From 7cd41518c9f6233a7558e5bf20b08df0c67fbf14 Mon Sep 17 00:00:00 2001
From: Hiroyuki Ikezoe <hikezoe@mozilla.com>
Date: Wed, 13 Jun 2018 06:42:14 +0900
Subject: [PATCH] Bug 1468294 - Double f64::EPSILON for calculation error.
 r=birtles

It's possible that both this_weight and other_weght have calculation errors
which are approximately equal to f64::EPSILON.

MozReview-Commit-ID: 8OddG9rI3qd

--HG--
extra : rebase_source : 9c22d17dcfb8efea7276864502344dc4981c358a
---
 dom/animation/test/crashtests/1468294-1.html               | 7 +++++++
 dom/animation/test/crashtests/crashtests.list              | 1 +
 .../style/properties/helpers/animated_properties.mako.rs   | 4 +++-
 3 files changed, 11 insertions(+), 1 deletion(-)
 create mode 100644 dom/animation/test/crashtests/1468294-1.html

diff --git a/dom/animation/test/crashtests/1468294-1.html b/dom/animation/test/crashtests/1468294-1.html
new file mode 100644
index 000000000000..e4092046ac2d
--- /dev/null
+++ b/dom/animation/test/crashtests/1468294-1.html
@@ -0,0 +1,7 @@
+<script>
+addEventListener("DOMContentLoaded", () => {
+  document.documentElement.animate([{ "transform": "matrix(2,1,1,5,2,8)" }],
+                                    { duration: 1000,
+                                      easing: "cubic-bezier(1,-15,.6,4)" });
+})
+</script>
diff --git a/dom/animation/test/crashtests/crashtests.list b/dom/animation/test/crashtests/crashtests.list
index ec5261c0f22c..11f53bf485b6 100644
--- a/dom/animation/test/crashtests/crashtests.list
+++ b/dom/animation/test/crashtests/crashtests.list
@@ -40,3 +40,4 @@ pref(dom.animations-api.core.enabled,true) load 1393605-1.html
 load 1400022-1.html
 pref(dom.animations-api.core.enabled,true) load 1401809.html
 pref(dom.animations-api.core.enabled,true) load 1411318-1.html
+load 1468294-1.html
diff --git a/servo/components/style/properties/helpers/animated_properties.mako.rs b/servo/components/style/properties/helpers/animated_properties.mako.rs
index d935726eb486..de0e48c782d6 100644
--- a/servo/components/style/properties/helpers/animated_properties.mako.rs
+++ b/servo/components/style/properties/helpers/animated_properties.mako.rs
@@ -1739,7 +1739,9 @@ impl Animate for Quaternion {
 
         let (this_weight, other_weight) = procedure.weights();
         debug_assert!(
-            (this_weight + other_weight - 1.0f64).abs() <= f64::EPSILON ||
+            // Doule EPSILON since both this_weight and other_weght have calculation errors
+            // which are approximately equal to EPSILON.
+            (this_weight + other_weight - 1.0f64).abs() <= f64::EPSILON * 2.0 ||
             other_weight == 1.0f64 || other_weight == 0.0f64,
             "animate should only be used for interpolating or accumulating transforms"
         );