Custom PropertyDrawer targeting interface type doesn't get used

[DarrenRuaneKaizen]

I've got a custom property drawer targeting an interface like the following: [CustomPropertyDrawer(typeof(IEditorClampableVariable), true)]

It works perfectly using the native Unity inspector but PowerInspector doesn't seem to detect it at all. I took a look through the source and made a few observations that may be of some help:

• In CustomEditorUtility.cs in the method GetDrawersByInheritedInspectedTypesFromAttributes there is a check for if (!targetType.IsClass) with a comment saying "value types don't support inheritance". Interface types will return false here. The Type.IsValueType is preferable to check for value types.
• A few lines below, a call is made to targetType.GetExtendingType which will only check the type against known Unity components/scriptable objects if it is a type that derives from UnityEngine.Object (which interfaces will not).
• There's a heavy usage of Type.IsSubclassOf throughout the codebase which will not return true for types that implement interfaces (instead the Type.IsAssignableFrom method could be used).

I understand that there is probably a lot of work involved in making Drawers work when targeting interfaces but my workflow now involves switching back-and-forth between the native inspector and PowerInspector very frequently (when ideally I would like to just stay in PowerInspector!)

[timo-sisus]

Support for Property Drawers and Decorator Drawers targeting interfaces will be added in Update 1.3.4. I also implemented support for targeting interfaces for custom editors - even though this is not even supported in the default inspector - because why not? Unity doesn't seem to complain if you pass an interface parameter to CustomEditorAttribute in any case.

The usage of IsSubclassOf throughout the code bass is intentional, as I always make a clear distinction between getting extending classes of a base class and getting implementing classes of an interface as early as possible for various reasons. I just had not realized that you even could create custom property drawers targeting interfaces.