Merge branch 'master' of https://github.com/cloudhead/less.js

lib/less/browser.js

@@ -118,13 +118,7 @@ function createCSS(styles, sheet, lastModified) {
     }
     css.id = id;
 
-    if (css.styleSheet) { // IE
-        try {
-            css.styleSheet.cssText = styles;
-        } catch (e) {
-            throw new(Error)("Couldn't reassign styleSheet.cssText.");
-        }
-    } else {
+    if (!css.styleSheet) {
         css.appendChild(document.createTextNode(styles));
 
         // If new contents match contents of oldCss, don't replace oldCss
@@ -148,6 +142,17 @@ function createCSS(styles, sheet, lastModified) {
         oldCss.parentNode.removeChild(oldCss);
     }
 
+    // For IE.
+    // This needs to happen *after* the style element is added to the DOM, otherwise IE 7 and 8 may crash.
+    // See http://social.msdn.microsoft.com/Forums/en-US/7e081b65-878a-4c22-8e68-c10d39c2ed32/internet-explorer-crashes-appending-style-element-to-head
+    if (css.styleSheet) {
+        try {
+            css.styleSheet.cssText = styles;
+        } catch (e) {
+            throw new(Error)("Couldn't reassign styleSheet.cssText.");
+        }
+    }
+
     // Don't update the local store if the file wasn't modified
     if (lastModified && cache) {
         log('saving ' + href + ' to cache.', logLevel.info);

lib/less/tree/mixin.js

@@ -283,7 +283,7 @@ tree.mixin.Definition.prototype = {
     matchCondition: function (args, env) {
         if (this.condition && !this.condition.eval(
             new(tree.evalEnv)(env,
-                [this.evalParams(env, new(tree.evalEnv)(env, this.frames.concat(env.frames)), args, [])] // the parameter variables
+                [this.evalParams(env, new(tree.evalEnv)(env, this.frames ? this.frames.concat(env.frames) : env.frames), args, [])] // the parameter variables
                     .concat(this.frames) // the parent namespace/mixin frames
                     .concat(env.frames)))) { // the current environment frames
             return false;

test/css/mixins-guards.css

@@ -88,3 +88,6 @@
   a: 1;
   x: 1;
 }
+.mixin-generated-class {
+  a: 1;
+}

test/less/mixins-guards.less

@@ -161,3 +161,13 @@
   }
 }
 .bug-100cm-1m(100cm);
+
+#ns {
+    .mixin-for-root-usage(@a) when (@a > 0) {
+        .mixin-generated-class {
+            a: @a;
+        }
+    }
+}
+
+#ns > .mixin-for-root-usage(1);