adapter.xml: verify declared namespaces before deserializing

Previously, if the elements of an XML document are part of an unknown
namespace, this would lead to cryptic error messages such as:

Unexpected top-level list aas:assetAdministrationShells on line 3

where, the correct expected element is indeed
aas:assetAdministrationShells, leaving the user wondering about what
could possibly be wrong. The only difference is the namespace, which
isn't part of the error message, because it gets replaced by the prefix.

To improve the error messages in this case, a check that compares the
namespaces declared on the document against the ones required by the
deserialization, and errors if a required namespace isn't declared.

Partially fix #190

basyx/aas/adapter/xml/xml_deserialization.py

@@ -49,11 +49,13 @@
 import enum
 
 from typing import Any, Callable, Dict, IO, Iterable, Optional, Set, Tuple, Type, TypeVar
-from .xml_serialization import NS_AAS, NS_ABAC, NS_IEC
+from .xml_serialization import NS_MAP, NS_AAS, NS_ABAC, NS_IEC
 from .._generic import MODELING_KIND_INVERSE, ASSET_KIND_INVERSE, KEY_ELEMENTS_INVERSE, KEY_TYPES_INVERSE, \
     IDENTIFIER_TYPES_INVERSE, ENTITY_TYPES_INVERSE, IEC61360_DATA_TYPES_INVERSE, IEC61360_LEVEL_TYPES_INVERSE, \
     KEY_ELEMENTS_CLASSES_INVERSE
 
+REQUIRED_NAMESPACES: Set[str] = {NS_MAP["aas"]}
+
 logger = logging.getLogger(__name__)
 
 T = TypeVar("T")
@@ -1143,13 +1145,22 @@ def _parse_xml_document(file: IO, failsafe: bool = True, **parser_kwargs: Any) -
     parser = etree.XMLParser(remove_blank_text=True, remove_comments=True, **parser_kwargs)
 
     try:
-        return etree.parse(file, parser).getroot()
+        root = etree.parse(file, parser).getroot()
     except etree.XMLSyntaxError as e:
         if failsafe:
             logger.error(e)
             return None
         raise e
 
+    missing_namespaces: Set[str] = REQUIRED_NAMESPACES - set(root.nsmap.values())
+    if missing_namespaces:
+        error_message = f"The following required namespaces are not declared: {' | '.join(missing_namespaces)}" \
+                        + " - Is the input document of an older version?"
+        if not failsafe:
+            raise KeyError(error_message)
+        logger.error(error_message)
+    return root
+
 
 def _select_decoder(failsafe: bool, stripped: bool, decoder: Optional[Type[AASFromXmlDecoder]]) \
         -> Type[AASFromXmlDecoder]: