Source Generator

Source Generator

Ships inside the NativeEndpoints package as an analyzer, so dotnet add package NativeEndpoints brings it along. Nothing to configure.

What it generates

An explicit registration naming every endpoint class in your assembly:

// generated
public static class BillingEndpoints
{
    public static EndpointGroup Map(this EndpointGroup group, string? routePrefix = null)
    {
        group.MapEndpoint<Billing.Endpoints.Invoices.Get.Endpoint>(routePrefix);
        group.MapEndpoint<Billing.Endpoints.Invoices.Create.Endpoint>(routePrefix);
        // ...
        return group;
    }
}

Call it instead of the reflective scan:

using NativeEndpoints.Generated;

app.MapEndpointGroup().Map(routePrefix: "/api");

The class is named after your assembly, so two assemblies in one host do not collide.

Both paths produce identical endpoints, which the test suite pins by mapping the same assembly each way and comparing. The reflective MapEndpointsFrom is not going away: it is the documented fallback for anyone who cannot run the generator.

What it tells you at build time

Rule	Meaning
NE0001	Endpoint declares no route attribute, and the generator cannot see whether Configure supplies one
NE0002	A contract parameter has a type the binder cannot produce from a request string
NE0003	Configure reads constructor-injected state, which is null at map time
NE0004	A contract has more than one public constructor, so the binder will throw when the route is first called

NE0002 is the one that earns the generator its place. Without it, a contract parameter the binder cannot convert throws on the first request that reaches the route, in whichever environment reaches it first. With it, the build says so.

It is reported only for GET and HEAD. Everywhere else a contract member may come from the JSON body, where any serializable type is fine, and Configure can change the body mode in ways the generator cannot see. Reporting there would be noise.

Registered value binders

A value binder is registered at runtime, and no analyzer can see that. Tell the build:

[assembly: EndpointValueBinder(typeof(Money))]

builder.Services.AddNativeEndpoints(o => o.ValueBinders.Add<Money>(Money.TryParse));

The attribute carries no runtime behavior. It exists so NE0002 stays quiet for a type you have deliberately taught the binder about. Without it the warning is a false positive, and in a project treating warnings as errors it is a build break for correct code.

Types implementing IParsable<T> need no declaration; the generator sees the interface.

Inside this repository

Analyzers flow to consumers through a package's analyzers/ folder, not through a ProjectReference chain. Projects in this repository that want the generator reference it directly:

<ProjectReference Include="../../src/NativeEndpoints.Generator/NativeEndpoints.Generator.csproj"
                  ReferenceOutputAssembly="false"
                  OutputItemType="Analyzer" />

Native AOT

Generated registration removes the assembly scan and the MakeGenericMethod call, which are two of the reflection paths that block trimming. Activation and binding still use reflection, so AOT is not yet supported. Generating those is the remaining work, and the API is shaped for it: the registration seam this generator already emits is where a generated binder and activator will attach.