diff -r 5b2212e0c350 Lib/_strptime.py --- a/Lib/_strptime.py Sun Jan 11 12:48:17 2015 +0200 +++ b/Lib/_strptime.py Sun Jan 11 13:12:13 2015 +0200 @@ -348,9 +348,9 @@ def _strptime(data_string, format="%a %b # though week_of_year = -1 week_of_year_start = -1 - # weekday and julian defaulted to -1 so as to signal need to calculate + # weekday and julian defaulted to None so as to signal need to calculate # values - weekday = julian = -1 + weekday = julian = None found_dict = found.groupdict() for group_key in found_dict.keys(): # Directives not explicitly handled below: @@ -452,14 +452,14 @@ def _strptime(data_string, format="%a %b year = 1900 # If we know the week of the year and what day of that week, we can figure # out the Julian day of the year. - if julian == -1 and week_of_year != -1 and weekday != -1: + if julian is None and week_of_year != -1 and weekday is not None: week_starts_Mon = True if week_of_year_start == 0 else False julian = _calc_julian_from_U_or_W(year, week_of_year, weekday, week_starts_Mon) # Cannot pre-calculate datetime_date() since can change in Julian # calculation and thus could have different value for the day of the week # calculation. - if julian == -1: + if julian is None: # Need to add 1 to result since first day of the year is 1, not 0. julian = datetime_date(year, month, day).toordinal() - \ datetime_date(year, 1, 1).toordinal() + 1 @@ -469,7 +469,7 @@ def _strptime(data_string, format="%a %b year = datetime_result.year month = datetime_result.month day = datetime_result.day - if weekday == -1: + if weekday is None: weekday = datetime_date(year, month, day).weekday() # Add timezone info tzname = found_dict.get("Z") diff -r 5b2212e0c350 Lib/test/test_strptime.py --- a/Lib/test/test_strptime.py Sun Jan 11 12:48:17 2015 +0200 +++ b/Lib/test/test_strptime.py Sun Jan 11 13:12:13 2015 +0200 @@ -494,6 +494,24 @@ class CalculationTests(unittest.TestCase test_helper((2006, 12, 31), "Last Sunday of 2006") test_helper((2006, 12, 24), "Second to last Sunday of 2006") + def test_week_0(self): + def check(value, format, *expected): + self.assertEqual(_strptime._strptime_time(value, format)[:-1], expected) + check('2015 0 0', '%Y %U %w', 2014, 12, 28, 0, 0, 0, 6, -3) + check('2015 0 0', '%Y %W %w', 2015, 1, 4, 0, 0, 0, 6, 4) + check('2015 0 1', '%Y %U %w', 2014, 12, 29, 0, 0, 0, 0, -2) + check('2015 0 1', '%Y %W %w', 2014, 12, 29, 0, 0, 0, 0, -2) + check('2015 0 2', '%Y %U %w', 2014, 12, 30, 0, 0, 0, 1, -1) + check('2015 0 2', '%Y %W %w', 2014, 12, 30, 0, 0, 0, 1, -1) + check('2015 0 3', '%Y %U %w', 2014, 12, 31, 0, 0, 0, 2, 0) + check('2015 0 3', '%Y %W %w', 2014, 12, 31, 0, 0, 0, 2, 0) + check('2015 0 4', '%Y %U %w', 2015, 1, 1, 0, 0, 0, 3, 1) + check('2015 0 4', '%Y %W %w', 2015, 1, 1, 0, 0, 0, 3, 1) + check('2015 0 5', '%Y %U %w', 2015, 1, 2, 0, 0, 0, 4, 2) + check('2015 0 5', '%Y %W %w', 2015, 1, 2, 0, 0, 0, 4, 2) + check('2015 0 6', '%Y %U %w', 2015, 1, 3, 0, 0, 0, 5, 3) + check('2015 0 6', '%Y %W %w', 2015, 1, 3, 0, 0, 0, 5, 3) + class CacheTests(unittest.TestCase): """Test that caching works properly."""