fix(xmlupload): provide a helpful error message if default-ontology in XML file doesn't exist (DEV-2577)

src/dsp_tools/utils/xml_upload.py

@@ -369,6 +369,33 @@ def parse_xml_file(input_file: Union[str, Path, etree._ElementTree[Any]]) -> etr
     return tree.getroot()
 
 
+def _check_if_onto_name_exists(
+    resclass_name_2_type: dict[str, type],
+    ontoname: str,
+    shortcode: str,
+) -> None:
+    """
+    Check if the "default-ontology" of the <knora> tag of the XML file exists on the DSP server.
+
+    Args:
+        resclass_name_2_type: infos about the resource classes that exist on the DSP server for the current ontology
+        ontoname: name of the ontology as referenced in the XML file
+        shortcode: shortcode of the project as referenced in the XML file
+
+    Raises:
+        UserError: if the ontology does not exist on the DSP server
+    """
+    existing_onto_names = {x.split(":")[0] for x in resclass_name_2_type}
+    existing_onto_names.remove("knora-api")
+    if ontoname not in existing_onto_names:
+        err_msg = (
+            f"ERROR: The <knora> tag of your XML file references the default-ontology '{ontoname}', "
+            f"but the project {shortcode} on the DSP server contains only the ontologies {existing_onto_names}"
+        )
+        logger.error(err_msg)
+        raise UserError(err_msg)
+
+
 def _check_consistency_with_ontology(
     resources: list[XMLResource],
     resclass_name_2_type: dict[str, type],
@@ -401,6 +428,11 @@ def _check_consistency_with_ontology(
         )
         logger.error(err_msg)
         raise UserError(err_msg)
+    _check_if_onto_name_exists(
+        resclass_name_2_type=resclass_name_2_type,
+        ontoname=ontoname,
+        shortcode=shortcode,
+    )
     knora_properties = resclass_name_2_type[resources[0].restype].knora_properties  # type: ignore[attr-defined]
 
     for resource in resources: