[Webkit-unassigned] [Bug 11157] REGRESSION (r16780): Date conversion to local time gets the DST flag wrong for some dates

[bugzilla-daemon at webkit.org]

http://bugs.webkit.org/show_bug.cgi?id=11157


kmccullough at apple.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|                            |LATER
           Keywords|                            |InRadar
             Status|REOPENED                    |RESOLVED




------- Comment #5 from kmccullough at apple.com  2006-10-11 12:47 PDT -------
<rdar://4777813>

There are several issues here:
1) Dates that shouldn't exist: for example 
April 25th 1982 2:30am Pacific
because DST happens exactly at 2am, it skipps to 3am and 2:30am should never
happen

2) Dates that happen twice: for example
Oct 31, 1982 1:30am PST/PDT
because DST makes 2am go back to 1am, the hour from 1am to 2am will happen
twice

3) The History of DST: Some locations did not observer DST for some times (as
seen by the command zdump)

Here is a summary of our resolutions
3) According to the spec, history should not take into account what really
happened but interpolate from a comparable year, where comparable years are
judged by when Jan 1 happens and if the year is a leap year.
This will only happen for dates that fall outside of the 1970-2038 range. if
you fall out of that range then you are offset to a comparable year.
This is consistent with what most browsers.

2) To address dates that happen twice, the standard behavior is to pick
Standard Time (or the second time the time happens)

1) The final issue is what to do with times that should not have happened. 
Some browsers just show the time and some subtract an hour (e.g. 2am becomes
1am).  What we think should happen is that an hour should be added (e.g. 2am
becomes 3am).  This has been added as a bug in Radar (number is at the top of
this comment)


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