Raise verbose System error instead of printing debug information upon Invalid opcode

Also add code to test that path.

Fix python#96711

Author: serge-sans-paille

Lib/test/test_code.py

@@ -337,6 +337,37 @@ def func():
         new_code = code = func.__code__.replace(co_linetable=b'')
         self.assertEqual(list(new_code.co_lines()), [])
 
+    def test_invalid_bytecode(self):
+        def foo(): pass
+        co = foo.__code__
+        CodeType = type(co)
+
+        new_co = CodeType(
+            co.co_argcount,
+            co.co_posonlyargcount,
+            co.co_kwonlyargcount,
+            co.co_nlocals,
+            co.co_stacksize,
+            co.co_flags,
+            b'\xee\x00d\x00S\x00',
+            co.co_consts,
+            co.co_names,
+            co.co_varnames,
+            co.co_filename,
+            co.co_name,
+            co.co_qualname,
+            co.co_firstlineno,
+            co.co_linetable,
+            co.co_exceptiontable,
+            co.co_freevars,
+            co.co_cellvars)
+
+        foo.__code__ = new_co
+        with self.assertRaises(SystemError) as se:
+            foo()
+        self.assertIn("unknown opcode '238'", str(se.exception))
+
+
     @requires_debug_ranges()
     def test_co_positions_artificial_instructions(self):
         import dis

Python/ceval.c

@@ -5051,9 +5051,11 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
             /* Tell C compilers not to hold the opcode variable in the loop.
                next_instr points the current instruction without TARGET(). */
             opcode = _Py_OPCODE(*next_instr);
-            fprintf(stderr, "XXX lineno: %d, opcode: %d\n",
-                    _PyInterpreterFrame_GetLine(frame),  opcode);
-            _PyErr_SetString(tstate, PyExc_SystemError, "unknown opcode");
+            _PyErr_Format(tstate, PyExc_SystemError,
+                          "%U:%d: unknown opcode '%d'",
+                          frame->f_code->co_filename,
+                          _PyInterpreterFrame_GetLine(frame),
+                          opcode);
             goto error;
 
         } /* End instructions */