Closed
Description
See #21427
The issue is that a (non-Day
) Tick
object with normalize=True
breaks addition monotonicity/associativity:
now = pd.Timestamp.now()
tick = pd.offsets.Minute(n=3, normalize=True)
>>> now
Timestamp('2018-06-11 17:38:10.135400')
>>> now + tick
Timestamp('2018-06-11 00:00:00')
>>> now + 64*tick + 64*tick
Timestamp('2018-06-11 00:00:00')
>>> now + 128*tick
Timestamp('2018-06-12 00:00:00')
The Day
tick doesn't have the same problem, but I'd prefer to disallow it rather than make it a double-special-case. (See #20633 for more discussion about how Day
should behave)