[Bug]: datetime.strptime is broken

Describe the bug

Initially, I was thinking that this bug is related to https://github.com/oracle/graalpython/issues/532

But I think it is not. I tested it with the timezone "Europe/Berlin/ which has DST, but the result is the same.

The following code produces the following output

from java.time import ZoneId
from datetime import datetime

print("User Timezone (from -Duser.timezone) " + ZoneId.systemDefault().getId())
start_time = datetime.strptime("2025-09-26 10:00:00", "%Y-%m-%d %H:%M:%S")
print("User Timezone (from -Duser.timezone) " + ZoneId.systemDefault().getId())

2026-07-13 08:59:02.542 [INFO ] [nhab.automation.pythonscripting.test] - User Timezone (from -Duser.timezone) Europe/Berlin
2026-07-13 08:59:02.723 [INFO ] [nhab.automation.pythonscripting.test] - User Timezone (from -Duser.timezone) Etc/UTC

Any subsequent call to the timezone returns only UTC.

I tested this using GraalPy 25.0.1.

Operating system

Linux

CPU architecture

x86_64

GraalPy version

25.0.1

JDK version

No response

Context configuration

No response

Steps to reproduce

from java.time import ZoneId
from datetime import datetime

print("User Timezone (from -Duser.timezone) " + ZoneId.systemDefault().getId())
start_time = datetime.strptime("2025-09-26 10:00:00", "%Y-%m-%d %H:%M:%S")
print("User Timezone (from -Duser.timezone) " + ZoneId.systemDefault().getId())

2026-07-13 08:59:02.542 [INFO ] [nhab.automation.pythonscripting.test] - User Timezone (from -Duser.timezone) Europe/Berlin
2026-07-13 08:59:02.723 [INFO ] [nhab.automation.pythonscripting.test] - User Timezone (from -Duser.timezone) Etc/UTC

Expected behavior

don't change the system timezone

Stack trace

Additional context

No response