[New-bugs-announce] [issue14267] TimedRotatingFileHandler chooses wrong file name due to daylight saving time "spring forward"

[Matt Mullins]

New submission from Matt Mullins <mokomull at gmail.com>:

As logs were rotated at midnight this morning (at the end of the day 2012-03-11), we detected that the logs were incorrectly renamed to *.log.2012-03-10, causing logs from Saturday to be overwritten.  I believe this bug is related to the transition to daylight saving time, as this is the only day in recent history that this has occurred.

I have attached a script to reproduce this bug.  This works reliably in the US/Pacific time zone.  To run it, execute "rm foo.log* ; sudo date 03112359.55 && python logger_test.py".  This will cause ten records to be logged, across the midnight boundary from 2012-03-11 23:59:55 to 2012-03-12 00:00:05.

Expected behavior: the logs from 2012-03-11 up to, but not including, 2012-03-12 00:00:00 should be written to a file named "foo.log.2012-03-11", and the remainder of the log entries should be written to "foo.log".

Actual behavior: the logs from 2012-03-11 23:59 through, but not including, 2012-03-12 00:00 are instead written to a file named "foo.log.2012-03-10", and the remainder of the log entries are written to "foo.log".

This does not happen for any other day.  For example: running "sudo date 02152359.55" in the above procedure correctly names the file "foo.log.2012-02-15".

----------
components: Library (Lib)
files: logger_test.py
messages: 155482
nosy: Matt.Mullins
priority: normal
severity: normal
status: open
title: TimedRotatingFileHandler chooses wrong file name due to daylight saving time "spring forward"
type: behavior
versions: Python 2.6, Python 2.7
Added file: http://bugs.python.org/file24799/logger_test.py

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<http://bugs.python.org/issue14267>
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