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call-datetime-today (DTZ002)

Added in v0.0.188 · Related issues · View source

Derived from the flake8-datetimez linter.

What it does

Checks for usage of datetime.datetime.today().

Why is this bad?

datetime objects are "naive" by default, in that they do not include timezone information. "Naive" objects are easy to understand, but ignore some aspects of reality, which can lead to subtle bugs. Timezone-aware datetime objects are preferred, as they represent a specific moment in time, unlike "naive" objects.

datetime.datetime.today() creates a "naive" object; instead, use datetime.datetime.now(tz=...) to create a timezone-aware object.

The name today() can be misleading, because it suggests a calendar date, but it actually returns the current local date and time as a datetime. That can make intent harder to infer when reading code.

Example

import datetime

datetime.datetime.today()

Use instead:

import datetime

datetime.datetime.now(tz=datetime.timezone.utc)

Or, for Python 3.11 and later:

import datetime

datetime.datetime.now(tz=datetime.UTC)

References