fix: add ArgumentNullException guards to BaseReflectionConverter entry points

Replace cryptic NullReferenceExceptions with explicit ArgumentNullException
throwing the parameter name. Guards added to TryModify, TryModifyField,
TryModifyProperty, Serialize, SerializeFields, SerializeProperties,
Deserialize, TryDeserializeValue, TryDeserializeValueInternal,
DeserializeValueAsJsonElement, CreateInstance, and GetDefaultValue.

Author: IvanMurzak

ReflectorNet/src/Converter/Reflection/Base/BaseReflectionConverter.DefaultValue.cs

@@ -43,8 +43,8 @@ public abstract partial class BaseReflectionConverter<T> : IReflectionConverter
         /// <exception cref="ArgumentException">Thrown when type cannot be instantiated due to constructor limitations.</exception>
         public virtual object? CreateInstance(Reflector reflector, Type type)
         {
-            if (type == null)
-                throw new ArgumentNullException(nameof(type));
+            if (reflector == null) throw new ArgumentNullException(nameof(reflector));
+            if (type == null) throw new ArgumentNullException(nameof(type));
 
             // Handle enums
             if (type.IsEnum)
@@ -155,6 +155,9 @@ public abstract partial class BaseReflectionConverter<T> : IReflectionConverter
         /// <returns>An appropriate default value for the specified type.</returns>
         public virtual object? GetDefaultValue(Reflector reflector, Type type)
         {
+            if (reflector == null) throw new ArgumentNullException(nameof(reflector));
+            if (type == null) throw new ArgumentNullException(nameof(type));
+
             // Handle nullable types first
             if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>))
                 return null;

ReflectorNet/src/Converter/Reflection/Base/BaseReflectionConverter.Deserialize.cs

@@ -59,6 +59,9 @@ public abstract partial class BaseReflectionConverter<T> : IReflectionConverter
             ILogger? logger = null,
             DeserializationContext? context = null)
         {
+            if (reflector == null) throw new ArgumentNullException(nameof(reflector));
+            if (data == null) throw new ArgumentNullException(nameof(data));
+
             if (!TryDeserializeValue(
                 reflector,
                 data: data,
@@ -216,6 +219,8 @@ protected virtual bool TryDeserializeValue(
             Logs? logs = null,
             ILogger? logger = null)
         {
+            if (reflector == null) throw new ArgumentNullException(nameof(reflector));
+
             if (data == null)
             {
                 result = null;
@@ -270,6 +275,10 @@ protected virtual bool TryDeserializeValueInternal(
             Logs? logs = null,
             ILogger? logger = null)
         {
+            if (reflector == null) throw new ArgumentNullException(nameof(reflector));
+            if (data == null) throw new ArgumentNullException(nameof(data));
+            if (type == null) throw new ArgumentNullException(nameof(type));
+
             var padding = StringUtils.GetPadding(depth);
 
             if (AllowCascadeSerialization)
@@ -361,6 +370,10 @@ protected virtual bool TryDeserializeValueInternal(
             Logs? logs = null,
             ILogger? logger = null)
         {
+            if (reflector == null) throw new ArgumentNullException(nameof(reflector));
+            if (data == null) throw new ArgumentNullException(nameof(data));
+            if (type == null) throw new ArgumentNullException(nameof(type));
+
             return reflector.JsonSerializer.Deserialize(
                 reflector,
                 data.valueJsonElement,

ReflectorNet/src/Converter/Reflection/Base/BaseReflectionConverter.Modify.cs

@@ -57,6 +57,10 @@ public virtual bool TryModify(
             BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance,
             ILogger? logger = null)
         {
+            if (reflector == null) throw new ArgumentNullException(nameof(reflector));
+            if (data == null) throw new ArgumentNullException(nameof(data));
+            if (type == null) throw new ArgumentNullException(nameof(type));
+
             var padding = StringUtils.GetPadding(depth);
 
             if (obj == null)
@@ -256,6 +260,11 @@ protected virtual bool TryModifyField(
             BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance,
             ILogger? logger = null)
         {
+            if (reflector == null) throw new ArgumentNullException(nameof(reflector));
+            if (obj == null) throw new ArgumentNullException(nameof(obj));
+            if (objType == null) throw new ArgumentNullException(nameof(objType));
+            if (fieldValue == null) throw new ArgumentNullException(nameof(fieldValue));
+
             var padding = StringUtils.GetPadding(depth);
 
             if (string.IsNullOrEmpty(fieldValue.name))
@@ -371,6 +380,11 @@ protected virtual bool TryModifyProperty(
             BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance,
             ILogger? logger = null)
         {
+            if (reflector == null) throw new ArgumentNullException(nameof(reflector));
+            if (obj == null) throw new ArgumentNullException(nameof(obj));
+            if (objType == null) throw new ArgumentNullException(nameof(objType));
+            if (propertyValue == null) throw new ArgumentNullException(nameof(propertyValue));
+
             var padding = StringUtils.GetPadding(depth);
 
             if (string.IsNullOrEmpty(propertyValue.name))

ReflectorNet/src/Converter/Reflection/Base/BaseReflectionConverter.Serialize.cs

@@ -32,6 +32,8 @@ public virtual SerializedMember Serialize(
             ILogger? logger = null,
             SerializationContext? context = null)
         {
+            if (reflector == null) throw new ArgumentNullException(nameof(reflector));
+
             var actualType = fallbackType ?? obj?.GetType() ?? typeof(T);
 
             return InternalSerialize(
@@ -56,6 +58,9 @@ public virtual SerializedMember Serialize(
             ILogger? logger = null,
             SerializationContext? context = null)
         {
+            if (reflector == null) throw new ArgumentNullException(nameof(reflector));
+            if (obj == null) throw new ArgumentNullException(nameof(obj));
+
             var serializedFields = default(SerializedMemberList);
             var objType = obj.GetType();
 
@@ -116,6 +121,9 @@ public virtual SerializedMember Serialize(
             ILogger? logger = null,
             SerializationContext? context = null)
         {
+            if (reflector == null) throw new ArgumentNullException(nameof(reflector));
+            if (obj == null) throw new ArgumentNullException(nameof(obj));
+
             var serializedProperties = default(SerializedMemberList);
             var objType = obj.GetType();