Make assignments on BaseAddon class objects work as expected

The descriptors were being silently clobbered for a while now, and
I never noticed. Oops!

hippolyzer/lib/proxy/addon_utils.py

@@ -143,7 +143,34 @@ def ais_folder_to_inventory_data(ais_folder: dict):
     )
 
 
-class BaseAddon(abc.ABC):
+class MetaBaseAddon(abc.ABCMeta):
+    """
+    Metaclass for BaseAddon that prevents class member assignments from clobbering descriptors
+
+    Without this things like:
+
+        class Foo(BaseAddon):
+            bar: int = GlobalProperty(0)
+
+        Foo.bar = 2
+
+    Won't work as you expect!
+    """
+    def __setattr__(self, key: str, value):
+        # TODO: Keep track of AddonProperties in __new__ or something?
+        try:
+            existing = object.__getattribute__(self, key)
+        except AttributeError:
+            # If the attribute doesn't exist then it's fine to use the base setattr.
+            super().__setattr__(key, value)
+            return
+        if existing and isinstance(existing, BaseAddonProperty):
+            existing.__set__(self, value)
+            return
+        super().__setattr__(key, value)
+
+
+class BaseAddon(metaclass=MetaBaseAddon):
     def _schedule_task(self, coro: Coroutine, session=None,
                        region_scoped=False, session_scoped=True, addon_scoped=True):
         session = session or addon_ctx.session.get(None) or None

tests/proxy/integration/test_addons.py

@@ -33,10 +33,11 @@ class MockAddon(BaseAddon):
 
 
 PARENT_ADDON_SOURCE = """
-from hippolyzer.lib.proxy.addon_utils import BaseAddon
+from hippolyzer.lib.proxy.addon_utils import BaseAddon, GlobalProperty
 
 class ParentAddon(BaseAddon):
     baz = None
+    quux: int = GlobalProperty(0)
 
     @classmethod
     def foo(cls):
@@ -136,3 +137,16 @@ class AddonIntegrationTests(BaseProxyTest):
         AddonManager.unload_addon_from_path(str(self.parent_path), reload=True)
         await asyncio.sleep(0.001)
         self.assertNotIn('hippolyzer.user_addon_parent_addon', sys.modules)
+
+    async def test_global_property_access_and_set(self):
+        with open(self.parent_path, "w") as f:
+            f.write(PARENT_ADDON_SOURCE)
+        AddonManager.load_addon_from_path(str(self.parent_path), reload=True)
+        # Wait for the init hooks to run
+        await asyncio.sleep(0.001)
+        self.assertFalse("quux" in self.session_manager.addon_ctx)
+        parent_addon_mod = AddonManager.FRESH_ADDON_MODULES['hippolyzer.user_addon_parent_addon']
+        self.assertEqual(0, parent_addon_mod.ParentAddon.quux)
+        self.assertEqual(0, self.session_manager.addon_ctx["quux"])
+        parent_addon_mod.ParentAddon.quux = 1
+        self.assertEqual(1, self.session_manager.addon_ctx["quux"])