From d1f0a1ce9c0fb6ed70f6e1b0964e3bdfc8c15b04 Mon Sep 17 00:00:00 2001
From: "mergify[bot]" <37929162+mergify[bot]@users.noreply.github.com>
Date: Wed, 21 Feb 2024 07:05:51 -0500
Subject: [PATCH] Improve performance of custom-iterator `__getitem__` (#1096)
 (#1100)

Flipping the order of `Slice` and `Int` in `SliceOrInt` so that `Int`
comes first means that the `FromPyObject` derivation will then try `Int`
first, which is the correct variant in like 99.9% of uses of the struct.
This has the impact of improving int `__getitem__` times in the custom
iterators by about 3x (from 205ns to 61ns on my machine), which has
knock-on effects for the implicit iterators Python defines for these
classes.

(cherry picked from commit d4f28e35f6ee5f76a26e16e0ffc357bb72bb89da)

Co-authored-by: Jake Lishman <jake.lishman@ibm.com>
---
 src/iterators.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/iterators.rs b/src/iterators.rs
index 86e894ff5..7217c9b63 100644
--- a/src/iterators.rs
+++ b/src/iterators.rs
@@ -411,8 +411,8 @@ trait PyGCProtocol {
 
 #[derive(FromPyObject)]
 enum SliceOrInt<'a> {
-    Slice(&'a PySlice),
     Int(isize),
+    Slice(&'a PySlice),
 }
 
 trait PyConvertToPyArray {