Try harder to find a scope chain so that we can report exceptions when there is no code running currently. bug 390160, r=brendan sr=jst a=brendan

js/src/jsapi.c

@@ -1664,8 +1664,24 @@ JS_GetScopeChain(JSContext *cx)
 
     fp = cx->fp;
     if (!fp) {
-        JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_INACTIVE);
-        return NULL;
+        /*
+         * There is no code active on this context. In place of an actual
+         * scope chain, use the context's global object, which is set in
+         * js_InitFunctionAndObjectClasses, and which represents the default
+         * scope chain for the embedding. See also js_FindClassObject.
+         *
+         * For embeddings that use the inner and outer object hooks, the inner
+         * object represents the ultimate global object, with the outer object
+         * acting as a stand-in.
+         */
+        JSObject *obj = cx->globalObject;
+        if (!obj) {
+            JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_INACTIVE);
+            return NULL;
+        }
+
+        OBJ_TO_INNER_OBJECT(cx, obj);
+        return obj;
     }
     return js_GetScopeChain(cx, fp);
 }