[issue9169] Deprecate use of more than 3 positional arguments in timedelta constructor

[Alexander Belopolsky]

Alexander Belopolsky <belopolsky at users.sourceforge.net> added the comment:

> As a matter of good style, though, I'd still like to see all uses of
> timedelta in the standard library and documentation use the keywords
> explicitly ...

It is a bit of a shame, but there are exactly 3 places using timedelta in stdlib:

Lib/_strptime.py:492:        tzdelta = datetime_timedelta(seconds=gmtoff)
Lib/calendar.py:160:        date -= datetime.timedelta(days=days)
Lib/calendar.py:161:        oneday = datetime.timedelta(days=1)


The later two uses of keywords I don't necessarily approve, particularly timedelta(days=days).  I find timedelta(n) meaning n days fairly easy to remember.  Two arguments, timedelta(days, secs) is borderline.  I would approve it if the meaning is clear from context as in

MINUTE = timedelta(0, 60)

or from the the argument name as in timedelta(0, seconds).

I would certainly reject the abominations like

FIVE_MINUTES =  datetime.timedelta(0, 0, 0, 0, 5)

in any code review.

I checked datetime.rst and it looks like it only uses positional arguments for timedelta(0), which is pretty uncontroversial and in output displays.

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status: pending -> open

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<http://bugs.python.org/issue9169>
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