From d213d46385a366ea7a265835a1aa17e0e29e1aea Mon Sep 17 00:00:00 2001
From: Jakub Pawlowicz <contact@jakubpawlowicz.com>
Date: Sat, 9 Apr 2016 17:18:15 +0200
Subject: [PATCH] Fixes #754 - treats empty rule as unmergeable.

Firefox and Chrome just ignore such rules while IE ignores empty rule
and interprets the rest correctly. This means it could be used as a
IE hack.
---
 History.md                                        | 1 +
 lib/utils/compatibility.js                        | 6 +++---
 test/selectors/merge-adjacent-test.js             | 8 ++++++++
 test/selectors/merge-non-adjacent-by-body-test.js | 4 ++++
 test/selectors/restructure-test.js                | 4 ++++
 5 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/History.md b/History.md
index 6f6980c8..878954f4 100644
--- a/History.md
+++ b/History.md
@@ -7,6 +7,7 @@
 ==================
 
 * Fixed issue [#734](https://github.com/jakubpawlowicz/clean-css/issues/734) - `--root` option edge case.
+* Fixed issue [#758](https://github.com/jakubpawlowicz/clean-css/issues/758) - treats empty rule as unmergeable.
 
 [3.4.11 / 2016-04-01](https://github.com/jakubpawlowicz/clean-css/compare/v3.4.10...v3.4.11)
 ==================
diff --git a/lib/utils/compatibility.js b/lib/utils/compatibility.js
index 5c8ee2b2..25bb5311 100644
--- a/lib/utils/compatibility.js
+++ b/lib/utils/compatibility.js
@@ -22,7 +22,7 @@ var DEFAULTS = {
     selectors: {
       adjacentSpace: false, // div+ nav Android stock browser hack
       ie7Hack: false, // *+html hack
-      special: /(\-moz\-|\-ms\-|\-o\-|\-webkit\-|:dir\([a-z-]*\)|:first(?![a-z-])|:fullscreen|:left|:read-only|:read-write|:right|:placeholder|:host|::content|\/deep\/|::shadow)/ // special selectors which prevent merging
+      special: /(\-moz\-|\-ms\-|\-o\-|\-webkit\-|:dir\([a-z-]*\)|:first(?![a-z-])|:fullscreen|:left|:read-only|:read-write|:right|:placeholder|:host|::content|\/deep\/|::shadow|^,)/ // special selectors which prevent merging
     },
     units: {
       ch: true,
@@ -58,7 +58,7 @@ var DEFAULTS = {
     selectors: {
       adjacentSpace: false,
       ie7Hack: false,
-      special: /(\-moz\-|\-ms\-|\-o\-|\-webkit\-|:root|:nth|:first\-of|:last|:only|:empty|:target|:checked|::selection|:enabled|:disabled|:not|:placeholder|:host|::content|\/deep\/|::shadow)/
+      special: /(\-moz\-|\-ms\-|\-o\-|\-webkit\-|:root|:nth|:first\-of|:last|:only|:empty|:target|:checked|::selection|:enabled|:disabled|:not|:placeholder|:host|::content|\/deep\/|::shadow|^,)/
     },
     units: {
       ch: false,
@@ -94,7 +94,7 @@ var DEFAULTS = {
     selectors: {
       adjacentSpace: false,
       ie7Hack: true,
-      special: /(\-moz\-|\-ms\-|\-o\-|\-webkit\-|:focus|:before|:after|:root|:nth|:first\-of|:last|:only|:empty|:target|:checked|::selection|:enabled|:disabled|:not|:placeholder|:host|::content|\/deep\/|::shadow)/
+      special: /(\-moz\-|\-ms\-|\-o\-|\-webkit\-|:focus|:before|:after|:root|:nth|:first\-of|:last|:only|:empty|:target|:checked|::selection|:enabled|:disabled|:not|:placeholder|:host|::content|\/deep\/|::shadow|^,)/
     },
     units: {
       ch: false,
diff --git a/test/selectors/merge-adjacent-test.js b/test/selectors/merge-adjacent-test.js
index 69ccd9ca..df290e52 100644
--- a/test/selectors/merge-adjacent-test.js
+++ b/test/selectors/merge-adjacent-test.js
@@ -67,6 +67,14 @@ vows.describe('remove duplicates')
       'two rules with latter with suffix properties': [
         'a{display:none}a{display:none;visibility:hidden}',
         'a{display:none;visibility:hidden}'
+      ],
+      'no rule after comma': [
+        'h1{color:#000},h2{color:#000}',
+        'h1{color:#000},h2{color:#000}'
+      ],
+      'no rule after comma with comma last': [
+        'h1{color:#000}h2,{color:#000}',
+        'h1{color:#000},h2{color:#000}'
       ]
     })
   )
diff --git a/test/selectors/merge-non-adjacent-by-body-test.js b/test/selectors/merge-non-adjacent-by-body-test.js
index f7cbb564..9fb2c964 100644
--- a/test/selectors/merge-non-adjacent-by-body-test.js
+++ b/test/selectors/merge-non-adjacent-by-body-test.js
@@ -27,6 +27,10 @@ vows.describe('merge non djacent by body')
       'of element selectors with an empty class selector in between': [
         'p{color:red}.a{}div{color:red}',
         'div,p{color:red}'
+      ],
+      'no rule after comma': [
+        'h1{color:#000}div{color:red},h2{color:#000}',
+        'h1{color:#000}div{color:red},h2{color:#000}'
       ]
     })
   )
diff --git a/test/selectors/restructure-test.js b/test/selectors/restructure-test.js
index 32b234d2..0defa690 100644
--- a/test/selectors/restructure-test.js
+++ b/test/selectors/restructure-test.js
@@ -155,6 +155,10 @@ vows.describe('restructure')
       'with different vendor prefixed value group': [
         'a{-moz-box-sizing:content-box;box-sizing:content-box}div{color:red}p{-moz-box-sizing:content-box;-webkit-box-sizing:content-box;box-sizing:content-box}',
         'a{-moz-box-sizing:content-box;box-sizing:content-box}div{color:red}p{-moz-box-sizing:content-box;-webkit-box-sizing:content-box;box-sizing:content-box}'
+      ],
+      'no rule after comma': [
+        'h1{color:#000}div{color:red},h2{color:#000;display:block}',
+        'h1{color:#000}div{color:red},h2{color:#000;display:block}'
       ]
     })
   )
-- 
2.34.1