Cross-Assembly Handlers

Header

• ID: analyzers.cross-assembly-handler-name
• Diagnostic: LB1012 (Warning)
• Maturity: GA
• Summary: Warns when handler simple names are duplicated across different assemblies, which can cause ambiguous or duplicate registration through assembly scanning.

Trigger Conditions

LB1012 reports when:

• Handler registrations are collected from source and eligible referenced assemblies.
• Two or more registrations share the same handler simple name (HandlerType.Name).
• Those registrations come from different assemblies.

The warning is name-based, not full type identity based.

Bad Example

// AssemblyA
public sealed class SharedHandlerName : ICommandHandler<CommandA> { ... }

// AssemblyB
public sealed class SharedHandlerName : ICommandHandler<CommandB> { ... }

Expected diagnostic:

• LB1012 for SharedHandlerName with both assembly names in the message.

Good Example

public sealed class BillingCreateOrderHandler : ICommandHandler<CreateOrderCommand> { ... }
public sealed class FulfillmentCreateShipmentHandler : ICommandHandler<CreateShipmentCommand> { ... }

Distinct handler names avoid false composition matches during scan-based registration.

Suppression Guidance

• Prefer unique, domain-specific handler names per assembly.
• If duplicate names are intentional, avoid broad assembly scanning or isolate registration scopes.
• Suppress only when registration paths are deterministic and reviewed.

Test Coverage

Source: tests/LiteBus.Analyzers.UnitTests/DuplicateHandlerAcrossAssembliesAnalyzerTests.cs