fold value behaves differently for different timedelta addition values

[Mcklmo]

• I am on the latest Pendulum version.
• I have searched the issues of this repo and believe that this is not a duplicate.

• OS version and name: Windows 11
• Pendulum version: 3.0.0

Issue

The fold attribute behaves weirdly when adding different timedeltas to a datetime object. Adding minutes changes the fold from 0 to 1. Adding days keeps it at 1.

On the other hand, when setting fold to 0, adding minutes preserves it, and adding days changes it.

It seems like adding minutes forces the fold attribute to be 0 and days forces it to be 1.

import pendulum

year, month, day = 2024, 5, 1
dt = pendulum.datetime(year, month, day, tz="CET")

print(dt.fold)
print(dt.add(minutes=1).fold)
print(dt.add(days=1).fold)

"""Output:
1
0
1
"""


dt = pendulum.datetime(year, month, day, tz="CET").replace(fold=0)

print(dt.fold)
print(dt.add(minutes=1).fold)
print(dt.add(days=1).fold)

"""Output:
0
0
1
"""

[jakobdo]

I have a similar issue.

When working with pendulum and dst, I ran into this issue:

str(pendulum.parse("2024-10-27 02:00:00", tz="Europe/Copenhagen"))
'2024-10-27 02:00:00+01:00'
str(pendulum.parse("2024-10-27 02:00:00", tz="Europe/Copenhagen").subtract(minutes=15))
'2024-10-27 02:45:00+02:00' <-- Why does this end as 02:00 ?
If "2024-10-27 02:00:00" = '2024-10-27 02:00:00+01:00'
I would expect
str(pendulum.parse("2024-10-27 02:00:00", tz="Europe/Copenhagen").subtract(minutes=15)) to be equal = '2024-10-27 01:45:00+01:00'

I can get the expected value using:
str(pendulum.parse("2024-10-27 02:00:00", tz="Europe/Copenhagen").replace(fold=0).subtract(minutes=15))
'2024-10-27 01:45:00+02:00'

But I seems like a "stupid" hack.