Error when day of the month and day of the week both a specified

[naiquevin]

Came across this case where if the day of the month is also specified along with day of the week (eg. Friday the 13th), it results in a ValueError

In [59]: import crontab

In [60]: crontab.CronTab('* * 13 * Fri *')
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-60-7bef4be30389> in <module>()
----> 1 crontab.CronTab('* * 13 * Fri *')

/Library/Python/2.7/site-packages/crontab/_crontab.pyc in __init__(self, crontab)
    324     __slots__ = 'matchers',
    325     def __init__(self, crontab):
--> 326         self.matchers = self._make_matchers(crontab)
    327 
    328     def _make_matchers(self, crontab):

/Library/Python/2.7/site-packages/crontab/_crontab.pyc in _make_matchers(self, crontab)
    342         if not matchers.day.any:
    343             _assert(matchers.weekday.any,
--> 344                 "missing a wildcard specifier for weekday")
    345         if not matchers.weekday.any:
    346             _assert(matchers.day.any,

/Library/Python/2.7/site-packages/crontab/_crontab.pyc in _assert(condition, message, *args)
    164 def _assert(condition, message, *args):
    165     if not condition:
--> 166         raise ValueError(message%args)
    167 
    168 class _Matcher(object):

ValueError: missing a wildcard specifier for weekday

When day of month is not specified, it works fine

In [61]: crontab.CronTab('* * * * Fri *')
Out[61]: <crontab._crontab.CronTab at 0x103f68e50>

Not sure if this is a valid combination to use as per the cron spec as I didn't find anything mentioned about it here - https://en.wikipedia.org/wiki/Cron#CRON_expression.

[grahambell]

If both are specified, I think Cron (at least typical versions on Linux) would accept either matching, see e.g. http://manpages.ubuntu.com/manpages/xenial/man5/crontab.5.html

Note: The day of a command's execution can be specified by two fields —
day of month, and day of week. If both fields are restricted (i.e.,
aren't *), the command will be run when either field matches the
current time.

I had been meaning to look into this because a project I maintain, which uses this module, has a method for matching datetimes which I wrote before the CronTab.test method was added. I think both my method and CronTab.test would require both day specifiers to match (if you could construct the object in the first place).

[josiahcarlson]

That is a perfectly valid cron schedule. The module should accept that data, and should work correctly. One note about the example schedule; that the job would run once/minute for all 1440 minutes every Friday.

I'll work on getting this fixed and pushed. Will update this bug with more info, when it happens.

[josiahcarlson]

This is fixed in 0.21.3, which is on PyPI now.

[naiquevin]

Awesome, thanks 👍