fix($compile): merge attributes safely to avoid upsetting IE8

src/ng/compile.js

@@ -383,7 +383,10 @@ function $CompileProvider($provide) {
           if (writeAttr !== false) {
             if (value === null || value === undefined) {
               this.$$element.removeAttr(attrName);
-            } else {
+            } else if (value !== this.$$element.attr(attrName)) {
+              // Set new value only if it is not already there, avoiding
+              // issues with IE, where certain attributes cannot be set
+              // on in-document elements, e.g. 'type' on <input>
               this.$$element.attr(attrName, value);
             }
           }
@@ -1130,8 +1133,9 @@ function $CompileProvider($provide) {
       // reapply the old attributes to the new element
       forEach(dst, function(value, key) {
         if (key.charAt(0) != '$') {
-          if (src[key]) {
-            value += (key === 'style' ? ';' : ' ') + src[key];
+          var srcVal = src[key];
+          if (srcVal && srcVal !== value) {
+            value += (key === 'style' ? ';' : ' ') + srcVal;
           }
           dst.$set(key, value, true, srcAttr[key]);
         }

test/ng/compileSpec.js

@@ -489,6 +489,14 @@ describe('$compile', function() {
               expect(element).toBe(attr.$$element);
             }
           }));
+          directive('replaceWithArbitraryAttribute', valueFn({
+            replace: true,
+            template: '<div data-foo="bar">With data-foo</div>',
+            compile: function(element, attr) {
+              attr.$set('compiled', 'COMPILED');
+              expect(element).toBe(attr.$$element);
+            }
+          }));
         }));
 
 
@@ -538,6 +546,14 @@ describe('$compile', function() {
           expect(div.attr('high-log')).toEqual('');
         }));
 
+        it('should preserve identical attributes when merging', inject(function($compile, $rootScope) {
+          element = $compile(
+            '<div><div replace-with-arbitrary-attribute data-foo="bar"/><div>')
+            ($rootScope);
+          var div = element.find('div');
+          expect(div.attr('data-foo')).toBe('bar');
+        }));
+
         it('should prevent multiple templates per element', inject(function($compile) {
           try {
             $compile('<div><span replace class="replace"></span></div>');