After Effects: The shortcut property mask of an AVLayer is not of type MaskPropertyGroup.

[RaymondClr]

The mask property, which has the match name ADBE Mask Parade, has a propertyType of PropertyType.INDEXED_GROUP. It is expected to be a PropertyGroup, while its child properties are of the type MaskPropertyGroup.

For example: layer.mask.maskMode provides the correct type hint, but when executing the code, it fails to retrieve any values.

I used a third-party tool to demonstrate this hierarchy issue. This tool can read nested Property hierarchies and display them as JSON:

[zlovatt]

Yes, the current typedefs don't have any way to identify results accessed by matchnames or strings.

You can either check whether it's a MaskPropertyGroup after the fact, or access it from the layer via avLayer.mask (instead of avLayer.property("ADBE Mask Parade") to return the typed MaskPropertyGroup group.