fix spacing issue with extends and fix tests

lib/less/parser.js

@@ -49,7 +49,7 @@ less.Parser = function Parser(env) {
         chunks,      // chunkified input
         current,     // index of current chunk, in `input`
         parser,
-        rootFilename = env.filename;
+        rootFilename = env && env.filename;
 
     // Top parser on an import tree must be sure there is one "env"
     // which will then be passed around by reference.
@@ -1278,7 +1278,7 @@ less.Parser = function Parser(env) {
                     $(this.comments);
                     if (! $(',')) { break; }
                     if (s.condition) {
-                        error("Guards are only currently allowed on a single selector. ");
+                        error("Guards are only currently allowed on a single selector.");
                     }
                     $(this.comments);
                 }

lib/less/tree/extend.js

@@ -30,9 +30,16 @@ tree.Extend.prototype = {
     },
     findSelfSelectors: function (selectors) {
         var selfElements = [],
-            i;
+            i,
+            selectorElements;
 
         for(i = 0; i < selectors.length; i++) {
+            selectorElements = selectors[i].elements;
+            // duplicate the logic in genCSS function inside the selector node.
+            // future TODO - move both logics into the selector joiner visitor
+            if (i > 0 && selectorElements.length && selectorElements[0].combinator.value === "") {
+                selectorElements[0].combinator.value = ' ';
+            }
             selfElements = selfElements.concat(selectors[i].elements);
         }
 

test/less/errors/multiple-guards-on-css-selectors.txt

@@ -1,4 +1,4 @@
-SyntaxError: Guards are only currently allowed on a single selector.  in {path}multiple-guards-on-css-selectors.less on line 3, column 1:
+SyntaxError: Guards are only currently allowed on a single selector. in {path}multiple-guards-on-css-selectors.less on line 3, column 1:
 2 .a when (@ie8 = true),
 3 .b {
 4 }