Removes sealed from a number of classes and respects empty strings in enummember

YamlDotNet.Analyzers.StaticGenerator/SerializableSyntaxReceiver.cs

@@ -210,7 +210,7 @@ private void HandleEnum(ITypeSymbol type)
                         if (enumMember != null)
                         {
                             var argument = enumMember.NamedArguments.FirstOrDefault(x => x.Key == "Value");
-                            if (!string.IsNullOrWhiteSpace(argument.Value.Value as string))
+                            if ((argument.Value.Value as string) != null)
                             {
                                 memberValue = (string)argument.Value.Value!;
                             }

YamlDotNet.Test/Analyzers/StaticGenerator/ObjectTests.cs

@@ -231,8 +231,8 @@ public void EnumSerializationUsesEnumMemberAttribute()
         public void EnumSerializationUsesEnumMemberAttributeWithEmptyValue()
         {
             var serializer = new StaticSerializerBuilder(new StaticContext()).Build();
-            var actual = serializer.Serialize(EnumMemberedEnum.EmptyValue);
-            Assert.Equal("EmptyValue", actual.TrimNewLines());
+            var actual = serializer.Serialize(new EnumMemberedEnumHarness { Test = EnumMemberedEnum.EmptyValue });
+            Assert.Equal("Test: ''", actual.TrimNewLines());
         }
 
         [Fact]
@@ -243,6 +243,12 @@ public void EnumSerializationUsesEnumMemberAttributeWithNullValue()
             Assert.Equal("NullValue", actual.TrimNewLines());
         }
 
+        [YamlSerializable]
+        public class EnumMemberedEnumHarness
+        {
+            public EnumMemberedEnum Test { get; set; }
+        }
+
         [YamlSerializable]
         public enum EnumMemberedEnum
         {

YamlDotNet.Test/Serialization/SerializationTests.cs

@@ -1500,8 +1500,8 @@ public void EnumSerializationUsesEnumMemberAttribute()
         public void EnumSerializationUsesEnumMemberAttributeWithEmptyValue()
         {
             var serializer = new SerializerBuilder().Build();
-            var actual = serializer.Serialize(EnumMemberedEnum.EmptyValue);
-            Assert.Equal("EmptyValue", actual.TrimNewLines());
+            var actual = serializer.Serialize(new { Test = EnumMemberedEnum.EmptyValue });
+            Assert.Equal("Test: ''", actual.TrimNewLines());
         }
 
         [Fact]

YamlDotNet/Serialization/ObjectFactories/DefaultObjectFactory.cs

@@ -32,7 +32,7 @@ namespace YamlDotNet.Serialization.ObjectFactories
     /// <summary>
     /// Creates objects using Activator.CreateInstance.
     /// </summary>
-    public sealed class DefaultObjectFactory : ObjectFactoryBase
+    public class DefaultObjectFactory : ObjectFactoryBase
     {
         private readonly Dictionary<Type, ConcurrentDictionary<Type, MethodInfo[]>> stateMethods = new()
         {

YamlDotNet/Serialization/TypeInspectors/CachedTypeInspector.cs

@@ -30,7 +30,7 @@ namespace YamlDotNet.Serialization.TypeInspectors
     /// <summary>
     /// Wraps another <see cref="ITypeInspector"/> and applies caching.
     /// </summary>
-    public sealed class CachedTypeInspector : TypeInspectorSkeleton
+    public class CachedTypeInspector : TypeInspectorSkeleton
     {
         private readonly ITypeInspector innerTypeDescriptor;
         private readonly ConcurrentDictionary<Type, List<IPropertyDescriptor>> cache = new ConcurrentDictionary<Type, List<IPropertyDescriptor>>();

YamlDotNet/Serialization/TypeInspectors/CompositeTypeInspector.cs

@@ -28,7 +28,7 @@ namespace YamlDotNet.Serialization.TypeInspectors
     /// <summary>
     /// Aggregates the results from multiple <see cref="ITypeInspector" /> into a single one.
     /// </summary>
-    public sealed class CompositeTypeInspector : TypeInspectorSkeleton
+    public class CompositeTypeInspector : TypeInspectorSkeleton
     {
         private readonly IEnumerable<ITypeInspector> typeInspectors;
 

