ARCCHR0014: Observed event stream is not declared

Rule

Warning. A reactor or reducer carries [FromEventSource<TSource>("stream")], and the definition TSource does not declare a stream named stream with [EventStream("stream")].

A stream that the definition does not declare cannot match, so no event would reach the observer. The diagnostic is reported on the attribute.

Resolve the diagnostic

Declare the stream on the definition, or observe a stream it declares.

using Cratis.Chronicle.Events;
using Cratis.Chronicle.EventSources;
using Cratis.Chronicle.Reactors;

[EventSource("Account")]
[EventStream("Transactions")]
public class AccountEventSource : IEventSource;

[EventType]
public record TransactionRecorded(decimal Amount);

[FromEventSource<AccountEventSource>("Transactions")]
public class TransactionObserver : IReactor
{
    public Task Recorded(TransactionRecorded @event) => Task.CompletedTask;
}

Misspelling "Transactions" in the attribute, or removing the [EventStream] attribute from the definition, reports this rule.

Boundaries

Only the definition’s own attributes are read, so a definition in a referenced assembly is checked the same way as one in your project. A stream argument that is not a constant string, and a definition that is not resolved yet, are left alone. No code fix is offered.