add back GetOption methods, but mark them as obsolete

csharp/src/Google.Protobuf/Reflection/EnumDescriptor.cs

@@ -137,5 +137,24 @@ namespace Google.Protobuf.Reflection
         /// NOTE: A defensive copy is created each time this property is retrieved.
         /// </summary>
         public EnumOptions Options => (Proto.Options as IDeepCloneable<EnumOptions>)?.Clone();
+
+        /// <summary>
+        /// Gets a single value enum option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public T GetOption<T>(Extension<EnumOptions, T> extension)
+        {
+            var value = Proto.Options.GetExtension(extension);
+            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
+        }
+
+        /// <summary>
+        /// Gets a repeated value enum option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public RepeatedField<T> GetOption<T>(RepeatedExtension<EnumOptions, T> extension)
+        {
+            return Proto.Options.GetExtension(extension).Clone();
+        }
     }
 }

csharp/src/Google.Protobuf/Reflection/EnumValueDescriptor.cs

@@ -82,6 +82,25 @@ namespace Google.Protobuf.Reflection
         /// NOTE: A defensive copy is created each time this property is retrieved.
         /// </summary>
         public EnumValueOptions Options => (Proto.Options as IDeepCloneable<EnumValueOptions>)?.Clone();
+
+        /// <summary>
+        /// Gets a single value enum value option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public T GetOption<T>(Extension<EnumValueOptions, T> extension)
+        {
+            var value = Proto.Options.GetExtension(extension);
+            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
+        }
+
+        /// <summary>
+        /// Gets a repeated value enum value option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public RepeatedField<T> GetOption<T>(RepeatedExtension<EnumValueOptions, T> extension)
+        {
+            return Proto.Options.GetExtension(extension).Clone();
+        }
     }
 }
  

csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs

@@ -314,6 +314,25 @@ namespace Google.Protobuf.Reflection
         /// </summary>
         public FieldOptions Options => (Proto.Options as IDeepCloneable<FieldOptions>)?.Clone();
 
+        /// <summary>
+        /// Gets a single value field option for this descriptor
+        /// </summary>
+         [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public T GetOption<T>(Extension<FieldOptions, T> extension)
+        {
+            var value = Proto.Options.GetExtension(extension);
+            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
+        }
+
+        /// <summary>
+        /// Gets a repeated value field option for this descriptor
+        /// </summary>
+         [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public RepeatedField<T> GetOption<T>(RepeatedExtension<FieldOptions, T> extension)
+        {
+            return Proto.Options.GetExtension(extension).Clone();
+        }
+
         /// <summary>
         /// Look up and cross-link all field types etc.
         /// </summary>

csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs

@@ -557,6 +557,25 @@ namespace Google.Protobuf.Reflection
         /// </summary>
         public FileOptions Options => (Proto.Options as IDeepCloneable<FileOptions>)?.Clone();
 
+        /// <summary>
+        /// Gets a single value file option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public T GetOption<T>(Extension<FileOptions, T> extension)
+        {
+            var value = Proto.Options.GetExtension(extension);
+            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
+        }
+
+        /// <summary>
+        /// Gets a repeated value file option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public RepeatedField<T> GetOption<T>(RepeatedExtension<FileOptions, T> extension)
+        {
+            return Proto.Options.GetExtension(extension).Clone();
+        }
+
         /// <summary>
         /// Performs initialization for the given generic type argument.
         /// </summary>

csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs

@@ -297,6 +297,25 @@ namespace Google.Protobuf.Reflection
         /// </summary>
         public MessageOptions Options => (Proto.Options as IDeepCloneable<MessageOptions>)?.Clone();
 
+        /// <summary>
+        /// Gets a single value message option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public T GetOption<T>(Extension<MessageOptions, T> extension)
+        {
+            var value = Proto.Options.GetExtension(extension);
+            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
+        }
+
+        /// <summary>
+        /// Gets a repeated value message option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public Collections.RepeatedField<T> GetOption<T>(RepeatedExtension<MessageOptions, T> extension)
+        {
+            return Proto.Options.GetExtension(extension).Clone();
+        }
+
         /// <summary>
         /// Looks up and cross-links all fields and nested types.
         /// </summary>

csharp/src/Google.Protobuf/Reflection/MethodDescriptor.cs

@@ -83,6 +83,25 @@ namespace Google.Protobuf.Reflection
         /// </summary>
         public MethodOptions Options => (Proto.Options as IDeepCloneable<MethodOptions>)?.Clone();
 
+        /// <summary>
+        /// Gets a single value method option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public T GetOption<T>(Extension<MethodOptions, T> extension)
+        {
+            var value = Proto.Options.GetExtension(extension);
+            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
+        }
+
+        /// <summary>
+        /// Gets a repeated value method option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public RepeatedField<T> GetOption<T>(RepeatedExtension<MethodOptions, T> extension)
+        {
+            return Proto.Options.GetExtension(extension).Clone();
+        }
+
         internal MethodDescriptor(MethodDescriptorProto proto, FileDescriptor file,
                                   ServiceDescriptor parent, int index)
             : base(file, parent.FullName + "." + proto.Name, index)

csharp/src/Google.Protobuf/Reflection/OneofDescriptor.cs

@@ -127,6 +127,25 @@ namespace Google.Protobuf.Reflection
         /// </summary>
         public OneofOptions Options => (proto.Options as IDeepCloneable<OneofOptions>)?.Clone();
 
+        /// <summary>
+        /// Gets a single value oneof option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public T GetOption<T>(Extension<OneofOptions, T> extension)
+        {
+            var value = proto.Options.GetExtension(extension);
+            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
+        }
+
+        /// <summary>
+        /// Gets a repeated value oneof option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public RepeatedField<T> GetOption<T>(RepeatedExtension<OneofOptions, T> extension)
+        {
+            return proto.Options.GetExtension(extension).Clone();
+        }
+
         internal void CrossLink()
         {
             List<FieldDescriptor> fieldCollection = new List<FieldDescriptor>();

csharp/src/Google.Protobuf/Reflection/ServiceDescriptor.cs

@@ -97,6 +97,25 @@ namespace Google.Protobuf.Reflection
         [Obsolete("CustomOptions are obsolete. Use the Options property.")]
         public CustomOptions CustomOptions => new CustomOptions(Proto.Options?._extensions?.ValuesByNumber);
 
+        /// <summary>
+        /// Gets a single value service option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public T GetOption<T>(Extension<ServiceOptions, T> extension)
+        {
+            var value = Proto.Options.GetExtension(extension);
+            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
+        }
+
+        /// <summary>
+        /// Gets a repeated value service option for this descriptor
+        /// </summary>
+        [Obsolete("GetOption is obsolete. Use the Options property.")]
+        public RepeatedField<T> GetOption<T>(RepeatedExtension<ServiceOptions, T> extension)
+        {
+            return Proto.Options.GetExtension(extension).Clone();
+        }
+
         /// <summary>
         /// The <c>ServiceOptions</c>, defined in <c>descriptor.proto</c>.
         /// Custom options can be retrieved as extensions of the returned message.