Modify Serilog:Using section check to be less restrictive

src/Serilog.Settings.Configuration/Settings/Configuration/ConfigurationReader.cs

@@ -383,7 +383,7 @@ static IReadOnlyCollection<Assembly> LoadConfigurationAssemblies(IConfiguration
             assemblies.Add(assumed);
         }
 
-        if (assemblies.Count == 1)
+        if (assemblies.Count == 1 && !UsingSectionExists())
         {
             var message = $"""
                 No {usingSection.Path} configuration section is defined and no Serilog assemblies were found.
@@ -396,6 +396,11 @@ This is most likely because the application is published as single-file.
         }
 
         return assemblies;
+
+        // https://github.com/serilog/serilog-settings-configuration/issues/389
+        bool UsingSectionExists() =>
+            // usingSection.Exists() alas, see https://github.com/dotnet/runtime/issues/58104
+            section.GetChildren().Any(e => e.Key == "Using");
     }
 
     void CallConfigurationMethods(ILookup<string, Dictionary<string, IConfigurationArgumentValue>> methods, IReadOnlyCollection<MethodInfo> configurationMethods, object receiver)

test/Serilog.Settings.Configuration.Tests/LoggerConfigurationExtensionsTests.cs

@@ -1,6 +1,7 @@
 using Microsoft.Extensions.Configuration;
 using Serilog.Events;
 using Serilog.Settings.Configuration.Tests.Support;
+using TestDummies;
 
 namespace Serilog.Settings.Configuration.Tests;
 
@@ -84,6 +85,29 @@ public void ReadFromConfigurationSectionThrowsWhenTryingToCallConfigurationMetho
 
     }
 
+    [Fact]
+    public void ReadFromConfigurationDoesNotThrowWithEmptyUsingSection()
+    {
+        // language=json
+        var json = """
+            {
+                "Serilog": {
+                    "Using": [],
+                    "MinimumLevel": "Debug"
+                }
+            }
+            """;
+
+        var config = new ConfigurationBuilder()
+            .AddJsonString(json)
+            .Build();
+
+        _ = new LoggerConfiguration()
+               .ReadFrom.Configuration(config)
+               .WriteTo.DummyConsole()
+               .CreateLogger();
+    }
+
     [Fact]
     public void ReadFromConfigurationDoesNotThrowWhenTryingToCallConfigurationMethodWithIConfigurationParam()
     {