1370671 - Datepicker shows incorrect month for the first day of the month

Status: RESOLVED FIXED

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

Description

[David Smith]

Using URL: data:text/html,<input type="date" value="2017-06-01">

If the day of the month is 01, when you click on the datepicker, it shows the name of the prior month.  In the above case, it says that the datepicker is for May 2017, even though the days it shows are for June (first day of the month falling on Thursday, month is 30 days).

For the date "2017-06-02", it properly shows June 2017.  "2017-07-01" says it's still June. Etc.

In the case of "2017-01-01", it shows December 2016.

Comment 1

[Jessica Jong [:jessica] (inactive)]

Hmm, I couldn't reproduce this locally.
David, are you using Nightly? If possible, could you attach a video showing the steps and result?

+Scott to see if he knows what's going on.

Comment 2

[Scott Wu [:scottwu]]

Yes I see the problem now. It happens on some time zones but not others (All of US time zones but not in Europe). There was a similar issue with months caused by time zones and perhaps daylight time saving (Bug 1331608). Thanks for spotting this David, a patch is coming.

Comment 3

[Scott Wu [:scottwu]]

Attachment: Bug 1370671 - DateTimeFormat timeZone set to UTC to show correct year-month header for datepicker.

The datepicker is showing incorrect year-month header in some time zones, which
is similar to Bug 1331608. It's now fixed by setting the DateTimeFormat timeZone
to UTC. Also done the same thing to the year display for consistency.

Review commit: https://reviewboard.mozilla.org/r/146972/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/146972/

Comment 4

[Mike Conley (:mconley) (:⚙️)]

Comment on attachment 8875552 [details]
Bug 1370671 - DateTimeFormat timeZone set to UTC to show correct year-month header for datepicker.

https://reviewboard.mozilla.org/r/146972/#review152048

Great! Thanks!

Comment 5

[Scott Wu [:scottwu]]

Thanks Mike!

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d843dbc23708
DateTimeFormat timeZone set to UTC to show correct year-month header for datepicker. r=mconley

Comment 7

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/d843dbc23708