From bc1845a8f86ed14c8f6bb99e7df752a6894b3f55 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Tue, 15 Aug 2023 00:51:30 +0200
Subject: [PATCH] style: Fix hue adjustment to match the spec

The value to sum is tau, not pi. This was caught by some tests, see
https://drafts.csswg.org/css-color/#shorter

Differential Revision: https://phabricator.services.mozilla.com/D147006
---
 components/style/values/animated/color.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/components/style/values/animated/color.rs b/components/style/values/animated/color.rs
index d3ee616f765..a7dba508f68 100644
--- a/components/style/values/animated/color.rs
+++ b/components/style/values/animated/color.rs
@@ -432,9 +432,9 @@ fn adjust_hue(left: &mut f32, right: &mut f32, hue_interpolation: HueInterpolati
             let delta = *right - *left;
 
             if delta > PI {
-                *left += PI;
-            } else if delta < -1. * PI {
-                *right += PI;
+                *left += TAU;
+            } else if delta < -PI {
+                *right += TAU;
             }
         },
         // https://drafts.csswg.org/css-color/#longer