fix: Non-Nullable String empty query parameter

src/Http/Wolverine.Http.Tests/Bugs/Bug_1924_NonNullableEmptyQueryParameter.cs

@@ -0,0 +1,60 @@
+using Alba;
+using IntegrationTests;
+using Marten;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.DependencyInjection;
+using Wolverine.Marten;
+
+namespace Wolverine.Http.Tests.Bugs;
+
+public class Bug_1924_NonNullableEmptyQueryParameter
+{
+    [Fact]
+    public async Task non_nullable_empty_string_query_parameters_dont_throw()
+    {
+        var builder = WebApplication.CreateBuilder([]);
+
+        builder.Services.AddMarten(opts =>
+        {
+            // Establish the connection string to your Marten database
+            opts.Connection(Servers.PostgresConnectionString);
+            opts.DisableNpgsqlLogging = true;
+        }).IntegrateWithWolverine();
+
+        builder.Host.UseWolverine(opts =>
+        {
+            opts.Discovery.DisableConventionalDiscovery().IncludeType<Bug1924Controller>();
+            opts.ApplicationAssembly = GetType().Assembly;
+        });
+
+        builder.Services.AddWolverineHttp();
+
+        // This is using Alba, which uses WebApplicationFactory under the covers
+        await using var host = await AlbaHost.For(builder, app => { app.MapWolverineEndpoints(); });
+
+        await host.Scenario(x =>
+        {
+            x.Get.Url("/bugs/1924/nullable?first=Test");
+            x.StatusCodeShouldBe(200);
+            x.ContentShouldBe("Test");
+        });
+
+        await host.Scenario(x =>
+        {
+            x.Get.Url("/bugs/1924/nullable");
+            x.StatusCodeShouldBe(200);
+            x.ContentShouldBe("");
+        });
+    }
+}
+
+public class Bug1924Controller
+{
+    [WolverineGet("/bugs/1924/nullable", Name = "Bug1924_nullable")]
+    public string Get([FromQuery] string first)
+    {
+        if (first == null) throw new ArgumentNullException(nameof(first));
+        return first.ToString();
+    }
+}

src/Http/Wolverine.Http/CodeGen/IReadHttpFrame.cs

@@ -109,7 +109,7 @@ private void writeStringValue(ISourceWriter writer, GeneratedMethod method)
     {
         var assignTo = Mode == AssignMode.WriteToVariable ? $"var {Variable.Usage}" : _property;
 
-        writer.Write($"{assignTo} = {rawValueSource()};");
+        writer.Write($"{assignTo} = {rawValueSource()}?.ToString() {(_isNullable ? "" : "?? \"\"")};");
 
         if (_source == BindingSource.RouteValue)
         {