From 0690c79c419b8d2bdfe7c5b6dca57b018f5a5a54 Mon Sep 17 00:00:00 2001
From: Eric Wieser <wieser.eric@gmail.com>
Date: Fri, 7 Jun 2019 01:13:26 -0700
Subject: [PATCH] bpo-37188: Fix a divide-by-zero in arrays of size-0 objects
 (#13881)

---
 Lib/ctypes/test/test_arrays.py | 15 +++++++++++++++
 Modules/_ctypes/_ctypes.c      |  2 +-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/Lib/ctypes/test/test_arrays.py b/Lib/ctypes/test/test_arrays.py
index 87ecbf04e7e..a3e6d76940e 100644
--- a/Lib/ctypes/test/test_arrays.py
+++ b/Lib/ctypes/test/test_arrays.py
@@ -208,6 +208,21 @@ class ArrayTestCase(unittest.TestCase):
             _type_ = c_int
             _length_ = 0
 
+    def test_empty_element_struct(self):
+        class EmptyStruct(Structure):
+            _fields_ = []
+
+        obj = (EmptyStruct * 2)()  # bpo37188: Floating point exception
+        assert sizeof(obj) == 0
+
+    def test_empty_element_array(self):
+        class EmptyArray(Array):
+            _type_ = c_int
+            _length_ = 0
+
+        obj = (EmptyArray * 2)()  # bpo37188: Floating point exception
+        assert sizeof(obj) == 0
+
     def test_bpo36504_signed_int_overflow(self):
         # The overflow check in PyCArrayType_new() could cause signed integer
         # overflow.
diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index f7513a3d74c..2201c4520ad 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -1518,7 +1518,7 @@ PyCArrayType_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
     }
 
     itemsize = itemdict->size;
-    if (length > PY_SSIZE_T_MAX / itemsize) {
+    if (itemsize != 0 && length > PY_SSIZE_T_MAX / itemsize) {
         PyErr_SetString(PyExc_OverflowError,
                         "array too large");
         goto error;