[Python-checkins] cpython (3.5): Issue #28253: Fixed calendar functions for extreme months: 0001-01 and 9999-12.

Tue Sep 27 20:29:21 EDT 2016

https://hg.python.org/cpython/rev/c439bce36bf2
changeset: 104115:c439bce36bf2
branch: 3.5
parent: 104112:09cc43df4509
user: Alexander Belopolsky <alexander.belopolsky at gmail.com>
date: Tue Sep 27 20:26:39 2016 -0400
summary:
 Issue #28253: Fixed calendar functions for extreme months: 0001-01 and 9999-12.
Methods itermonthdays() and itermonthdays2() are reimplemented so that they
don't call itermonthdates() which can cause datetime.date under/overflow.
files:
 Lib/calendar.py | 19 +++++++++----------
 Lib/test/test_calendar.py | 21 +++++++++++++++++++++
 2 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/Lib/calendar.py b/Lib/calendar.py
--- a/Lib/calendar.py
+++ b/Lib/calendar.py
@@ -8,6 +8,7 @@
 import sys
 import datetime
 import locale as _locale
+from itertools import repeat
 
 __all__ = ["IllegalMonthError", "IllegalWeekdayError", "setfirstweekday",
 "firstweekday", "isleap", "leapdays", "weekday", "monthrange",
@@ -174,22 +175,20 @@
 Like itermonthdates(), but will yield (day number, weekday number)
 tuples. For days outside the specified month the day number is 0.
 """
- for date in self.itermonthdates(year, month):
- if date.month != month:
- yield (0, date.weekday())
- else:
- yield (date.day, date.weekday())
+ for i, d in enumerate(self.itermonthdays(year, month), self.firstweekday):
+ yield d, i % 7
 
 def itermonthdays(self, year, month):
 """
 Like itermonthdates(), but will yield day numbers. For days outside
 the specified month the day number is 0.
 """
- for date in self.itermonthdates(year, month):
- if date.month != month:
- yield 0
- else:
- yield date.day
+ day1, ndays = monthrange(year, month)
+ days_before = (day1 - self.firstweekday) % 7
+ yield from repeat(0, days_before)
+ yield from range(1, ndays + 1)
+ days_after = (self.firstweekday - day1 - ndays) % 7
+ yield from repeat(0, days_after)
 
 def monthdatescalendar(self, year, month):
 """
diff --git a/Lib/test/test_calendar.py b/Lib/test/test_calendar.py
--- a/Lib/test/test_calendar.py
+++ b/Lib/test/test_calendar.py
@@ -502,6 +502,27 @@
 # see #15421
 list(calendar.Calendar().itermonthdates(datetime.MAXYEAR, 12))
 
+ def test_itermonthdays(self):
+ for firstweekday in range(7):
+ cal = calendar.Calendar(firstweekday)
+ # Test the extremes, see #28253 and #26650
+ for y, m in [(1, 1), (9999, 12)]:
+ days = list(cal.itermonthdays(y, m))
+ self.assertIn(len(days), (35, 42))
+ # Test a short month
+ cal = calendar.Calendar(firstweekday=3)
+ days = list(cal.itermonthdays(2001, 2))
+ self.assertEqual(days, list(range(1, 29)))
+
+ def test_itermonthdays2(self):
+ for firstweekday in range(7):
+ cal = calendar.Calendar(firstweekday)
+ # Test the extremes, see #28253 and #26650
+ for y, m in [(1, 1), (9999, 12)]:
+ days = list(cal.itermonthdays2(y, m))
+ self.assertEqual(days[0][1], firstweekday)
+ self.assertEqual(days[-1][1], (firstweekday - 1) % 7)
+
 
 class MonthCalendarTestCase(unittest.TestCase):
 def setUp(self):
-- 
Repository URL: https://hg.python.org/cpython
