Bug 457310 - Don't potentially run code with an exception still on cx. r+sr=jst

js/src/jscntxt.h

@@ -931,13 +931,15 @@ class JSAutoTempValueRooter
         JS_POP_TEMP_ROOT(mContext, &mTvr);
     }
 
+  protected:
+    JSContext *mContext;
+
   private:
 #ifndef AIX
     static void *operator new(size_t);
     static void operator delete(void *, size_t);
 #endif
 
-    JSContext *mContext;
     JSTempValueRooter mTvr;
 };
 

js/src/xpconnect/src/xpcconvert.cpp

@@ -1397,6 +1397,25 @@ XPCConvert::ConstructException(nsresult rv, const char* message,
 
 /********************************/
 
+class AutoExceptionRestorer : public JSAutoTempValueRooter
+{
+public:
+    AutoExceptionRestorer(JSContext *cx, jsval v)
+        : JSAutoTempValueRooter(cx, v),
+          mVal(v)
+    {
+        JS_ClearPendingException(mContext);
+    }
+
+    ~AutoExceptionRestorer()
+    {
+        JS_SetPendingException(mContext, mVal);
+    }
+
+private:
+    jsval mVal;
+};
+
 // static
 nsresult
 XPCConvert::JSValToXPCException(XPCCallContext& ccx,
@@ -1406,6 +1425,7 @@ XPCConvert::JSValToXPCException(XPCCallContext& ccx,
                                 nsIException** exceptn)
 {
     JSContext* cx = ccx.GetJSContext();
+    AutoExceptionRestorer aer(cx, s);
 
     if(!JSVAL_IS_PRIMITIVE(s))
     {