test_localtime_daylight_false_dst_true raises OverflowError: mktime argument out of range

[tpn]

BPO	15750
Nosy	@malemburg, @warsaw, @abalkin, @vstinner, @tpn, @bitdancer
Superseder	bpo-35317: test_email: test_localtime_daylight_false_dst_true() fails depending on the timezone

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2014-06-29.16:07:03.876>
created_at = <Date 2012-08-21.05:15:23.151>
labels = ['type-bug', 'tests', 'expert-email']
title = 'test_localtime_daylight_false_dst_true raises OverflowError: mktime argument out of range'
updated_at = <Date 2018-11-26.15:49:11.334>
user = 'https://github.com/tpn'

bugs.python.org fields:

activity = <Date 2018-11-26.15:49:11.334>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2014-06-29.16:07:03.876>
closer = 'vstinner'
components = ['Tests', 'email']
creation = <Date 2012-08-21.05:15:23.151>
creator = 'trent'
dependencies = []
files = []
hgrepos = []
issue_num = 15750
keywords = []
message_count = 10.0
messages = ['168741', '168743', '168747', '168755', '168760', '168836', '168839', '221856', '221857', '330442']
nosy_count = 7.0
nosy_names = ['lemburg', 'barry', 'belopolsky', 'vstinner', 'trent', 'r.david.murray', 'BreamoreBoy']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = 'needs patch'
status = 'closed'
superseder = '35317'
type = 'behavior'
url = 'https://bugs.python.org/issue15750'
versions = ['Python 3.4', 'Python 3.5']

[tpn]

On the FreeBSD 8.2 build slave:

======================================================================
ERROR: test_localtime_daylight_false_dst_true (test_utils.LocaltimeTests)
----------------------------------------------------------------------

Traceback (most recent call last):
  File "/home/buildslave/python/3.x.snakebite-freebsd82-amd64/build/Lib/test/test_email/test_utils.py", line 86, in test_localtime_daylight_false_dst_true
    t1 = utils.localtime(t0, isdst=1)
  File "/home/buildslave/python/3.x.snakebite-freebsd82-amd64/build/Lib/email/utils.py", line 397, in localtime
    seconds = time.mktime(tm)
OverflowError: mktime argument out of range

======================================================================
ERROR: test_localtime_daylight_true_dst_true (test_utils.LocaltimeTests)
----------------------------------------------------------------------

Traceback (most recent call last):
  File "/home/buildslave/python/3.x.snakebite-freebsd82-amd64/build/Lib/test/test_email/test_utils.py", line 79, in test_localtime_daylight_true_dst_true
    t1 = utils.localtime(t0, isdst=1)
  File "/home/buildslave/python/3.x.snakebite-freebsd82-amd64/build/Lib/email/utils.py", line 397, in localtime
    seconds = time.mktime(tm)
OverflowError: mktime argument out of range

---

Placeholder issue, haven't looked into it in detail yet.

[tpn]

Narrowed it down to the following snippet:

>>> time.mktime((2012, 3, 12, 1, 1, 0, 0, 72, -1))
1331514060.0
[70780 refs]
>>> time.mktime((2012, 3, 12, 1, 1, 0, 0, 72, 1))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OverflowError: mktime argument out of range
[70832 refs]

On all my FreeBSD boxes, that latter invocation always raises an OverflowError.

[tpn]

All my servers are set to use UTC, which affects how FreeBSD (and other BSDs) treat the isdst param in struct tm in mktime:

#include <stdio.h>
#include <string.h>
#include <time.h>

int main(int argc, char **argv)
{
    struct tm tm1, tm2;
    time_t t1, t2;

memset((void *)&tm1, 0, sizeof(struct tm));
memset((void *)&tm2, 0, sizeof(struct tm));

// UTC
setenv("TZ", "UTC", 1);
tzset();

    tm1.tm_sec = 0;
    tm1.tm_min = 1;
    tm1.tm_hour = 1;
    tm1.tm_mday = 12;
    tm1.tm_mon = 3;
    tm1.tm_year = 2012;
    tm1.tm_wday = -1;
    tm1.tm_yday = -1;
    tm1.tm_isdst = 1;

    t1 = mktime(&tm1);
    printf("t1 (UTC): %d\n", t1);

// EST
setenv("TZ", "CET", 1);
tzset();
tm2.tm_sec = 0;
tm2.tm_min = 1;
tm2.tm_hour = 1;
tm2.tm_mday = 12;
tm2.tm_mon = 3;
tm2.tm_year = 2012;

tm2.tm_wday = -1;
tm2.tm_yday = -1;
tm2.tm_isdst = 1;

    t2 = mktime(&tm2);
    printf("t2 (CET): %d\n", t2);

    return 0;
}

% gcc -g test_mktime.c -o test_time && ./test_time
t1 (UTC): -1
t2 (CET): 1162787116

The two tests causing problems are Lib/test/test_email/test_utils.py:

    def test_localtime_daylight_false_dst_false(self):
        test.support.patch(self, time, 'daylight', False)
        t0 = datetime.datetime(2012, 3, 12, 1, 1)
        t1 = utils.localtime(t0, isdst=-1)
        t2 = utils.localtime(t1)
        self.assertEqual(t1, t2)

    def test_localtime_daylight_true_dst_true(self):
        test.support.patch(self, time, 'daylight', True)
        t0 = datetime.datetime(2012, 3, 12, 1, 1)
        t1 = utils.localtime(t0, isdst=1)
        t2 = utils.localtime(t1)
        self.assertEqual(t1, t2)

In order for those tests to work on a *BSD server with a TZ set to UTC, TZ is going to need to be set to something else first, and then tzset() called. Otherwise, mktime() will return -1, which triggers the overflow error.

[vstinner]

email.utils.localtime() may reuse the new datetime.datetime.timestamp() method, except that this method doesn't support setting isdst (it is set to -1).

[bitdancer]

This is 3.3 only, as those tests and the function they test were only introduced in 3.3.

[bitdancer]

So you are saying that if the current timezone is UTC, FreeBSD's mktime just arbitrarily returns -1 for any time passed to it with the 'guess the DST flag' value set for is_dst? And for is_dst set to 1 as well? This isn't mentioned on the FreeBSD man page for mktime, as far as I can see.

If this is the real problem, we can fix it with the support.run_with_tz decorator, but...compiling and running your program on my linux box, I get -1 in both prints.

[abalkin]

So you are saying that if the current timezone is UTC, FreeBSD's mktime
just arbitrarily returns -1 for any time passed to it with the 'guess
the DST flag' value set for is_dst?

I don't know about FreeBSD, but I recall seeing a comment in mxDT sources that some systems only allow isdst flag of -1 in mktime.

Adding Marc-Andre.

[BreamoreBoy]

Are these tests still failing, can this issue be closed as "out of date" or what?

[vstinner]

I don't see the issue anymore, I guess that it was fixed.

[vstinner]

I mark this issue as a duplicate of bpo-35317.