Analyzers

LiteBus.Analyzers ships Roslyn rules that catch handler registration mistakes, durable contract gaps, and inbox misuse at compile time. Reference the package from application and test projects that use LiteBus mediators or durable writers.

<PackageReference Include="LiteBus.Analyzers" PrivateAssets="all" />

Analyzers have no runtime dependency on LiteBus libraries.

Rule Inventory (LB1001-LB1017)

ID	Severity	Category	Summary
LB1001	Error	Handlers	Duplicate `ICommandHandler<TCommand>` for the same command type
LB1002	Reserved	Handlers	Not implemented. Event multicast is supported, so duplicate event handlers are not reported by this rule.
LB1003	Warning	Handlers	Query or stream query handler depends on command, event, inbox, or outbox APIs
LB1004	Error	Inbox	`ICommand<TResult>` passed to `IInbox.AcceptAsync`, `AcceptBatchAsync`, or `ITransactionalInbox.AcceptAsync`
LB1005	Error	Handlers	Open generic handler exposes unsupported generic arity
LB1007	Warning	Contracts	Handled durable command/event lacks `[MessageContract]` and explicit `Contracts.Register` / `RegisterFromAssembly`
LB1008	Error	Handlers	Command type has no main command handler in the compilation
LB1009	Error	Handlers	Query or stream query type has no main handler in the compilation
LB1010	Error	Handlers	Duplicate `IQueryHandler<TQuery, TResult>` or `IStreamQueryHandler<TQuery, TResult>` for the same query type
LB1011	Warning	Handlers	`[HandlerTag]` is not referenced by command, query, or event mediation tag filters
LB1012	Warning	Handlers	Same handler simple name appears in multiple assemblies (risk of double `RegisterFromAssembly`)
LB1013	Warning	Outbox	Constructor injects `ITransactionalOutboxStore` without a `DbContext` in the same constructor
LB1014	Error	Configuration	Inbox or outbox processor enabled without a dispatcher in the same module builder scope
LB1015	Warning	Configuration	Transactional EF storage calls `EnforceTransactionalSetup()` without `EnableSaveChangesInterceptor()`
LB1016	Warning	Inbox	Constructor injects `ITransactionalInboxStore` without a `DbContext` in the same constructor
LB1017	Warning	Contracts	Type declares `[MessageContract]` but lacks explicit `Contracts.Register` or `RegisterFromAssembly` in the compilation

Contract Registration Split (LB1007 vs LB1017)

LB1007 fires on handled durable types that have neither [MessageContract] nor registration discovered through Contracts.Register<T>() or RegisterFromAssembly.
LB1017 fires on attributed durable types that lack explicit registration. Runtime on-demand resolution still works; explicit registration is recommended for predictable discovery.

Both rules treat RegisterFromAssembly / AddFromAssembly as satisfying explicit registration. LB1017 matches only IContractWriter / IMessageContractRegistry Register invocations, not unrelated Register<T>() methods.

Inbox Result Commands (LB1004)

The inbox replays stored commands later and discards handler results. Only result-less ICommand types may be accepted. LB1004 covers AcceptAsync, AcceptBatchAsync (including InboxAcceptItem.From in array and collection-expression batches), and transactional inbox acceptance APIs.

Query and Stream Query Handlers (LB1009 and LB1010)

LB1009 reports query types without IQueryHandler<TQuery, TResult> and stream query types without IStreamQueryHandler<TQuery, TResult>. Stream queries implementing IStreamQuery<TResult> are not checked against query handlers. LB1010 applies the same duplicate detection to both handler kinds. Message type discovery for LB1008, LB1009, and LB1010, and handler registration scanning, include eligible referenced assemblies (same filter as handler registration scanning).

Reserved Event Handler Slot (LB1002)

LB1002 is intentionally unused in the shipped analyzer set. Event mediation supports multiple handlers for one event type, so the command and query duplicate rules do not have an event equivalent. LB1012 still warns when the same handler simple name appears in multiple assemblies.

Suppression

Use #pragma warning disable LB1007 (or the relevant ID) sparingly. Prefer fixing registration or handler shape.