bpo-20627: Fix error message when keyword arguments are used (#2115)

1 files changed, 14 insertions, 6 deletions

diff --git a/Modules/_struct.c b/Modules/_struct.c
index 5b74ec5b49..46e7b4071b 100644
--- a/Modules/_struct.c
+++ b/Modules/_struct.c
@@ -1823,6 +1823,9 @@ s_pack(PyObject *self, PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
     PyObject *result;
 
     /* Validate arguments. */
+    if (!_PyArg_NoStackKeywords("pack", kwnames)) {
+        return NULL;
+    }
     soself = (PyStructObject *)self;
     assert(PyStruct_Check(self));
     assert(soself->s_codes != NULL);
@@ -1832,9 +1835,6 @@ s_pack(PyObject *self, PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
             "pack expected %zd items for packing (got %zd)", soself->s_len, nargs);
         return NULL;
     }
-    if (!_PyArg_NoStackKeywords("pack", kwnames)) {
-        return NULL;
-    }
 
     /* Allocate a new buffer */
     result = PyBytes_FromStringAndSize((char *)NULL, soself->s_size);
@@ -1866,6 +1866,9 @@ s_pack_into(PyObject *self, PyObject **args, Py_ssize_t nargs, PyObject *kwnames
     Py_ssize_t offset;
 
     /* Validate arguments.  +1 is for the first arg as buffer. */
+    if (!_PyArg_NoStackKeywords("pack_into", kwnames)) {
+        return NULL;
+    }
     soself = (PyStructObject *)self;
     assert(PyStruct_Check(self));
     assert(soself->s_codes != NULL);
@@ -1886,9 +1889,6 @@ s_pack_into(PyObject *self, PyObject **args, Py_ssize_t nargs, PyObject *kwnames
         }
         return NULL;
     }
-    if (!_PyArg_NoStackKeywords("pack_into", kwnames)) {
-        return NULL;
-    }
 
     /* Extract a writable memory buffer from the first argument */
     if (!PyArg_Parse(args[0], "w*", &buffer))
@@ -2131,6 +2131,10 @@ pack(PyObject *self, PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
     PyObject *s_object = NULL;
     PyObject *format, *result;
 
+    if (!_PyArg_NoStackKeywords("pack", kwnames)) {
+        return NULL;
+    }
+
     if (nargs == 0) {
         PyErr_SetString(PyExc_TypeError, "missing format argument");
         return NULL;
@@ -2159,6 +2163,10 @@ pack_into(PyObject *self, PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
     PyObject *s_object = NULL;
     PyObject *format, *result;
 
+    if (!_PyArg_NoStackKeywords("pack_into", kwnames)) {
+        return NULL;
+    }
+
     if (nargs == 0) {
         PyErr_SetString(PyExc_TypeError, "missing format argument");
         return NULL;