Error getting generic grain when using a prefix

[jsteinich]

Given the following types:

interface IGenericGrain<TRequest, TResponse>{}

class ConcreteGrain : IGenericGrain<RequestType, ResponseType>{}

this call will fail to find the grain:

GrainFactory.GetGrain<IGenericGrain<TRequest, TResponse>>(myKey, "ConcreteGrain")

Omitting the prefix does work (if only one type)

GrainFactory.GetGrain<IGenericGrain<TRequest, TResponse>>(myKey)

In 7.1.2 the first call worked successfully, but in 8.2 it no longer works. (I haven't tried any version in-between)

I debugged a bit and

orleans/src/Orleans.Core/Core/GrainInterfaceTypeToGrainTypeResolver.cs

Line 36 in 6905fa9

public GrainType GetGrainType(GrainInterfaceType interfaceType, string prefix)

has a pretty different flow (in regards to a cache lookup failure) between the two calls.
The cache seems to only have an entry for IGenericGrain<RequestType, ResponseType> and not for IGenericGrain<TRequest, TResponse>; however, the result of

orleans/src/Orleans.Core/Core/GrainInterfaceTypeToGrainTypeResolver.cs

Line 48 in 6905fa9

lookupType = genericInterface.GetGenericGrainType().Value;

is the generic type which causes the cache lookup to fail.

Perhaps the lookup failing is fine and it should have something similar to the other flow, but I'm not familiar enough to say:

orleans/src/Orleans.Core/Core/GrainInterfaceTypeToGrainTypeResolver.cs

Line 139 in 6905fa9

else if (GenericGrainInterfaceType.TryParse(interfaceType, out var genericInterface) && genericInterface.IsConstructed)