BUG: Add missing information in ImpossibleMergeError message

src/caoscrawler/sync_node.py

@@ -87,13 +87,25 @@ class SyncNode(db.Entity):
         self.registered_identifiable = registered_identifiable
 
     def update(self, other: SyncNode) -> None:
-        """update this node with information of given ``other`` SyncNode.
+        """Update this node with information of given ``other`` SyncNode.
+
+        parents are added if they are not yet in the list properties
+        are added in any case. This may lead to duplication of
+        properties. We allow this duplication here and remove it when
+        we create a db.Entity (export_entity function) because if
+        property values are SyncNode objects, they might not be
+        comparable (no ID, no identifiable) yet.
+
+        Raises
+        ------
+        ValueError:
+            The `other` SyncNode doesn't share identifiables with
+            `this` SyncNode, so they can't be merged.
+        ImpossibleMergeError:
+            The two SyncNodes are incompatible in their attributes
+            like "id", "role", "path", "file", "name", or
+            "description".
 
-        parents are added if they are not yet in the list
-        properties are added in any case. This may lead to duplication of properties.
-        We allow this duplication here and remove it when we create a db.Entity (export_entity
-        function) because if property values are SyncNode objects, they might not be comparable (no
-        ID, no identifiable) yet.
         """
 
         if other.identifiable is not None and self.identifiable is not None:
@@ -121,8 +133,9 @@ class SyncNode(db.Entity):
                             f"Trying to update {attr} but this would lead to an "
                             f"override of the value '{self.__getattribute__(attr)}' "
                             f"by the value '{other.__getattribute__(attr)}'",
-                            pname=attr, values=(self.__getattribute__(attr),
-                                                other.__getattribute__(attr))
+                            pname=attr,
+                            value_a=self.__getattribute__(attr),
+                            value_b=other.__getattribute__(attr)
                         )
         for p in other.parents:
             if not parent_in_list(p, self.parents):
@@ -136,6 +149,13 @@ class SyncNode(db.Entity):
         Properties are only added once (based on id or name). If values do not match, an Error is
         raised. If values are SyncNode objects with IDs, they are considered equal if their IDs are
         equal.
+
+        Raises
+        ------
+        RuntimeError:
+            In case of a unsupported role, so no Entity can't be created.
+        ImpossibleMergeError:
+            In case of conflicting property values in this SyncNode.
         """
         ent = None
         if self.role == "Record":
@@ -175,16 +195,10 @@ class SyncNode(db.Entity):
                             unequal = True
 
                 if unequal:
-                    logger.error(
-                        "The Crawler is trying to create an entity,"
-                        " but there are conflicting property values."
-                        f"Problematic Property: {p.name}\n"
-                        f"First value:\n{entval}\n"
-                        f"Second value:\n{pval}\n"
-                        f"{self}"
-                    )
                     ime = ImpossibleMergeError(
-                        "Cannot merge Entities", pname=p.name, values=(entval, pval)
+                        f"The crawler is trying to create an entity \n\n{self}\n\nbut there are "
+                        "conflicting property values.",
+                        pname=p.name, value_a=entval, value_b=pval
                     )
                     raise ime
         return ent