WebApplicationOptions.WebRootPath is ignored if a wwwroot folder exists

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

If a wwwroot folder exists, content is served from that location even though WebApplicationOptions.WebRootPath has been specified.

In my development environment, I want to serve my web app from uncompiled sources. In production, my web app is compiled into the wwwroot folder. I switch the web root path on the development environment variable as shown below. (This is the only way I could find in .NET 6, whereas before it was trivial to set the IWebHostEnvironment.WebRootPath property).

I am now forced to rename the production wwwroot folder to something else, in order to circumvent this default behaviour.

WebApplicationBuilder builder;
{
    WebApplicationOptions opts;

    if (Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT") == Environments.Development)
    {
        var path = Path.Combine(
            Directory.GetParent(Environment.CurrentDirectory.TrimEnd('\\'))!.ToString(),
            "MyWebAppDevSources");

        opts = new()
        {
            Args = args,
            WebRootPath = path,
        };
    }
    else
    {
        opts = new()
        {
            Args = args,
            WebRootPath = "webroot", // Forced to use a different location in Production,
                                     // just to avoid having requests being served from the
                                     // `wwwroot` folder in Development mode.
        };
    }

    builder = WebApplication.CreateBuilder(opts);
}

Expected Behavior

I expect the WebApplicationOptions.WebRootPath property to always take precedence even when there is a default wwwroot folder on disk.

I also wish there were a way to set this property after instantiating the WebApplicationBuilder.

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

6.0.200

Anything else?

No response

[space-alien]

Here is an ultra-minimal repro that demonstrates the problem: https://github.com/space-alien/AspNetWebRootPath

[javiercn]

Filed https://github.com/dotnet/AspNetCore.Docs/issues/25446 to improve the docs for this scenario.