Message and Handler Type Registry

• ID: runtime.message-registry
• Name: Message and handler type registry
• Maturity: GA
• Summary: Registers message and handler CLR types, builds descriptors, and supports open-generic handler expansion.

What It Does

MessageRegistry implements IMessageRegistry (IMessageWriter and IMessageReader). It keeps exact message descriptor lookup, ordered handler descriptors, and open-generic handler templates that are closed against concrete messages.

Public Surface

Packages

• LiteBus.Messaging
• LiteBus.Messaging.Abstractions

Requires

• runtime.handler-descriptors
• runtime.message-resolution

Invariants

• Duplicate type registration is idempotent.
• Generic message types are normalized for lookup.
• Unsupported open-generic handler shapes fail fast.

Non-Goals

• Persisted registry storage.

Observability

No dedicated telemetry.

Test Coverage

Covered Use Cases

MessageRegistryTests.Register_OpenGenericHandler_ShouldLinkToExistingConcreteMessageType

• Test kind: Unit
• Expected outcome: open generic handler is closed and linked

MessageRegistryTests.Register_ConcreteMessageAfterOpenGenericHandler_ShouldLinkOpenGenericHandler

• Test kind: Unit
• Expected outcome: later concrete message receives closed handler

MessageRegistryTests.Find_ExactType_ShouldReturnDescriptorInConstantTime

• Test kind: Unit
• Expected outcome: exact descriptor lookup works

Untested Use Cases

Out-of-Scope Use Cases

• Open-generic handlers with multiple type parameters.