Raise SystemError if HPyInit_* does not return a module object

Author: fangerer

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/GraalHPyUniversalModuleBuiltins.java

@@ -120,8 +120,12 @@ private PythonModule loadHPyModule(PythonContext context, String name, String pa
                         HPyCheckHandleResultNode checkHandleResultNode) throws IOException, ApiInitException, ImportException {
             Object result = GraalHPyContext.loadHPyModule(this, context, name, path, debug, checkHandleResultNode);
             if (!(result instanceof PythonModule)) {
-                // TODO: PyModule_FromDefAndSpec((PyModuleDef*)m, spec);
-                throw PRaiseNode.raiseUncached(this, PythonErrorType.NotImplementedError, ErrorMessages.MULTI_PHASE_INIT_OF_EXTENSION_MODULE_S, name);
+                /*
+                 * HPy does currently not support multi-phase extension module initialization. This
+                 * means there is no structure defined in HPy that we could parse. Hence, whenever
+                 * we reach this point, it's an error.
+                 */
+                throw PRaiseNode.raiseUncached(this, PythonErrorType.SystemError, ErrorMessages.INIT_S_RETURNED_AN_UNEXPECTED_VALUE, name);
             }
             PythonModule module = (PythonModule) result;
             module.setAttribute(__FILE__, path);

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/ErrorMessages.java

@@ -812,6 +812,7 @@ public abstract class ErrorMessages {
     public static final String DEQUE_INDEX_OUT_OF_RANGE = "deque index out of range";
     public static final String CAN_ONLY_CONCATENATE_DEQUE_NOT_P_TO_DEQUE = "can only concatenate deque (not \"%p\") to deque";
     public static final String MULTI_PHASE_INIT_OF_EXTENSION_MODULE_S = "multi-phase init of extension module %s";
+    public static final String INIT_S_RETURNED_AN_UNEXPECTED_VALUE = "HPyInit_%s returned an unexpected value (expected a Python module).";
 
     // pickle errors
     public static final String CANNOT_PICKLE_OBJECT_TYPE = "cannot pickle '%p' object";