fix issue with @supports --css rule + skip duplicates in mq

Author: claudia-romano

index.js

@@ -231,24 +231,23 @@ module.exports = postcss.plugin('postcss-css-variables', function(options) {
 		// Collect all the rules that have declarations that use variables
 		var rulesThatHaveDeclarationsWithVariablesList = [];
 		css.walkRules(function(rule) {
-			if(ruleIsInCssSupportsRule(rule)) {
-				return false;
-			}
-			var doesRuleUseVariables = rule.nodes.some(function(node) {
-				if(node.type === 'decl') {
-					var decl = node;
-					// If it uses variables
-					// and is not a variable declarations that we may be preserving from earlier
-					if(resolveValue.RE_VAR_FUNC.test(decl.value) && !RE_VAR_PROP.test(decl.prop)) {
-						return true;
+			if(!ruleIsInCssSupportsRule(rule)) {
+				var doesRuleUseVariables = rule.nodes.some(function(node) {
+					if(node.type === 'decl') {
+						var decl = node;
+						// If it uses variables
+						// and is not a variable declarations that we may be preserving from earlier
+						if(resolveValue.RE_VAR_FUNC.test(decl.value) && !RE_VAR_PROP.test(decl.prop)) {
+							return true;
+						}
 					}
-				}
 
-				return false;
-			});
+					return false;
+				});
 
-			if(doesRuleUseVariables) {
-				rulesThatHaveDeclarationsWithVariablesList.push(rule);
+				if(doesRuleUseVariables) {
+					rulesThatHaveDeclarationsWithVariablesList.push(rule);
+				}
 			}
 		});
 

lib/resolve-decl.js

@@ -14,6 +14,7 @@ var cloneSpliceParentOntoNodeWhen = require('./clone-splice-parent-onto-node-whe
 function eachMapItemDependencyOfDecl(variablesUsedList, map, decl, cb) {
 	// Now find any at-rule declarations that pertains to each rule
 	// Loop through the variables used
+	var previousDecl = '';
 	variablesUsedList.forEach(function(variableUsedName) {
 
 		// Find anything in the map that corresponds to that variable
@@ -60,7 +61,11 @@ function eachMapItemDependencyOfDecl(variablesUsedList, map, decl, cb) {
 			// If it is under the proper scope,
 			// we need to check because we are iterating over all map entries
 			if(mimicDecl && isNodeUnderScope(mimicDecl, mapItem.parent, true)) {
-				cb(mimicDecl, mapItem);
+				//double check the declaration is not exactly the same as the previous one -> prevent diplicated blocks in mq
+				if( previousDecl != JSON.stringify(mimicDecl) ) {
+					cb(mimicDecl, mapItem);
+				}
+				previousDecl = JSON.stringify(mimicDecl);
 			}
 		});
 	});