I see how this is related to the 1.9 release.

We had this dependency previously in 1.8.1:

[russcam]

The reference is also there in 1.9.0

[insanity13]

@russcam I apologize for the silence. I'll investigate it next week.

p.s. I hope you haven't missed my remark on the logger?

[russcam]

Thanks @insanity13, I've opened #1305 to fix

[insanity13]

I apologize for not respond as I promised.
I was unable to determine the update dependency on the error.
Agree you can close this Issue, thanks!