Add a check on namespace feature when enabling namespace prefixes

Author: ukarroum

Lib/xml/sax/expatreader.py

@@ -156,6 +156,8 @@ def setFeature(self, name, state):
                 raise SAXNotSupportedException(
                     "expat does not read external parameter entities")
         elif name == feature_namespace_prefixes:
+            if state and not self._namespaces:
+                raise SAXException(f"{feature_namespace_prefixes} requires {feature_namespaces} to be enabled")
             self._namespace_prefixes = state
         else:
             raise SAXNotRecognizedException(