[Solved] Problem register module with submodules

Coding Python Support
1

I’m developing an addon, which is really two addons combined into one. The addon is a package with the following structure:

foo:
    bar
    baz
    shared

The packages bar and baz are defining a lot of classes, whereas shared contains code that used by both the other packages. The reason why I don’t want to make two separate addons is that the shared code is quite large, and I don’t want to duplicate the code. My problem is that when I try to register the submodules, I get the error message:

Exception: register_module(‘foo.bar’): defines no classes

init.py in foo:

bl_info = {...}
    
def register:
    bar.register()
    baz.register()
       
def unregister:
    bar.unregister()
    baz.unregister()
if __name__ == "__main__":
    register()

init.py in bar:

Define classes...
def register():
    bpy.utils.register_module(__name__)
def unregister():
    bpy.utils.unregister_module(__name__)

It works to register the classes explicitly with bpy.utils.register_class, but this becomes messy to maintain.
A workaround would be to make two separate addons, include the shared package into the bar addon, and let baz import from bar. However, this creates an inter-addon dependence which could lead to confusion.

2

you can’t register scripts which do not contain any classes deriving from bpy.types (simply don’t, it’s not necessary)

3

The top module does not define any classes, but foo.bar and foo.baz do. Anyway, I found the solution: remove registration from the submodules and call register_module(name) in the top module instead.