[ python-Bugs-1656559 ] I think, I have found this bug on time.mktime()
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Tue Feb 13 16:54:05 CET 2007
Bugs item #1656559, was opened at 2007-02-10 04:41
Message generated for change (Comment added) made by loewis
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Category: None
>Group: 3rd Party
>Status: Closed
>Resolution: Invalid
Priority: 5
Private: No
Submitted By: Sérgio Monteiro Basto (sergiomb)
Assigned to: Nobody/Anonymous (nobody)
Summary: I think, I have found this bug on time.mktime()
Initial Comment:
well, I think, I have found this bug on time.mktime() for dates less
than 1976-09-26
when I do stringtotime of 1976-09-25
print "timeint %d" % time.mktime(__extract_date(m) + __extract_time(m) + (0, 0, 0))
extract date = 1976 9 25
extract time = 0 0 0
timeint 212454000
and
timetostring(212454000) = 1976-09-24T23:00:00Z !?
To be honest the date that kept me the action was the 1-1-1970 that
appears 31-12-1969. After timetostring(stringtotime(date)))
I made the test and time.mktime got a bug when date is less than
1976-09-26
see:
for 1976-09-27T00:00:00Z time.mktime gives 212630400
for 1976-09-26T00:00:00Z time.mktime gives 212544000
for 1976-09-25T00:00:00Z time.mktime gives 212454000
212630400 - 212544000 = 86400 (seconds) , one day correct !
but
212544000 - 212454000 = 90000 (seconds), one day more 3600 (seconds),
more one hour ?!?
--
Sérgio M. B.
----------------------------------------------------------------------
>Comment By: Martin v. Löwis (loewis)
Date: 2007-02-13 16:54
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cvalente, thanks for the research. Making a second attempt at closing this
as third-party bug.
----------------------------------------------------------------------
Comment By: Sérgio Monteiro Basto (sergiomb)
Date: 2007-02-13 15:25
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ok bug openned on
http://sources.redhat.com/bugzilla/show_bug.cgi?id=4033
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Comment By: Claudio Valente (cvalente)
Date: 2007-02-13 13:47
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OK. This is almost surely NOT a Python bug but most likely a libc bug.
In c:
----------
#include <time.h>
#include <stdio.h>
int main(int argc, char* argv[]){
struct tm t1;
struct tm t2;
/* midnight 26/SET/1076*/
t1.tm_sec = 0;
t1.tm_min = 0;
t1.tm_hour = 0;
t1.tm_mday = 26;
t1.tm_mon = 8;
t1.tm_year = 76;
/* midnight 25/SET/1076*/
t2.tm_sec = 0;
t2.tm_min = 0;
t2.tm_hour = 0;
t2.tm_mday = 25;
t2.tm_mon = 8;
t2.tm_year = 76;
printf("%li\n", mktime(&t1)-mktime(&t2));
printf("%li\n", mktime(&t1)-mktime(&t2));
return 0;
}
------
Outputs:
90000
86400
In perl:
-----
perl -le 'use POSIX; $t1=POSIX::mktime(0,0,0,26,8,76)
-POSIX::mktime(0,0,0,25,8,76); $t2 = POSIX::mktime(0,0,0,26,8,76)
-POSIX::mktime(0,0,0,25,8,76) ; print $t1."\n". $t2'
-----
Outputs
90000
86400
-----
My system is gentoo with glibc 2.4-r4
and my timezone is:
/usr/share/zoneinfo/Europe/Lisbon
When I changed this to another timezone (Say London) the problem didn't
exist.
Thank you all for your time.
----------------------------------------------------------------------
Comment By: Sérgio Monteiro Basto (sergiomb)
Date: 2007-02-13 13:22
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timezone : WET in winter WEST in summer
I try same with timezone of NEW YORK and
>>>
time.mktime((1976,9,26,0,0,0,0,0,0))-time.mktime((1976,9,25,0,0,0,0,0,0))
86400.0
----------------------------------------------------------------------
Comment By: Claudio Valente (cvalente)
Date: 2007-02-13 13:07
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I have the smae problem.
My system info is:
Python 2.4.3 (#1, Oct 18 2006, 16:42:32)
[GCC 4.1.1 (Gentoo 4.1.1)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
my libc version is 2.4-r4.
