WithDisplayName() on endpoint not working with ApiDescription with minimal actions

[martincostello]

Describe the bug

If a minimal action is configured with a display name, then the configured display name does not flow through to the ApiDescription associated with the action.

To Reproduce

Configure an endpoint action similar to the below:

builder.MapGet("/denied", () => Results.Redirect("/?denied=true"))
       .WithDisplayName("DENIED");

Then inspect the ApiDescription in the debugger, such as with the DocInclusionPredicate() when using AddSwaggerGen():

builder.Services.AddSwaggerGen(options =>
{
    options.SwaggerDoc("v1", new OpenApiInfo { Title = "API", Version = "v1" });
    options.DocInclusionPredicate(
        (_, description) => description.RelativePath?.StartsWith("api/", StringComparison.Ordinal) == true);
});

The ApiDescription.DisplayName property is null.

In the above example, the value is expected to be "DENIED".

Further technical details

• ASP.NET Core 6.0.0-preview.7.21325.3
• .NET SDK 6.0.100-preview.7.21330.1
• Visual Studio 2022 17.0.0 Preview 1.1

[martincostello]

I've worked out why this is - will push up a PR with a proposed fix.

[martincostello]

Turns out that the DisplayName is just never set, rather than only when WithDisplayName() is used.