# HG changeset patch
# Parent  fcf3ae3e7db49dc19279fd5ae39d0aa5fc737f19
Issue #25659: Change assert to TypeError in from_buffer/_copy()

Based on suggestion by Eryk Sun.

diff -r fcf3ae3e7db4 Lib/ctypes/test/test_frombuffer.py
--- a/Lib/ctypes/test/test_frombuffer.py	Mon Nov 14 05:04:36 2016 +0000
+++ b/Lib/ctypes/test/test_frombuffer.py	Sat Nov 19 00:58:04 2016 +0000
@@ -120,5 +120,13 @@
         with self.assertRaises(ValueError):
             (c_int * 1).from_buffer_copy(a, 16 * sizeof(c_int))
 
+    def test_abstract(self):
+        self.assertRaises(TypeError, Array.from_buffer, bytearray(10))
+        self.assertRaises(TypeError, Structure.from_buffer, bytearray(10))
+        self.assertRaises(TypeError, Union.from_buffer, bytearray(10))
+        self.assertRaises(TypeError, Array.from_buffer_copy, b"123")
+        self.assertRaises(TypeError, Structure.from_buffer_copy, b"123")
+        self.assertRaises(TypeError, Union.from_buffer_copy, b"123")
+
 if __name__ == '__main__':
     unittest.main()
diff -r fcf3ae3e7db4 Misc/NEWS
--- a/Misc/NEWS	Mon Nov 14 05:04:36 2016 +0000
+++ b/Misc/NEWS	Sat Nov 19 00:58:04 2016 +0000
@@ -122,6 +122,9 @@
 Library
 -------
 
+- Issue #25659: Prevent crash calling ctypes from_buffer() and
+  from_buffer_copy() methods on abstract classes like Array.
+
 - Issue #19717: Makes Path.resolve() succeed on paths that do not exist.
   Patch by Vajrasky Kok
 
diff -r fcf3ae3e7db4 Modules/_ctypes/_ctypes.c
--- a/Modules/_ctypes/_ctypes.c	Mon Nov 14 05:04:36 2016 +0000
+++ b/Modules/_ctypes/_ctypes.c	Sat Nov 19 00:58:04 2016 +0000
@@ -463,7 +463,10 @@
     Py_ssize_t offset = 0;
 
     StgDictObject *dict = PyType_stgdict(type);
-    assert (dict);
+    if (!dict) {
+        PyErr_SetString(PyExc_TypeError, "abstract class");
+        return NULL;
+    }
 
     if (!PyArg_ParseTuple(args, "O|n:from_buffer", &obj, &offset))
         return NULL;
@@ -531,9 +534,12 @@
     Py_ssize_t offset = 0;
     PyObject *result;
     StgDictObject *dict = PyType_stgdict(type);
-    assert (dict);
-
-    if (!PyArg_ParseTuple(args, "y*|n:from_buffer", &buffer, &offset))
+    if (!dict) {
+        PyErr_SetString(PyExc_TypeError, "abstract class");
+        return NULL;
+    }
+
+    if (!PyArg_ParseTuple(args, "y*|n:from_buffer_copy", &buffer, &offset))
         return NULL;
 
     if (offset < 0) {