Python TypeError: can't compare offset-naive and offset-aware datetimes — the one conversion you actually need

verbatim errorTypeError: can't compare offset-naive and offset-aware datetimes File "/app/src/tasks/daily_report.py", line 41, in run if event.occurred_at >= window_start:

Problem

A daily report job crashed the first time it met a timestamp from the new "timezone-aware" column:

TypeError: can't compare offset-naive and offset-aware datetimes
  File "/app/src/tasks/daily_report.py", line 41, in run
    if event.occurred_at >= window_start:

event.occurred_at was aware (read from a timestamptz column); window_start was naive (datetime.now() — no tzinfo). Python refuses to guess which timezone the naive one means.

Root cause

Python datetime objects carry an optional tzinfo, and comparison/substraction requires both sides to agree on whether time is anchored. datetime.now() is naive local-ish time; datetime.utcnow() is naive UTC; datetime.now(timezone.utc) is aware UTC. The three are different values, and mixing any two produces either this TypeError or — worse — silently wrong windows (the naive-vs-naive case where someone mixed utcnow() with local now() and the report was off by the UTC offset forever).

fix preview — first 3 of 4 lines (python), truncated:

from datetime import datetime, timezone, timedelta

window_start = datetime.now(timezone.utc) - timedelta(hours=24)
… 1 more line in the fix

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