Fixes #1125 - quotes incorrectly stripped from @supports clause.

History.md

@@ -12,6 +12,7 @@
 * Fixed issue [#1087](https://github.com/jakubpawlowicz/clean-css/issues/1087) - allow units with any case.
 * Fixed issue [#1117](https://github.com/jakubpawlowicz/clean-css/issues/1117) - don't change zero values inside `min`, `max`, and `clamp` functions.
 * Fixed issue [#1122](https://github.com/jakubpawlowicz/clean-css/issues/1122) - don't wrap data URI in single quotes.
+* Fixed issue [#1125](https://github.com/jakubpawlowicz/clean-css/issues/1125) - quotes stripped from withing `@supports` clause.
 * Reworks all level 1 optimizations to conform to plugin style.
 
 [4.2.3 / 2020-01-28](https://github.com/jakubpawlowicz/clean-css/compare/v4.2.2...v4.2.3)

lib/optimizer/level-1/tidy-block.js

@@ -1,19 +1,22 @@
 var SUPPORTED_COMPACT_BLOCK_MATCHER = /^@media\W/;
+var SUPPORTED_QUOTE_REMOVAL_MATCHER = /^@(?:keyframes|-moz-keyframes|-o-keyframes|-webkit-keyframes)\W/;
 
 function tidyBlock(values, spaceAfterClosingBrace) {
   var withoutSpaceAfterClosingBrace;
+  var withoutQuotes;
   var i;
 
   for (i = values.length - 1; i >= 0; i--) {
     withoutSpaceAfterClosingBrace = !spaceAfterClosingBrace && SUPPORTED_COMPACT_BLOCK_MATCHER.test(values[i][1]);
+    withoutQuotes = SUPPORTED_QUOTE_REMOVAL_MATCHER.test(values[i][1]);
 
     values[i][1] = values[i][1]
       .replace(/\n|\r\n/g, ' ')
       .replace(/\s+/g, ' ')
       .replace(/(,|:|\() /g, '$1')
       .replace(/ \)/g, ')')
-      .replace(/'([a-zA-Z][a-zA-Z\d\-_]+)'/, '$1')
-      .replace(/"([a-zA-Z][a-zA-Z\d\-_]+)"/, '$1')
+      .replace(withoutQuotes ? /'([a-zA-Z][a-zA-Z\d\-_]+)'/ : null, '$1')
+      .replace(withoutQuotes ? /"([a-zA-Z][a-zA-Z\d\-_]+)"/ : null, '$1')
       .replace(withoutSpaceAfterClosingBrace ? /\) /g : null, ')');
   }
 

test/integration-test.js

@@ -2441,6 +2441,10 @@ vows.describe('integration tests')
         '@supports (display:flexbox){.flex{display:flexbox}}',
         '@supports (display:flexbox){.flex{display:flexbox}}'
       ],
+      '@supports with quoted text': [
+        '@supports (font-feature-settings:"liga" 0){html{--font:"font-with-features",helvetica,sans-serif}}',
+        '@supports (font-feature-settings:"liga" 0){html{--font:"font-with-features",helvetica,sans-serif}}'
+      ],
       '@-ms-viewport': [
         '@-ms-viewport{width:device-width}',
         '@-ms-viewport{width:device-width}'