Index: Objects/unicodeobject.c
===================================================================
--- Objects/unicodeobject.c	(révision 88500)
+++ Objects/unicodeobject.c	(copie de travail)
@@ -1460,9 +1460,12 @@
     PyObject *buffer = NULL, *unicode;
     Py_buffer info;
     char lower[11];  /* Enough for any encoding shortcut */
+    static const char *empty = "";
 
     if (encoding == NULL)
         encoding = PyUnicode_GetDefaultEncoding();
+    if (s == NULL)
+        s = empty;
 
     /* Shortcuts for common default encodings */
     if (normalize_encoding(encoding, lower, sizeof(lower))) {
Index: Objects/memoryobject.c
===================================================================
--- Objects/memoryobject.c	(révision 88500)
+++ Objects/memoryobject.c	(copie de travail)
@@ -75,6 +75,11 @@
 {
     PyMemoryViewObject *mview;
 
+    if (info->buf == NULL) {
+        PyErr_SetString(PyExc_ValueError,
+            "cannot make memory view from a buffer with a NULL data pointer");
+        return NULL;
+    }
     mview = (PyMemoryViewObject *)
         PyObject_GC_New(PyMemoryViewObject, &PyMemoryView_Type);
     if (mview == NULL)
Index: Lib/test/test_capi.py
===================================================================
--- Lib/test/test_capi.py	(révision 88500)
+++ Lib/test/test_capi.py	(copie de travail)
@@ -50,7 +50,18 @@
                          b'Fatal Python error:'
                          b' PyThreadState_Get: no current thread')
 
+    def test_memoryview_from_NULL_pointer(self):
+        self.assertRaises(ValueError, _testcapi.make_memoryview_from_NULL_pointer)
 
+    def test_pyunicode_decode_NULL_length_0(self):
+        f = _testcapi.pyunicode_decode_NULL_length_0
+        self.assertEqual(f('ascii'), '')
+        self.assertEqual(f('utf8'), '')
+        self.assertEqual(f('utf-8'), '')
+        self.assertEqual(f('latin1'), '')
+        self.assertEqual(f('latin1', 'replace'), '')
+        self.assertEqual(f('latin-1'), '')
+
 @unittest.skipUnless(threading, 'Threading required for this test.')
 class TestPendingCalls(unittest.TestCase):
 
Index: Modules/_testcapimodule.c
===================================================================
--- Modules/_testcapimodule.c	(révision 88500)
+++ Modules/_testcapimodule.c	(copie de travail)
@@ -2231,6 +2231,15 @@
     return PyErr_NewExceptionWithDoc(name, doc, base, dict);
 }
 
+static PyObject *
+make_memoryview_from_NULL_pointer(PyObject *self)
+{
+    Py_buffer info;
+    if (PyBuffer_FillInfo(&info, NULL, NULL, 1, 1, PyBUF_FULL_RO) < 0)
+        return NULL;
+    return PyMemoryView_FromBuffer(&info);
+}
+
 /* Test that the fatal error from not having a current thread doesn't
    cause an infinite loop.  Run via Lib/test/test_capi.py */
 static PyObject *
@@ -2246,6 +2255,22 @@
     return NULL;
 }
 
+static PyObject *
+pyunicode_decode_NULL_length_0(PyObject *self, PyObject *args, PyObject *kwargs)
+{
+    const char *encoding;
+    const char *errors = "strict";
+
+    static char *kwlist[] = {"encoding", "errors", NULL};
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs,
+        "|ss:pyunicode_decode_NULL_length_0", kwlist,
+        &encoding, &errors))
+        return NULL;
+    return PyUnicode_Decode(NULL, 0, encoding, errors);
+}
+
+
 static PyMethodDef TestMethods[] = {
     {"raise_exception",         raise_exception,                 METH_VARARGS},
     {"raise_memoryerror",   (PyCFunction)raise_memoryerror,  METH_NOARGS},
@@ -2326,7 +2351,11 @@
     {"code_newempty",           code_newempty,                   METH_VARARGS},
     {"make_exception_with_doc", (PyCFunction)make_exception_with_doc,
      METH_VARARGS | METH_KEYWORDS},
+    {"make_memoryview_from_NULL_pointer", (PyCFunction)make_memoryview_from_NULL_pointer,
+     METH_NOARGS},
     {"crash_no_current_thread", (PyCFunction)crash_no_current_thread, METH_NOARGS},
+    {"pyunicode_decode_NULL_length_0", (PyCFunction)pyunicode_decode_NULL_length_0,
+     METH_VARARGS | METH_KEYWORDS},
     {NULL, NULL} /* sentinel */
 };