736805 - "new X instanceof X" fails in Web Console

Status: RESOLVED INACTIVE

(Core :: XPConnect, defect)

Description

[Masatoshi Kimura [:emk]]

Steps to reproduce:
1. Press Ctrl+K to open Web Console.
2. Type "new MozBlobBuilder().getBlob() instanceof Blob" (without quote) and press Enter.
Actual result:
false
Expected result:
true

It works as expected in Web pages. It also works if I reverted <https://hg.mozilla.org/mozilla-central/rev/95a8eba120fe>.

Comment 1

[Masatoshi Kimura [:emk]]

This bug was not specific to Blob. "new MozBlobBuilder instanceof MozBlobBuilder" also returns false in Web Console.
OTOH, "new Array instanceof Array" returns true.

Comment 2

[Josh Matthews [:jdm]]

This may be related to bug 690529.

Comment 3

[Masatoshi Kimura [:emk]]

a = new window.Array
[]
a instanceof Array
false
a instanceof window.Array
true
bb = new window.MozBlobBuilder
[object MozBlobBuilder]
bb instanceof window.MozBlobBuilder
false

At least it should return consistent results.

Comment 4

[Boris Zbarsky [:bzbarsky]]

This has nothing to do with the DOM per se; there are various security wrappers and whatnot all over here.

Comment 5

[Masatoshi Kimura [:emk]]

Works for me now, leaving open to track adding a regression test.

Comment 6

[BMO Automation]

Per policy at https://wiki.mozilla.org/Bug_Triage/Projects/Bug_Handling/Bug_Husbandry#Inactive_Bugs. If this bug is not an enhancement request or a bug not present in a supported release of Firefox, then it may be reopened.