On Thu, Jul 18, 2013 at 1:55 AM, Jonas Sicking <jonas at sicking.cc> wrote:

> On Wed, Jul 17, 2013 at 4:42 PM, Brandon Benvie <bbenvie at mozilla.com>
> wrote:
> > On 7/17/2013 4:36 PM, Jonas Sicking wrote:
> >>
> >> Is this simply a SpiderMonkey bug? Do we expect JS code to be able to
> >> handle Date objects representing timezones other than the user's
> >> current timezone?
> >
> >
> > What happens if the timezone changes between the creation of two Date
> > objects, such as for daylight savings or the user changes their system
> > timezone?
>
> I believe SpiderMonkey in Firefox Desktop until recently would grab
> the snapshot of the user's timezone on browser startup, and then never
> change it until the browser was shut down.
>
> Now it seems to update that snapshot now and then in some pattern that
> isn't obvious to me. When that happens the timezone offset for *all*
> Date instances all change.
>
>
We update the timezone info each time a new global is created:
http://mxr.mozilla.org/mozilla-central/source/js/src/jscompartment.cpp#90
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20130718/6c030855/attachment.html>

On Thu, Jul 18, 2013 at 1:55 AM, Jonas Sicking <jonas at sicking.cc> wrote:

> I believe SpiderMonkey in Firefox Desktop until recently would grab
> the snapshot of the user's timezone on browser startup, and then never
> change it until the browser was shut down.
>
> Now it seems to update that snapshot now and then in some pattern that
> isn't obvious to me. When that happens the timezone offset for *all*
> Date instances all change.

We update the timezone info each time a new global is created:
http://mxr.mozilla.org/mozilla-central/source/js/src/jscompartment.cpp#90