I'll try to run the analogous program in C and see whether this is a bug
of libc and not python.
More info later on.
----------------------------------------------------------------------
Comment By: Martin v. Löwis (loewis)
Date: 2007-02-13 13:04
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Also, don't change the priority of bugs.
----------------------------------------------------------------------
Comment By: Martin v. Löwis (loewis)
Date: 2007-02-13 13:04
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Please take a look at the implementation of mktime, and reformulate it as
a C program. This should demonstrate you that the bug is not in Python, but
in the C library.
Also please respond to the question what timezone you are in.
----------------------------------------------------------------------
Comment By: Sérgio Monteiro Basto (sergiomb)
Date: 2007-02-13 12:28
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Very strange !
>>> import time
>>> time.mktime((1976,9,26,0,0,0,0,0,0))
212544000.0
>>>
time.mktime((1976,9,26,0,0,0,0,0,0))-time.mktime((1976,9,25,0,0,0,0,0,0))
90000.0
>>>
time.mktime((1976,9,26,0,0,0,0,0,0))-time.mktime((1976,9,25,0,0,0,0,0,0))
86400.0
>>> time.mktime((1976,9,26,0,0,0,0,0,0))
212540400.0
----------------------------------------------------------------------
Comment By: Sérgio Monteiro Basto (sergiomb)
Date: 2007-02-13 12:19
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on my FC6 same
first time
>>>
time.mktime((1976,9,26,0,0,0,0,0,0))-time.mktime((1976,9,25,0,0,0,0,0,0))
90000.0
second and third time
>>>
time.mktime((1976,9,26,0,0,0,0,0,0))-time.mktime((1976,9,25,0,0,0,0,0,0))
86400.0
>>>
time.mktime((1976,9,26,0,0,0,0,0,0))-time.mktime((1976,9,25,0,0,0,0,0,0))
86400.0
----------------------------------------------------------------------
Comment By: Sérgio Monteiro Basto (sergiomb)
Date: 2007-02-13 12:18
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here with ubuntu 5.16 with python 2.4.2
kernel-2.6.12
>>> import time
>>>
time.mktime((1976,9,26,0,0,0,0,0,0))-time.mktime((1976,9,25,0,0,0,0,0,0))
90000.0
>>>
time.mktime((1976,9,26,0,0,0,0,0,0))-time.mktime((1976,9,25,0,0,0,0,0,0))
86400.0
>>>
time.mktime((1976,9,26,0,0,0,0,0,0))-time.mktime((1976,9,25,0,0,0,0,0,0))
86400.0
----------------------------------------------------------------------
Comment By: Sérgio Monteiro Basto (sergiomb)
Date: 2007-02-13 12:06
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here with ubuntu 6.10 with python 2.4.4c1
>>> import time
>>>
time.mktime((1976,9,26,0,0,0,0,0,0))-time.mktime((1976,9,25,0,0,0,0,0,0))
90000.0
----------------------------------------------------------------------
Comment By: Martin v. Löwis (loewis)
Date: 2007-02-13 06:57
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Looks like an FC6 bug to me (either in their C library, or in their Python
port). On Debian 3.1, Python 2.4.1, I also get 86400.0. Please report this
to Redhat; I'm closing this as "works for me". If you stil think there is a
bug in Python, please point to the exact source that you think is
erroneous, and the change that should be made.
----------------------------------------------------------------------
Comment By: Sérgio Monteiro Basto (sergiomb)
Date: 2007-02-12 23:37
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python-2.4.4-1.fc6
>>> import time
>>>
time.mktime((1976,9,26,0,0,0,0,0,0))-time.mktime((1976,9,25,0,0,0,0,0,0))
90000.0
----------------------------------------------------------------------
Comment By: Martin v. Löwis (loewis)
Date: 2007-02-12 13:38
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I can't reproduce this problem. On my system (OSX), I get
>>>
time.mktime((1976,9,26,0,0,0,0,0,0))-time.mktime((1976,9,25,0,0,0,0,0,0))
86400.0
What system are you using? What Python version? What timezone are you in?
----------------------------------------------------------------------
Comment By: Georg Brandl (gbrandl)
Date: 2007-02-10 16:06
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This appears to be a timezone/DST issue:
on Sept. 26, 1976 Daylight Saving Time ended at least in the European
Union.
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