fix(runtime)!: configure grain context before construction - #10565

test/Orleans.Core.Tests/Runtime/GrainContextActivatorTests.cs:43

• The IConfigureGrainContextProvider.TryGetConfigurator contract uses a nullable out parameter annotated with [NotNullWhen(true)]. The current signature omits the attribute and uses a non-nullable out parameter, which can produce nullability-mismatch warnings (often treated as errors in this repo).

        public bool TryGetConfigurator(GrainType grainType, GrainProperties properties, out IConfigureGrainContext configurator)
        {
            configurator = new TestConfigureGrainContext(events);
            return true;
        }

test/Orleans.Runtime.Tests/GrainActivatorTests.cs:172

• The assignability check is reversed: grainClass.IsAssignableFrom(typeof(ExplicitlyRegisteredSimpleDIGrain)) will be false when grainClass is a derived type, so the configurator won't be applied to derived grain implementations. Use typeof(ExplicitlyRegisteredSimpleDIGrain).IsAssignableFrom(grainClass) instead.

                if (grainClassMap.TryGetGrainClass(grainType, out var grainClass)
                    && grainClass.IsAssignableFrom(typeof(ExplicitlyRegisteredSimpleDIGrain)))
                {

src/Orleans.Runtime/Activation/ActivationDataActivatorProvider.cs:89

• RunSynchronously will inline the activation task when the scheduler allows it, causing grain construction to happen synchronously during CreateContext instead of being enqueued asynchronously (the prior behavior) and can block the caller for the duration of grain construction. To preserve async activation while still ensuring configurators run first, start the task on the activation scheduler instead of running it synchronously.

                    task.RunSynchronously(context.ActivationTaskScheduler);

test/Orleans.Runtime.Tests/GrainActivatorTests.cs:172

• This type check is hard to read and easy to misinterpret: grainClass.IsAssignableFrom(typeof(ExplicitlyRegisteredSimpleDIGrain)) effectively behaves like an exact-type match given that GrainClassMap returns the concrete implementing type. If the intent is to match only ExplicitlyRegisteredSimpleDIGrain, an explicit equality check is clearer and avoids ambiguity about derived types.

                if (grainClassMap.TryGetGrainClass(grainType, out var grainClass)
                    && grainClass.IsAssignableFrom(typeof(ExplicitlyRegisteredSimpleDIGrain)))
                {

test/Orleans.Core.Tests/Runtime/GrainContextActivatorTests.cs:30

• The nullability of the out parameter in this TryGet implementation doesn’t match IGrainContextActivatorProvider.TryGet(..., out IGrainContextActivator?), which can produce CS8767 warnings (and may fail builds if warnings are treated as errors). Update the signature to use a nullable out parameter to match the interface.

        public bool TryGet(GrainType grainType, out IGrainContextActivator result)

test/Orleans.Core.Tests/Runtime/GrainContextActivatorTests.cs:39

• The nullability of the out parameter in this TryGetConfigurator implementation doesn’t match IConfigureGrainContextProvider.TryGetConfigurator(..., out IConfigureGrainContext?), which can produce CS8767 warnings (and may fail builds if warnings are treated as errors). Update the signature to use a nullable out parameter to match the interface.

        public bool TryGetConfigurator(GrainType grainType, GrainProperties properties, out IConfigureGrainContext configurator)

test/Orleans.Runtime.Tests/GrainActivatorTests.cs:172

• This IsAssignableFrom check is reversed. grainClass.IsAssignableFrom(typeof(ExplicitlyRegisteredSimpleDIGrain)) will fail if grainClass is a derived type/proxy of ExplicitlyRegisteredSimpleDIGrain (since derived types are not assignable from their base). Use typeof(ExplicitlyRegisteredSimpleDIGrain).IsAssignableFrom(grainClass) instead to reliably match the intended grain type.

                if (grainClassMap.TryGetGrainClass(grainType, out var grainClass)
                    && grainClass.IsAssignableFrom(typeof(ExplicitlyRegisteredSimpleDIGrain)))
                {