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.

1 files changed, 21 insertions, 0 deletions

diff --git a/Lib/test/test_calendar.py b/Lib/test/test_calendar.py
index 46c4a6f..b87b04f 100644
--- a/Lib/test/test_calendar.py
+++ b/Lib/test/test_calendar.py
@@ -291,6 +291,27 @@ class CalendarTestCase(unittest.TestCase):
         # 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):