YamlDotNet/Serialization/TypeInspectors/NamingConventionTypeInspector.cs

@@ -29,7 +29,7 @@ namespace YamlDotNet.Serialization.TypeInspectors
     /// Wraps another <see cref="ITypeInspector"/> and applies a
     /// naming convention to the names of the properties.
     /// </summary>
-    public sealed class NamingConventionTypeInspector : TypeInspectorSkeleton
+    public class NamingConventionTypeInspector : TypeInspectorSkeleton
     {
         private readonly ITypeInspector innerTypeDescriptor;
         private readonly INamingConvention namingConvention;

YamlDotNet/Serialization/TypeInspectors/ReadableAndWritablePropertiesTypeInspector.cs

@@ -28,7 +28,7 @@ namespace YamlDotNet.Serialization.TypeInspectors
     /// <summary>
     /// Returns the properties of a type that are both readable and writable.
     /// </summary>
-    public sealed class ReadableAndWritablePropertiesTypeInspector : TypeInspectorSkeleton
+    public class ReadableAndWritablePropertiesTypeInspector : TypeInspectorSkeleton
     {
         private readonly ITypeInspector innerTypeDescriptor;
 

YamlDotNet/Serialization/TypeInspectors/ReadableFieldsTypeInspector.cs

@@ -30,7 +30,7 @@ namespace YamlDotNet.Serialization.TypeInspectors
     /// <summary>
     /// Returns the properties and fields of a type that are readable.
     /// </summary>
-    public sealed class ReadableFieldsTypeInspector : ReflectionTypeInspector
+    public class ReadableFieldsTypeInspector : ReflectionTypeInspector
     {
         private readonly ITypeResolver typeResolver;
 
@@ -46,7 +46,7 @@ public override IEnumerable<IPropertyDescriptor> GetProperties(Type type, object
                 .Select(p => (IPropertyDescriptor)new ReflectionFieldDescriptor(p, typeResolver));
         }
 
-        private sealed class ReflectionFieldDescriptor : IPropertyDescriptor
+        protected class ReflectionFieldDescriptor : IPropertyDescriptor
         {
             private readonly FieldInfo fieldInfo;
             private readonly ITypeResolver typeResolver;

YamlDotNet/Serialization/TypeInspectors/ReadablePropertiesTypeInspector.cs

@@ -30,7 +30,7 @@ namespace YamlDotNet.Serialization.TypeInspectors
     /// <summary>
     /// Returns the properties of a type that are readable.
     /// </summary>
-    public sealed class ReadablePropertiesTypeInspector : ReflectionTypeInspector
+    public class ReadablePropertiesTypeInspector : ReflectionTypeInspector
     {
         private readonly ITypeResolver typeResolver;
         private readonly bool includeNonPublicProperties;
@@ -60,7 +60,7 @@ public override IEnumerable<IPropertyDescriptor> GetProperties(Type type, object
                 .Select(p => (IPropertyDescriptor)new ReflectionPropertyDescriptor(p, typeResolver));
         }
 
-        private sealed class ReflectionPropertyDescriptor : IPropertyDescriptor
+        protected class ReflectionPropertyDescriptor : IPropertyDescriptor
         {
             private readonly PropertyInfo propertyInfo;
             private readonly ITypeResolver typeResolver;

YamlDotNet/Serialization/TypeInspectors/ReflectionTypeInspector.cs

@@ -59,7 +59,7 @@ public override string GetEnumValue(object enumValue)
             if (enumMembers.Length > 0)
             {
                 var attribute = enumMembers[0].GetCustomAttribute<EnumMemberAttribute>();
-                if (!string.IsNullOrWhiteSpace(attribute?.Value))
+                if (attribute?.Value != null)
                 {
                     result = attribute.Value;
                 }

YamlDotNet/Serialization/TypeInspectors/WritablePropertiesTypeInspector.cs

@@ -30,7 +30,7 @@ namespace YamlDotNet.Serialization.TypeInspectors
     /// <summary>
     /// Returns the properties of a type that are writable.
     /// </summary>
-    public sealed class WritablePropertiesTypeInspector : ReflectionTypeInspector
+    public class WritablePropertiesTypeInspector : ReflectionTypeInspector
     {
         private readonly ITypeResolver typeResolver;
         private readonly bool includeNonPublicProperties;
@@ -61,7 +61,7 @@ public override IEnumerable<IPropertyDescriptor> GetProperties(Type type, object
                 .ToArray();
         }
 
-        private sealed class ReflectionPropertyDescriptor : IPropertyDescriptor
+        protected class ReflectionPropertyDescriptor : IPropertyDescriptor
         {
             private readonly PropertyInfo propertyInfo;
             private readonly ITypeResolver typeResolver;