From 448801da96c70699e2ca0798efdfe86d45f37f06 Mon Sep 17 00:00:00 2001
From: Dennis Sweeney <36520290+sweeneyde@users.noreply.github.com>
Date: Tue, 16 Mar 2021 00:02:25 -0400
Subject: [PATCH] bpo-41361: Optimized argument parsing for deque_rotate
 (GH-24796)

---
 .../2021-03-13-08-18-01.bpo-41361.lXDIlr.rst        |  1 +
 Modules/_collectionsmodule.c                        | 13 ++++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Library/2021-03-13-08-18-01.bpo-41361.lXDIlr.rst

diff --git a/Misc/NEWS.d/next/Library/2021-03-13-08-18-01.bpo-41361.lXDIlr.rst b/Misc/NEWS.d/next/Library/2021-03-13-08-18-01.bpo-41361.lXDIlr.rst
new file mode 100644
index 00000000000..19e08f810bb
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-03-13-08-18-01.bpo-41361.lXDIlr.rst
@@ -0,0 +1 @@
+:meth:`~collections.deque.rotate` calls are now slightly faster due to faster argument parsing.
\ No newline at end of file
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 90bafb0ea86..ca63f710cd8 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -880,9 +880,20 @@ deque_rotate(dequeobject *deque, PyObject *const *args, Py_ssize_t nargs)
 {
     Py_ssize_t n=1;
 
-    if (!_PyArg_ParseStack(args, nargs, "|n:rotate", &n)) {
+    if (!_PyArg_CheckPositional("deque.rotate", nargs, 0, 1)) {
         return NULL;
     }
+    if (nargs) {
+        PyObject *index = _PyNumber_Index(args[0]);
+        if (index == NULL) {
+            return NULL;
+        }
+        n = PyLong_AsSsize_t(index);
+        Py_DECREF(index);
+        if (n == -1 && PyErr_Occurred()) {
+            return NULL;
+        }
+    }
 
     if (!_deque_rotate(deque, n))
         Py_RETURN_NONE;