[egenix-users] date display behavior in mxdatetime 3

[M.-A. Lemburg]

On 2008-02-29 20:58, M.-A. Lemburg wrote:
> On 2008-02-29 20:51, Eugene Chow wrote:
>> I've noticed that date display behavior has changed in version 3 of
>> mxdatetime in an undesirable way:
>>
>> Python 2.4.3 (#1, Apr  7 2006, 10:54:33)
>> [GCC 4.0.1 (Apple Computer, Inc. build 5250)] on darwin
>> Type "help", "copyright", "credits" or "license" for more information.
>>>>> import mx.DateTime
>>>>> mx.DateTime.__version__
>> '3.0.0'
>>>>> d=mx.DateTime.Date(2008,1,-1)
>>>>> d
>> <mx.DateTime.DateTime object for '2008-01--1 00:00:00.00' at 63e90>
>>>>> d.strftime()
>> 'Thu Jan -1 00:00:00 2008'
>>>>> d==mx.DateTime.Date(2008,1,31)
>> True
>> In version 2, the day is displayed as the actual last day of the month
>> and not "-1".
>>
>> Was this change intentional?
> 
> No, that's a bug. Thanks for reporting it. We'll fix it in 3.0.1.

That appears to be a GCC compiler optimizer - the normalization seems
to have been "optimized" away.

By adding this patch (which does really do anything):

Index: mxDateTime.c
===================================================================
--- mxDateTime.c        (revision 22888)
+++ mxDateTime.c        (working copy)
@@ -1022,6 +1022,9 @@
        DPRINTF("mxDateTime_SetFromDateAndTime: "
                "yearoffset=%ld absdate=%ld\n",
                yearoffset,absdate);
+       DPRINTF("mxDateTime_SetFromDateAndTime: using normalized values:"
+               "year=%i month=%i day=%i\n",
+               year,month,day);

        datetime->absdate = absdate;

the correct result gets used:

>>> import mx.DateTime
>>> mx.DateTime.Date(2008,1,-1).day
31

We'll have to see how we can make GCC do the right thing in all
cases and add a test case for this.

Thanks,
-- 
Marc-Andre Lemburg
eGenix.com

Professional Python Services directly from the Source  (#1, Feb 29 2008)
>>> Python/Zope Consulting and Support ...        http://www.egenix.com/
>>> mxODBC.Zope.Database.Adapter ...             http://zope.egenix.com/
>>> mxODBC, mxDateTime, mxTextTools ...        http://python.egenix.com/
________________________________________________________________________

:::: Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! ::::


   eGenix.com Software, Skills and Services GmbH  Pastor-Loeh-Str.48
    D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
           Registered at Amtsgericht Duesseldorf: HRB 46611