I believe I’ve exhausted the answers and comments on SO related to this topic. Full source code for the project I used to demonstrate the problem can be found here: https://github.com/jchristn/DependencyExample

Assume there is a solution with three projects. The first is a console app (Runner) with dependency on RestWrapper v3.0.19. The second is a class library (Module1) with dependency on RestWrapper v3.0.20. The third is a class library (Module2) with dependency on RestWrapper v3.0.18.

All three of these attempt to perform an HTTP GET to a user-specified URL that is retrieved in Runner. Runner then uses AssemblyLoadContext, LoadFromAssemblyPath, Resolving, and Activator.CreateInstance to create and invoke the Process method within Runner1 and then Runner2, which perform the same HTTP GET, e.g.

Instantiating the modules

AssemblyLoadContext ctx1 = new AssemblyLoadContext("module1", false);
Assembly asm1 = ctx1.LoadFromAssemblyPath(Path.GetFullPath("module1/Module1.dll"));

ctx1.Resolving += (ctx, assemblyName) =>
{
    Console.WriteLine("| Module 1 loading assembly " + assemblyName.FullName);
    var parts = assemblyName.FullName.Split(',');
    string name = parts[0];
    var version = Version.Parse(parts[1].Split('=')[1]);
    string filename = new FileInfo(Path.GetFullPath("module1/" + name + ".dll")).FullName;
    Console.WriteLine("| Module 1 loading from file " + filename);

    Assembly asm = Assembly.LoadFrom(filename);
    Console.WriteLine("| Module 1 loaded assembly " + filename);
    return asm;
};

Type type1 = asm1.GetType("Module1.Processor", true);
dynamic instance1 = Activator.CreateInstance(type1);
instance1.Process(url);

Simple RESTful Request

using (RestRequest req = new RestRequest(url))
{
    using (RestResponse resp = req.Send())
    {
        Console.WriteLine("| Status (runner) : " + resp.StatusCode + " " + resp.ContentLength + " bytes");
    }
}

I’ve operated under the assumption that by having these loaded in separate AssemblyLoadContexts with their own Resolving function that they would be able to load these differing versions, but it fails with an System.IO.FileLoadException: Could not load file or assembly 'RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null'. Could not find or load a specific file. (0x80131621) exception when attempting to run Runner1.

Console Output

C:CodeMiscDependencyExampleRunnerbinDebugnet8.0>runner

URL: https://www.google.com
| Status (runner) : 200 57841 bytes
| Module 1 loading assembly RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null
| Module 1 loading from file C:CodeMiscDependencyExampleRunnerbinDebugnet8.0module1RestWrapper.dll
System.IO.FileLoadException: Could not load file or assembly 'RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null'. Could not find or load a specific file. (0x80131621)
File name: 'RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null'
 ---> System.IO.FileLoadException: Could not load file or assembly 'RestWrapper, Version=3.0.20.0, Culture=neutral, PublicKeyToken=null'.
   at System.Runtime.Loader.AssemblyLoadContext.LoadFromAssemblyPath(String assemblyPath)
   at System.Reflection.Assembly.LoadFrom(String assemblyFile)
   at DependencyExample.Program.<>c.<Main>b__0_0(AssemblyLoadContext ctx, AssemblyName assemblyName) in C:CodeMiscDependencyExampleRunnerProgram.cs:line 49
   at System.Runtime.Loader.AssemblyLoadContext.GetFirstResolvedAssemblyFromResolvingEvent(AssemblyName assemblyName)
   at System.Runtime.Loader.AssemblyLoadContext.ResolveUsingEvent(AssemblyName assemblyName)
   at System.Runtime.Loader.AssemblyLoadContext.ResolveUsingResolvingEvent(IntPtr gchManagedAssemblyLoadContext, AssemblyName assemblyName)
   at Module1.Processor.Process(String url)
   at System.Dynamic.UpdateDelegates.UpdateAndExecuteVoid2[T0,T1](CallSite site, T0 arg0, T1 arg1)
   at DependencyExample.Program.Main(String[] args) in C:CodeMiscDependencyExampleRunnerProgram.cs:line 56

I’ve uploaded the full source (intentionally leaving out a .gitignore) at the link above. The bin/Debug/net8.0 output of Module1 and Module2 are copied into subdirectory module1/ and module2/ in the Runner‘s bin/Debug/net8.0 directory.

Also, another wrinkle to the problem, is that I need to run this on both Ubuntu and Windows.

Any help would be really appreciated!