Backport of #35791 to release/6.0-rc1

/cc @halter73

Customer Impact

Before rc1, customers who wanted to advanced parameter binding with minimal API giving full access to the request's HttpContext, could not do so.

In rc1, we added support for parameter binding via a public static BindAsync method on the parameter's declaring type:

public static ValueTask<object?> BindAsync(HttpContext context);

The big thing it's missing is details about the parameter other than the type like the parameter's name and attributes, so we decided to add a ParameterInfo argument to BindAsync. We also decided that it would be better to require the return type to be ValueTask<{DeclaringType}> instead of ValueTask<object?> for better type-safety.

So after this change, we will not look for the old BindAsync signature on the parameter's declaring type, but instead the following:

public static ValueTask<{DeclaringType}> BindAsync(HttpContext context, ParameterInfo parameter);

Before:

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();

app.MapGet("/webhook", (CloudEvent cloudEvent) =>
{
    redis.Publish(cloudEvent);
});

app.Run();

public class CloudEvent
{
    public static async ValueTask<object?> BindAsync(HttpContext context)
    {
        return await CloudEventParser.ReadEventAsync(context);
    }
}

After:

public class CloudEvent
{
    public static async ValueTask<CloudEvent?> BindAsync(HttpContext context, ParameterInfo parameter)
    {
        return await CloudEventParser.ReadEventAsync(context, parameter.Name);
    }
}

We don't want to have a breaking change between rc1 and rc2 which is why we're asking to get this change in rc1 now.

Regression?

• Yes
• No

Packaging changes reviewed?

• Yes
• No
• N/A

Verification

• Manual (required)
• Automated

Risk

• High
• Medium
• Low

Support for BindAsync is entirely new in rc1.