simpler way to check if enum property is valid

Well, it's simpler to use but not really simpler in implementation 😅
Thanks to @Gorgious56 for helping out
Hopefully, it's a farewell to those annoying warnings

see https://blenderartists.org/t/best-way-to-handle-dynamic-enum-items-without-pyrna-enum-to-py-current-value-matches-no-enum

src/blenderbim/blenderbim/bim/module/model/data.py

@@ -121,9 +121,10 @@ class AuthoringData:
     def type_thumbnail(cls):
         if not cls.data["relating_type_id"]:
             return 0
-        if not tool.Blender.enum_property_has_valid_index(cls.props, "relating_type_id", cls.data["relating_type_id"]):
+        relating_type_id = tool.Blender.get_enum_safe(cls.props, "relating_type_id")
+        if relating_type_id is None:
             return 0
-        element = tool.Ifc.get().by_id(int(cls.props.relating_type_id))
+        element = tool.Ifc.get().by_id(int(relating_type_id))
         return cls.type_thumbnails.get(element.id(), None) or 0
 
     @classmethod
@@ -251,10 +252,8 @@ class AuthoringData:
 
     @classmethod
     def predefined_type(cls):
-        if not tool.Blender.enum_property_has_valid_index(cls.props, "relating_type_id", cls.data["relating_type_id"]):
-            return
-        relating_type_id = cls.props.relating_type_id
-        if not relating_type_id:
+        relating_type_id = tool.Blender.get_enum_safe(cls.props, "relating_type_id")
+        if relating_type_id is None:
             return
         relating_type = tool.Ifc.get().by_id(int(relating_type_id))
         if not hasattr(relating_type, "PredefinedType"):

src/blenderbim/blenderbim/bim/module/model/prop.py

@@ -60,7 +60,7 @@ def update_ifc_class(self, context):
     bpy.ops.bim.load_type_thumbnails(ifc_class=self.ifc_class)
     AuthoringData.data["relating_type_id"] = AuthoringData.relating_type_id()
     AuthoringData.data["type_thumbnail"] = AuthoringData.type_thumbnail()
-    if not tool.Blender.enum_property_has_valid_index(self, "relating_type_id", AuthoringData.data["relating_type_id"]):
+    if tool.Blender.get_enum_safe(self, "relating_type_id") is None:
         self["relating_type_id"] = 0
 
 

src/blenderbim/blenderbim/tool/blender.py

@@ -468,20 +468,41 @@ class Blender(blenderbim.core.tool.Blender):
             active_object.select_set(True)
 
     @classmethod
-    def enum_property_has_valid_index(cls, props: bpy.types.PropertyGroup, prop_name: str, enum_items: tuple) -> bool:
+    def get_enum_safe(cls, props: bpy.types.PropertyGroup, prop_name: str) -> Union[str, None]:
         """method created for readibility and to avoid console warnings like
         `pyrna_enum_to_py: current value '17' matches no enum in 'BIMModelProperties', '', 'relating_type_id'`
         """
-        items_amount = len(enum_items)
+        # Yes, accessing items through annotations is a bit hacky
+        # but it's the only way to get the dynamic enum items
+        # besides providing them to get_enum_safe explicitly.
+        prop_keywords = props.__annotations__[prop_name].keywords
+        items = prop_keywords.get("items")
+        if items is None:
+            return None
+        if not isinstance(items, (list, tuple)):
+            # items are retrieved through a callback, not a static list / tuple :
+            items = items(props, bpy.context)
+
+        items_amount = len(items)
         # If enum has no items it seems to always produce a warning.
         # E.g. if you try to get it's value directly: `BIMModelProperties.relating_type_id`.
         if items_amount == 0:
-            return False
-        current_value_index = props.get(prop_name, None)
-        # assuming the default value is fine
-        if current_value_index is None:
-            return True
-        return current_value_index < items_amount
+            return None
+
+        index = props.get(prop_name)
+        # If value was never changed (still default), we can just retrieve it from the enum.
+        if index is None:
+            default_value = prop_keywords.get("default")
+            if isinstance(default_value, int):
+                index = default_value
+            else:
+                # If default value is a string then it's a static enum
+                # and we can just return it.
+                return default_value
+        # Ensure index is valid.
+        if items_amount > index >= 0:
+            return items[index][0]
+        return None
 
     @classmethod
     def append_data_block(cls, filepath: str, data_block_type: str, name: str, link=False, relative=False) -> dict: