Improve Python frame asserts message

Author: steve-s

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/function/PArguments.java

@@ -65,6 +65,14 @@ public final class PArguments {
     private static final int INDEX_CURRENT_EXCEPTION = 5;
     public static final int USER_ARGUMENTS_OFFSET = 6;
 
+    public static boolean assertIsPythonFrame(Frame frame) {
+        assert frame != null;
+        Object[] frameArgs = frame.getArguments();
+        assert frameArgs.length >= USER_ARGUMENTS_OFFSET : frameArgs.length;
+        assert frameArgs[INDEX_CURRENT_FRAME_INFO] instanceof PFrame.Reference : frameArgs[INDEX_CURRENT_FRAME_INFO];
+        return true;
+    }
+
     public static boolean isPythonFrame(Frame frame) {
         return frame != null && isPythonFrame(frame.getArguments());
     }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/frame/ReadFrameNode.java

@@ -440,7 +440,7 @@ public StackWalkResult visitFrame(FrameInstance frameInstance) {
                     if (!selector.skip(pRootNode)) {
                         if (i == level) {
                             Frame frame = ReadFrameNode.getFrame(frameInstance, frameAccess);
-                            assert PArguments.isPythonFrame(frame);
+                            assert PArguments.assertIsPythonFrame(frame);
                             IndirectCallData.setCallerFlagsOnIndirectCallData(callNode, callerFlags);
                             if (prevRootNode instanceof PRootNode prevPRootNode && prevPRootNode.setsUpCalleeContext()) {
                                 // Update the flags in the callee

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/ExecutionContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0
@@ -181,7 +181,7 @@ protected static void prepareCall(VirtualFrame frame, Object[] callArguments, in
                         @Bind Node inliningTarget,
                         @Cached PassCallerFrameNode passCallerFrame,
                         @Cached PassExceptionStateNode passExceptionState) {
-            assert PArguments.isPythonFrame(frame) || inliningTarget.getRootNode() instanceof TopLevelExceptionHandler : "calling from non-Python or non-top-level frame";
+            assert inliningTarget.getRootNode() instanceof TopLevelExceptionHandler || PArguments.assertIsPythonFrame(frame) : "calling from non-Python or non-top-level frame";
             passCallerFrame.execute(frame, inliningTarget, callArguments, callerFlags);
             passExceptionState.execute(frame, inliningTarget, callArguments, CallerFlags.needsExceptionState(callerFlags));
         }