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call-datetime-strptime-without-zone (DTZ007)

Added in v0.0.188 · Related issues · View source

Derived from the flake8-datetimez linter.

What it does

Checks for uses of datetime.datetime.strptime() that lead to naive datetime objects.

Why is this bad?

Python datetime objects can be naive or timezone-aware. While an aware object represents a specific moment in time, a naive object does not contain enough information to unambiguously locate itself relative to other datetime objects. Since this can lead to errors, it is recommended to always use timezone-aware objects.

datetime.datetime.strptime() without %z returns a naive datetime object. Follow it with .replace(tzinfo=<timezone>) or .astimezone().

Example

import datetime

datetime.datetime.strptime("2022/01/31", "%Y/%m/%d")

Instead, use .replace(tzinfo=<timezone>):

import datetime

datetime.datetime.strptime("2022/01/31", "%Y/%m/%d").replace(
    tzinfo=datetime.timezone.utc
)

Or, use .astimezone():

import datetime

datetime.datetime.strptime("2022/01/31", "%Y/%m/%d").astimezone(datetime.timezone.utc)

On Python 3.11 and later, datetime.timezone.utc can be replaced with datetime.UTC.

References