Merge pull request #21 from snapiri/croniter_range_infinite_loop

Fix croniter_range infinite loop

2 files changed, 20 insertions, 2 deletions

diff --git a/src/croniter/croniter.py b/src/croniter/croniter.py
index 16d784f..1e4b199 100644
--- a/src/croniter/croniter.py
+++ b/src/croniter/croniter.py
@@ -279,8 +279,12 @@ class croniter(object):
                 or (lag < 0 and
                     ((3600 * abs(lag_hours) + abs(lag)) >= hours_before_midnight * 3600))
             ):
-                dtresult = dtresult - datetime.timedelta(seconds=lag)
-                result = self._datetime_to_timestamp(dtresult)
+                dtresult_adjusted = dtresult - datetime.timedelta(seconds=lag)
+                result_adjusted = self._datetime_to_timestamp(dtresult_adjusted)
+                # Do the actual adjust only if the result time actually exists
+                if self._timestamp_to_datetime(result_adjusted).tzinfo == dtresult_adjusted.tzinfo:
+                    dtresult = dtresult_adjusted
+                    result = result_adjusted
                 self.dst_start_time = result
         self.cur = result
         if issubclass(ret_type, datetime.datetime):
diff --git a/src/croniter/tests/test_croniter_range.py b/src/croniter/tests/test_croniter_range.py
index 29fc0d0..e57e4e0 100755
--- a/src/croniter/tests/test_croniter_range.py
+++ b/src/croniter/tests/test_croniter_range.py
@@ -160,6 +160,20 @@ class CroniterRangeTest(base.TestCase):
         except CroniterBadTypeRangeError:
             self.fail('should not be triggered')
 
+    def test_dst_iter(self):
+        tz = pytz.timezone('Asia/Hebron')
+        now = datetime(2022, 3, 26, 0, 0, 0, tzinfo=tz)
+        it = croniter('0 0 * * *', now)
+        ret = [
+            it.get_next(datetime).isoformat(),
+            it.get_next(datetime).isoformat(),
+            it.get_next(datetime).isoformat(),
+        ]
+        self.assertEqual(ret, [
+            '2022-03-26T00:00:00+02:00',
+            '2022-03-27T01:00:00+03:00',
+            '2022-03-28T00:00:00+03:00'])
+
 
 if __name__ == '__main__':
     unittest.main()