Could not load file or assembly System.CodeDom

[swASO]

Describe the bug
I Updated from 0.3.1-beta to 0.5-beta and we got a exception in all our services ( linux/windows )

System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types.
Could not load file or assembly 'System.CodeDom, Version=4.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'. The system cannot find the file specified.
Could not load file or assembly 'System.CodeDom, Version=4.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'. The system cannot find the file specified.
   at System.Reflection.RuntimeModule.GetTypes(RuntimeModule module)
   at System.Reflection.RuntimeModule.GetTypes()
   at System.Reflection.Assembly.GetTypes()
   at flowfact.services.attributes.ServiceRegister.<>c__DisplayClass3_0.<FindTypesByAttribute>b__1(Assembly s)
   at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
   at System.Linq.Enumerable.SelectManySingleSelectorIterator2.ToList()
   at flowfact.services.attributes.ServiceRegister.FindTypesByAttribute(Type[] types)
System.IO.FileNotFoundException: Could not load file or assembly 'System.CodeDom, Version=4.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'. The system cannot find the file specified.
File name: 'System.CodeDom, Version=4.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'
System.IO.FileNotFoundException: Could not load file or assembly 'System.CodeDom, Version=4.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'. The system cannot find the file specified.

File name: 'System.CodeDom, Version=4.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'

Runtime environment (please complete the following information):

• Instrumentation mode: manual
• Tracer version: 0.5.0-beta
• OS: Linux / Docker image ( microsoft/dotnet:2.1-runtime-deps-stretch-slim )
• CLR: .Net Core 2.1

Additional context
i dont know what the exact problem is, but i think this lines below does produce the error
with 0.3.1-beta everythings works fine ( already did the downgrade ), with 0.5-beta i can reproduce the exception above

private static List<(Type Type, object[] CustomAttributes)> FindTypesByAttribute(params Type[] types)
{
    try
    {
        var allTypes = AppDomain.CurrentDomain.GetAssemblies()
            .Where(s => !s.FullName.StartsWith("Microsoft") && !s.FullName.StartsWith("System."))
            .Select(s => s.GetTypes()
                .Select(type => (Type: type, CustomAttributes: type.GetCustomAttributes(true)))
                .Where(z => z.CustomAttributes.Length > 0 && z.CustomAttributes.Any(t => types.Any(i => i == t.GetType())))
            );

        return allTypes.SelectMany(s => s).ToList();
    }
    catch (Exception ex)
    {
        Logger.Error(ex);
    }
    return null;
}

[lucaspimentel]

Thanks for reporting this, @swASO. To narrow down the issue to a specific release, can you test with release 0.4.1? That was the last release before 0.5.0.

[swASO]

v0.5.0 -> 👎
v0.4.1 -> 👎
v0.4.0 -> 👎
v0.3.2 -> 👍
v0.3.1 -> 👍

[lucaspimentel]

@swASO: Thanks for the code sample. We were able to reproduce the issue.

[lucaspimentel]

It looks like the error is caused by a MsgPack.Cli dependency. In v0.4.0, we updated the MsgPack.Cli NuGet reference from 0.9.2 to 1.0.0 (see #158). MsgPack.Cli has a reference to System.CodeDom 4.4.0 which is not included in the nuspec file, so it doesn't show up in their NuGet package.

This issue in their repo seems to be related.

In the short term, you can avoid the exception by skipping the MsgPack assembly in the LINQ query:

var allTypes = AppDomain.CurrentDomain
                        .GetAssemblies()
                        .Where(s => !s.FullName.StartsWith("Microsoft") &&
                                    !s.FullName.StartsWith("System.") &&
                                    !s.FullName.StartsWith("MsgPack"))   // skip MsgPack
                        .Select(s => s.GetTypes()

[lucaspimentel]

You can repro the issue with minimal code and no reference to Datadog assemblies:

string assemblyString = "MsgPack, Version=1.0.0.0, Culture=neutral, PublicKeyToken=a2625990d5dc0167";
Type[] types = Assembly.Load(assemblyString).GetTypes();

[lucaspimentel]

I created this PR so it can be fixed in the next release of their library.

[swASO]

workaround works! thanks

[lucaspimentel]

I'm closing this since there is nothing else for us to do.