Add utility method to retrieve dynamic enum items without needing a reference to the callback

This is useful because trying to directly access a dynamic enum with an empty items list throws an error in the console
+ Remove prop search from template_type in pset ui which has only 2 elements

src/blenderbim/blenderbim/bim/helper.py

@@ -108,7 +108,7 @@ def export_attributes(props, callback=None):
     return attributes
 
 
-def prop_with_search(layout, data, prop_name, **kwargs):  
+def prop_with_search(layout, data, prop_name, **kwargs):
     # kwargs are layout.prop arguments (text, icon, etc.)
     row = layout.row(align=True)
     # Magick courtesy of https://blender.stackexchange.com/a/203443/86891
@@ -118,6 +118,20 @@ def prop_with_search(layout, data, prop_name, **kwargs):
     op.prop_name = prop_name
 
 
+def get_enum_items(data, prop_name, context):
+    # Retrieve items from a dynamic EnumProperty, which is otherwise not supported
+    # Or throws an error in the console when the items callback returns an empty list
+    # See https://blender.stackexchange.com/q/215781/86891
+    prop = data.__annotations__[prop_name]
+    items = prop.keywords.get("items")
+    if items is None:
+        return
+    if not isinstance(items, (list, tuple)):
+        # items are retrieved through a callback, not a static list :
+        items = items(data, context)
+    return items
+
+
 class IfcHeaderExtractor:
     def __init__(self, filepath: str):
         self.filepath = filepath

src/blenderbim/blenderbim/bim/module/pset/ui.py

@@ -490,7 +490,7 @@ class BIM_PT_add_edit_custom_properties(Panel):
                 if prop.template_type == "IfcPropertySingleValue":
                     row.prop(prop, prop.get_value_name(), text="")
                 prop_with_search(row, prop, "primary_measure_type", text="")
-                prop_with_search(row, prop, "template_type", text="")
+                row.prop(prop, "template_type", text="")
                 op = row.operator("bim.remove_property_to_edit", icon="X", text="")
                 op.index = index
                 op.option = "AddEditProperties"

src/blenderbim/blenderbim/bim/module/root/operator.py

@@ -31,6 +31,7 @@ import blenderbim.core.root as core
 import blenderbim.tool as tool
 from ifcopenshell.api.void.data import Data as VoidData
 from blenderbim.bim.ifc import IfcStore
+from blenderbim.bim.helper import get_enum_items
 
 
 class Operator:
@@ -131,7 +132,7 @@ class AssignClass(bpy.types.Operator, Operator):
         ifc_class = self.ifc_class or props.ifc_class
         predefined_type = self.userdefined_type if self.predefined_type == "USERDEFINED" else self.predefined_type
         ifc_context = self.context_id
-        if not ifc_context and props.__annotations__["contexts"].keywords.get("items")(props, context):
+        if not ifc_context and get_enum_items(props, "contexts", context):
             ifc_context = int(props.contexts or "0") or None
         if ifc_context:
             ifc_context = tool.Ifc.get().by_id(ifc_context)

src/blenderbim/blenderbim/bim/operator.py

@@ -27,6 +27,7 @@ from . import schema
 from blenderbim.bim.ifc import IfcStore
 from blenderbim.bim.prop import StrProperty
 from blenderbim.bim.ui import IFCFileSelector
+from blenderbim.bim.helper import get_enum_items
 from mathutils import Vector, Matrix, Euler
 from math import radians
 
@@ -545,11 +546,9 @@ class BIM_OT_enum_property_search(bpy.types.Operator):
     def invoke(self, context, event):
         self.clear_collections()
         self.data = context.data
-        items = self.data.__annotations__[self.prop_name].keywords.get("items")
+        items = get_enum_items(self.data, self.prop_name, context)
         if items is None:
             return {"FINISHED"}
-        if not isinstance(items, list):
-            items = items(self.data, context)
         self.add_items_regular(items)
         self.add_items_suggestions()
         return context.window_manager.invoke_props_dialog(self)