MAINT: add more verbose error message

src/caosdb/apiutils.py

@@ -344,7 +344,13 @@ def merge_entities(entity_a: Entity, entity_b: Entity):
                         setattr(entity_a.get_property(key), attribute,
                                 diff_r2["properties"][key][attribute])
                     else:
-                        raise RuntimeError("Merge conflict.")
+                        raise RuntimeError(
+                            f"Merge conflict:\nEntity a ({entity_a.id}, {entity_a.name}) "
+                            f"has a Property '{key}' with {attribute}="
+                            f"{diff_r2['properties'][key][attribute]}\n"
+                            f"Entity b ({entity_b.id}, {entity_b.name}) "
+                            f"has a Property '{key}' with {attribute}="
+                            f"{diff_r1['properties'][key][attribute]}")
         else:
             # TODO: This is a temporary FIX for
             #       https://gitlab.indiscale.com/caosdb/src/caosdb-pylib/-/issues/105