Multiple native dependencies are not copied to temporary storage when LoadInMemory=true

Describe the bug NuGet packages such as Confluent.SchemaRegistry.Serdes.Avro that contains multiple native dependencies seems missing native libraries in temporary storage with enabled in-memory loading/unloading. Only the main library is being copied which cause DllNotFoundException in the application.

To Reproduce

1. Add Confluent.SchemaRegistry.Serdes.Avro to a library project
2. Publish the library with the following code executed from the entry point of the application:

var config = new ProducerConfig { BootstrapServers = "localhost:9092" };

using (var p = new ProducerBuilder<Null, string>(config).Build()) {
	try {
		var dr = await p.ProduceAsync("test-topic", new Message<Null, string> { Value="test" });
		Console.WriteLine($"Delivered '{dr.Value}' to '{dr.TopicPartitionOffset}'");
	}

	catch (ProduceException<Null, string> e) {
		Console.WriteLine($"Delivery failed: {e.Error.Reason}");
	}
}

1. Load the library with enabled in-memory loading/unloading: var loader = PluginLoader.CreateFromAssemblyFile(assembly, config => { config.DefaultContext = assembliesContext; config.IsUnloadable = true; config.LoadInMemory = true; });

Expected behavior All relevant native libraries from *.deps.json should persist in temporary storage and loaded along with the main library.

[natemcmaster]

Thanks for the details. This looks to me like you’ve hit the edge of what we can reasonably support in the DotNetCorePlugins library and the “LoadInMemory” feature. I haven’t set up a full repro to verify my hunch, but here it is: it seems this callback is not invoked https://github.com/natemcmaster/DotNetCorePlugins/blob/452f8d306ef17c84c8b02b948e93eb95ef182be3/src/Plugins/Loader/ManagedLoadContext.cs#L210.

This could be because there are native <> native calls happening within the unmanaged dlls, so the AssemblyLoadContext is not called to help load. Or, it could because copying the native assembly to a new place breaks something the .NET runtime runtime.

Either way, it looks like a legit bug. I’m going to mark as “help wanted” since at this point this project is in maintenance mode and am not planning to tackle this bug myself.

[github-actions[bot]]

Closing due to inactivity. If you are looking at this issue in the future and think it should be reopened, please make a commented here and mention natemcmaster so he sees the notification.