Index: Python/getargs.c
===================================================================
--- Python/getargs.c	(révision 81910)
+++ Python/getargs.c	(copie de travail)
@@ -935,10 +935,15 @@
         count = convertbuffer(arg, p, &buf);
         if (count < 0)
             return converterr(buf, arg, msgbuf, bufsize);
-        else if (*format == '#') {
+        if (*format == '#') {
             FETCH_SIZE;
             STORE_SIZE(count);
             format++;
+        } else {
+            if (strlen(*p) != count)
+                return converterr(
+                    "string without null bytes or None",
+                    arg, msgbuf, bufsize);
         }
         break;
     }
Index: Lib/test/test_getargs2.py
===================================================================
--- Lib/test/test_getargs2.py	(révision 81910)
+++ Lib/test/test_getargs2.py	(copie de travail)
@@ -293,8 +293,22 @@
         else:
             self.fail('TypeError should have been raised')
 
+class String_TestCase(unittest.TestCase):
+    def test_format_y(self):
+        from _testcapi import getargs_y
+        self.assertEqual(b'bytes', getargs_y(b'bytes'))
+        self.assertRaises(TypeError, getargs_y, b'a\0c')
+        self.assertRaises(TypeError, getargs_y, "unicode")
+        self.assertRaises(TypeError, getargs_y, bytearray(b'abc'))
+        self.assertRaises(TypeError, getargs_y, memoryview(b'abc'))
+
 def test_main():
-    tests = [Signed_TestCase, Unsigned_TestCase, Tuple_TestCase, Keywords_TestCase]
+    tests = [
+        Signed_TestCase,
+        Unsigned_TestCase,
+        Tuple_TestCase,
+        Keywords_TestCase,
+        String_TestCase]
     try:
         from _testcapi import getargs_L, getargs_K
     except ImportError:
Index: Modules/_testcapimodule.c
===================================================================
--- Modules/_testcapimodule.c	(révision 81910)
+++ Modules/_testcapimodule.c	(copie de travail)
@@ -956,6 +956,15 @@
 }
 #endif
 
+static PyObject *
+getargs_y(PyObject *self, PyObject *args)
+{
+    char *str;
+    if (!PyArg_ParseTuple(args, "y", &str))
+        return NULL;
+    return PyBytes_FromString(str);
+}
+
 /* This function not only tests the 'k' getargs code, but also the
    PyLong_AsUnsignedLongMask() and PyLong_AsUnsignedLongMask() functions. */
 static PyObject *
@@ -2055,6 +2064,7 @@
     {"getargs_i",               getargs_i,                       METH_VARARGS},
     {"getargs_l",               getargs_l,                       METH_VARARGS},
     {"getargs_n",               getargs_n,                       METH_VARARGS},
+    {"getargs_y",               getargs_y,                       METH_VARARGS},
 #ifdef HAVE_LONG_LONG
     {"getargs_L",               getargs_L,                       METH_VARARGS},
     {"getargs_K",               getargs_K,                       METH_VARARGS},
@@ -2062,11 +2072,11 @@
     {"test_long_long_and_overflow",
         (PyCFunction)test_long_long_and_overflow, METH_NOARGS},
     {"test_L_code",             (PyCFunction)test_L_code,        METH_NOARGS},
+#endif
     {"codec_incrementalencoder",
      (PyCFunction)codec_incrementalencoder,      METH_VARARGS},
     {"codec_incrementaldecoder",
      (PyCFunction)codec_incrementaldecoder,      METH_VARARGS},
-#endif
     {"test_s_code",             (PyCFunction)test_s_code,        METH_NOARGS},
     {"test_u_code",             (PyCFunction)test_u_code,        METH_NOARGS},
     {"test_Z_code",             (PyCFunction)test_Z_code,        METH_NOARGS},