CHR0028: Redundant .AutoMap() call

Rule Description

AutoMap is enabled by default on projection builders, so calling .AutoMap() explicitly has no effect. Remove the redundant call. Use .NoAutoMap() when you need to disable the default behavior.

Severity

Warning

Example

C#

using Cratis.Chronicle.Events;
using Cratis.Chronicle.Projections;

public record Chr0028Product(string Name);

[EventType]
public record Chr0028ProductRegistered(string Name);

public class Chr0028ProductProjection : IProjectionFor<Chr0028Product>
{
    public void Define(IProjectionBuilderFor<Chr0028Product> builder) =>
        builder
            .From<Chr0028ProductRegistered>()
            // Warning CHR0028: '.AutoMap()' is redundant — AutoMap is enabled by default. Remove the call.
            .AutoMap();
}

Why This Rule Exists

A fluent IProjectionFor<T> projection maps each referenced event’s properties onto identically named read model properties on its own — AutoMap is on from the moment the builder starts. Calling .AutoMap() therefore only restates the default: it changes nothing and adds noise that suggests mapping is being configured when it is not.

The method exists for one narrow purpose — re-enabling AutoMap inside a scope where you first turned it off with .NoAutoMap(). Outside that scope the call is redundant. When you actually want to take control of mapping, reach for .NoAutoMap() and set the properties yourself; a bare .AutoMap() never expresses intent.

Related Rules

• CHR0029 — a .Set(...).To(...) mapping whose source and target names match, which AutoMap already handles.
• Model-bound projections — the full reference.