231870 - instanceof Event (well, any dom object) is broken - throws instead of returning false

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect, P3)

Description

[timeless]

Steps:
1. start writing something which is supposed to analyze objects and write:

function analyze(o){
if (o instanceof Event){
return "something";
}
return o;
}

/*then call it*/
analyze("test","case");

expected result:
analyze returns "test" (actual code is slightly more complicated)

actual result:
Error: uncaught exception: null

another example from venkman:
0001: "String" instanceof Node
Caught exception: “null”

--
<peterv> just file a bug
<Neil> nah, none of the primitives work
<Neil> eww, not even [] or {} work
<peterv> timeless: does it happen with other DOM classes?
<peterv> well, it seems to do the same with Node
<peterv> any one
<Neil> and element
<Neil> you can do (dom object) instanceof (dom type)
<peterv> so it's in my hasinstance code
<peterv> file it in DOM Other or whatever
<peterv> assign it directly to me

Comment 1

[Peter Van der Beken [:peterv]]

Attachment: Fix

Comment 2

[Johnny Stenback (:jst)]

Comment on attachment 139691 [details] [diff] [review]
Fix

+  if (JSVAL_IS_PRIMITIVE(v) || JSVAL_IS_VOID(v)) {
+    return JS_TRUE;
   }

undefined is a primitive, so JSVAL_IS_PRIMITIVE(v) will be true if v is
undefined. No need to check if JSVAL_IS_VOID(v).

+  JSObject *dom_obj = JSVAL_TO_OBJECT(v);
   if (!dom_obj) {
-    return JS_TRUE;
+    NS_ERROR("DOMJSClass_HasInstance couldn't get object");
+    nsDOMClassInfo::ThrowJSException(cx, NS_ERROR_UNEXPECTED);
+
+    return JS_FALSE;

Not necessary, if v is null, it's primitive, so you'll never get here. If you
want to assert, that's fine, but no need to check.

r+sr=jst with that fixed.

Comment 3

[Peter Van der Beken [:peterv]]

Checked in.