From f6e2ac013ab1a00369b6e4c3293e931b9205ef7a Mon Sep 17 00:00:00 2001
From: ysds <ysds.code@gmail.com>
Date: Sat, 14 Mar 2020 16:56:47 +0900
Subject: [PATCH 1/3] Prevent redundant 'none' for prefers-reduced-motion

---
 scss/mixins/_transition.scss | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/scss/mixins/_transition.scss b/scss/mixins/_transition.scss
index 54983d736c59..6fe9d32a61e5 100644
--- a/scss/mixins/_transition.scss
+++ b/scss/mixins/_transition.scss
@@ -1,13 +1,13 @@
 // stylelint-disable property-blacklist
 @mixin transition($transition...) {
+  @if length($transition) == 0 {
+    $transition: $transition-base;
+  }
+
   @if $enable-transitions {
-    @if length($transition) == 0 {
-      transition: $transition-base;
-    } @else {
-      transition: $transition;
-    }
+    transition: $transition;
 
-    @if $enable-prefers-reduced-motion-media-query {
+    @if $enable-prefers-reduced-motion-media-query and nth($transition, 1) != null and nth($transition, 1) != none {
       @media (prefers-reduced-motion: reduce) {
         transition: none;
       }

From a3130a0d5c9d15b0e805bf74d42ac691b80a6acc Mon Sep 17 00:00:00 2001
From: ysds <ysds.code@gmail.com>
Date: Sat, 14 Mar 2020 17:00:18 +0900
Subject: [PATCH 2/3] Output warning when use 'none' or 'null' with multiple
 arguments

---
 scss/mixins/_transition.scss | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/scss/mixins/_transition.scss b/scss/mixins/_transition.scss
index 6fe9d32a61e5..e947836c0abe 100644
--- a/scss/mixins/_transition.scss
+++ b/scss/mixins/_transition.scss
@@ -4,6 +4,14 @@
     $transition: $transition-base;
   }
 
+  @if length($transition) > 1 {
+    @each $value in $transition {
+      @if $value == null or $value == none {
+        @warn "The keyword 'none' or 'null' must be used as a single argument.";
+      }
+    }
+  }
+
   @if $enable-transitions {
     transition: $transition;
 

From 2c5e03961abf4a9982ed989f8c7388b516bfc722 Mon Sep 17 00:00:00 2001
From: ysds <ysds.code@gmail.com>
Date: Sun, 15 Mar 2020 00:17:56 +0900
Subject: [PATCH 3/3] Fix for libsass(node-sass)

---
 scss/mixins/_transition.scss | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/scss/mixins/_transition.scss b/scss/mixins/_transition.scss
index e947836c0abe..54553deb9c67 100644
--- a/scss/mixins/_transition.scss
+++ b/scss/mixins/_transition.scss
@@ -13,7 +13,9 @@
   }
 
   @if $enable-transitions {
-    transition: $transition;
+    @if nth($transition, 1) != null {
+      transition: $transition;
+    }
 
     @if $enable-prefers-reduced-motion-media-query and nth($transition, 1) != null and nth($transition, 1) != none {
       @media (prefers-reduced-motion: reduce) {