refactor: implement validating deserializer for YamlDotNet

src/Trash/Config/ConfigurationLoader.cs

@@ -23,6 +23,7 @@ namespace Trash.Config
             _configProvider = configProvider;
             _fileSystem = fileSystem;
             _deserializer = new DeserializerBuilder()
+                .WithRequiredPropertyValidation()
                 .WithNamingConvention(UnderscoredNamingConvention.Instance)
                 // .WithNamingConvention(CamelCaseNamingConvention.Instance)
                 .WithTypeConverter(new YamlNullableEnumTypeConverter())

src/Trash/YamlDotNet/ValidatingDeserializer.cs

@@ -0,0 +1,45 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+using YamlDotNet.Core;
+using YamlDotNet.Serialization;
+
+namespace Trash.YamlDotNet
+{
+    public class ValidatingDeserializer : INodeDeserializer
+    {
+        private readonly INodeDeserializer _nodeDeserializer;
+
+        public ValidatingDeserializer(INodeDeserializer nodeDeserializer)
+        {
+            _nodeDeserializer = nodeDeserializer;
+        }
+
+        public bool Deserialize(IParser parser, Type expectedType,
+            Func<IParser, Type, object?> nestedObjectDeserializer, out object? value)
+        {
+            if (!_nodeDeserializer.Deserialize(parser, expectedType, nestedObjectDeserializer, out value) ||
+                value == null)
+            {
+                return false;
+            }
+
+            var context = new ValidationContext(value, null, null);
+
+            try
+            {
+                Validator.ValidateObject(value, context, true);
+            }
+            catch (ValidationException e)
+            {
+                if (parser.Current == null)
+                {
+                    throw;
+                }
+
+                throw new YamlException(parser.Current.Start, parser.Current.End, e.Message);
+            }
+
+            return true;
+        }
+    }
+}

src/Trash/YamlDotNet/YamlDotNetExtensions.cs

@@ -1,5 +1,6 @@
 using JetBrains.Annotations;
 using YamlDotNet.Serialization;
+using YamlDotNet.Serialization.NodeDeserializers;
 
 namespace Trash.YamlDotNet
 {
@@ -12,6 +13,13 @@ namespace Trash.YamlDotNet
             return extractor.RootObject;
         }
 
+        public static DeserializerBuilder WithRequiredPropertyValidation(this DeserializerBuilder builder)
+        {
+            return builder
+                .WithNodeDeserializer(inner => new ValidatingDeserializer(inner),
+                    s => s.InsteadOf<ObjectNodeDeserializer>());
+        }
+
         [UsedImplicitly(ImplicitUseTargetFlags.Members)]
         private class RootExtractor<T>
             where T : class