warn in case of multiprop

src/caoscrawler/sync_node.py

@@ -28,6 +28,7 @@ from typing import TYPE_CHECKING, Any, Optional, Union
 import linkahead as db
 import yaml
 from linkahead.common.models import Parent, _ParentList, _Properties
+from warnings import warn
 
 from .exceptions import ImpossibleMergeError
 
@@ -78,6 +79,7 @@ class SyncNode:
         self.description = entity.description
         self.parents = _ParentList().extend(entity.parents)
         self.properties = _Properties().extend(entity.properties)
+        self._check_for_multiproperties()
         # other members
         self.identifiable: Optional[Identifiable] = None
         self.registered_identifiable = registered_identifiable
@@ -216,6 +218,20 @@ class SyncNode:
             + "=====================================================\n"
         )
 
+    def _check_for_multiproperties(self):
+        """ warns if multiproperties are present """
+        ids = set()
+        names = set()
+        for p in self.properties:
+            if p.name is not None:
+                if p.name in names:
+                    warn("Multiproperties are not supported by the crawler.")
+                names.add(p.name)
+            if p.id is not None:
+                if p.id in ids:
+                    warn("Multiproperties are not supported by the crawler.")
+                ids.add(p.id)
+
 
 def parent_in_list(parent: Parent, plist: _ParentList) -> bool:
     """helper function that checks whether a parent with the same name or ID is in the plist"""

unittests/test_sync_node.py

@@ -232,6 +232,12 @@ def test_export_node():
              .add_property(name="a", value='b')
              .add_property(name="a", value='a'))
 
+    # there should be a warning when multiproperties are used
+    with pytest.warns(UserWarning) as caught:
+        SyncNode(rec_a)
+        messages = {str(w.message) for w in caught}
+        assert ("Multiproperties are not supported by the crawler.") in messages
+
     with pytest.raises(ImpossibleMergeError):
         exp = SyncNode(rec_a).export_entity()