Fix 空指针 (Null pointer) of case 17 paddle.flip (#50028)

* check tensor numel in PyObject_CheckLongOrToLong

* add unittest

paddle/fluid/pybind/op_function_common.cc

@@ -30,6 +30,7 @@
 #include "paddle/fluid/imperative/tracer.h"
 #include "paddle/fluid/imperative/type_defs.h"
 #include "paddle/fluid/operators/ops_extra_info.h"
+#include "paddle/fluid/pybind/eager.h"
 #include "paddle/fluid/pybind/imperative.h"
 #include "paddle/phi/common/complex.h"
 
@@ -70,7 +71,8 @@ bool PyObject_CheckLongOrToLong(PyObject** obj) {
   if ((PyLong_Check(*obj) && !PyBool_Check(*obj)) ||
       PyObject_IsInstance(*obj, (PyObject*)g_vartype_pytype) ||  // NOLINT
       PyObject_IsInstance(*obj, (PyObject*)g_varbase_pytype) ||  // NOLINT
-      PyObject_IsInstance(*obj, (PyObject*)p_tensor_type)) {     // NOLINT
+      (PyObject_IsInstance(*obj, (PyObject*)p_tensor_type) &&    // NOLINT
+       (((TensorObject*)(*obj))->tensor.numel() == 1))) {        // NOLINT
     return true;
   }
 

python/paddle/fluid/tests/unittests/test_flip.py

@@ -196,6 +196,23 @@ class TestFlipTripleGradCheck(unittest.TestCase):
             self.func(p)
 
 
+class TestFlipError(unittest.TestCase):
+    def test_axis(self):
+        paddle.enable_static()
+
+        def test_axis_rank():
+            input = fluid.data(name='input', dtype='float32', shape=[2, 3])
+            output = paddle.flip(input, axis=[[0]])
+
+        self.assertRaises(TypeError, test_axis_rank)
+
+        def test_axis_rank2():
+            input = fluid.data(name='input', dtype='float32', shape=[2, 3])
+            output = paddle.flip(input, axis=[[0, 0], [1, 1]])
+
+        self.assertRaises(TypeError, test_axis_rank2)
+
+
 if __name__ == "__main__":
     paddle.enable_static()
     unittest.main()