fix(zone): fix #674, handle error.stack readonly case (#675)

lib/zone.ts

@@ -1747,7 +1747,7 @@ const Zone: ZoneType = (function(global: any) {
     'long-stack-trace'
   ];
 
-  function attachZoneAndRemoveInternalZoneFrames(error: any) {
+  function attachZoneAndRemoveInternalZoneFrames(error: any, zoneAwareError: any) {
     // Save original stack trace
     error.originalStack = error.stack;
     // Process the stack trace and rewrite the frames.
@@ -1789,7 +1789,14 @@ const Zone: ZoneType = (function(global: any) {
           }
         }
       }
-      error.stack = error.zoneAwareStack = frames.join('\n');
+      const finalStack: string = frames.join('\n');
+      try {
+        error.stack = error.zoneAwareStack = finalStack;
+      } catch (nonWritableErr) {
+        // in some browser, the error.stack is readonly such as PhantomJS
+        // so we need to store the stack frames to zoneAwareError directly
+        zoneAwareError.stack = finalStack;
+      }
     }
   }
 
@@ -1820,7 +1827,7 @@ const Zone: ZoneType = (function(global: any) {
     this[__symbol__('error')] = error;
     // 1. attach zone information to stack frame
     // 2. remove zone internal stack frames
-    attachZoneAndRemoveInternalZoneFrames(error);
+    attachZoneAndRemoveInternalZoneFrames(error, this);
 
     // use defineProperties here instead of copy property value
     // because of issue #595 which will break angular2.

test/common/Error.spec.ts

@@ -405,4 +405,24 @@ describe('Error stack', () => {
                         }, null, () => null, null);
        task.invoke();
      }));
+
+  it('should be able to generate zone free stack even NativeError stack is readonly', function() {
+    const _global: any =
+        typeof window === 'object' && window || typeof self === 'object' && self || global;
+    const NativeError = _global['__zone_symbol__Error'];
+    const desc = Object.getOwnPropertyDescriptor(NativeError.prototype, 'stack');
+    if (desc) {
+      const originalSet: (value: any) => void = desc.set;
+      // make stack readonly
+      desc.set = null;
+
+      try {
+        const error = new Error('test error');
+        expect(error.stack).toBeTruthy();
+        assertStackDoesNotContainZoneFrames(error);
+      } finally {
+        desc.set = originalSet;
+      }
+    }
+  });
 });