Don't segfault if unable to convert non-rectangular inputs to tensor

PiperOrigin-RevId: 216738986

tensorflow/python/eager/tensor_test.py

@@ -347,6 +347,13 @@ class TFETensorUtilTest(test_util.TensorFlowTestCase):
     instance_dir.remove("test_attr")
     self.assertEqual(instance_dir, type_dir)
 
+  def testNonRectangularPackAsConstant(self):
+    l = [array_ops.zeros((10, 1)).numpy(), array_ops.zeros(1).numpy()]
+
+    with self.assertRaisesRegexp(
+        ValueError, "non-rectangular Python sequence"):
+      constant_op.constant(l)
+
 
 if __name__ == "__main__":
   test.main()

tensorflow/python/lib/core/py_seq_tensor.cc

@@ -220,6 +220,7 @@ const char ErrorFoundFloat[] =
       /* Iterate over outer dim, and recursively convert each element. */ \
       const int64 s = shape.dim_size(0);                                  \
       Safe_PyObjectPtr seq = make_safe(PySequence_Fast(obj, ""));         \
+      if (TF_PREDICT_FALSE(seq == nullptr)) return ErrorRectangular;      \
       if (TF_PREDICT_FALSE(s != PySequence_Fast_GET_SIZE(seq.get()))) {   \
         return ErrorRectangular;                                          \
       }                                                                   \