fix(models): use consistent naive_utc_now for created_at/updated_at, not DB server time

[iruzen-dono]

The Bug

On MySQL, func.current_timestamp() returns the database server's local time (e.g., CST = UTC+8), while the service code updates updated_at with naive_utc_now() (Python UTC). Since MySQL's DATETIME type does not store timezone info, created_at and updated_at end up with different timezone offsets — typically an 8-hour discrepancy for users in CST.

The Fix

Switch Conversation and Message models from DB-side server_default=func.current_timestamp() / onupdate=func.current_timestamp() to Python-side default=naive_utc_now / onupdate=naive_utc_now.

This ensures both created_at and updated_at always get UTC values, regardless of the database server's timezone.

Changes

• api/models/model.py: import naive_utc_now from libs.datetime_utils and replace func.current_timestamp() references with naive_utc_now

Affected columns

Model	Column	Before	After
Conversation	created_at	server_default=func.current_timestamp()	default=naive_utc_now
Conversation	updated_at	server_default=func.current_timestamp(), onupdate=func.current_timestamp()	default=naive_utc_now, onupdate=naive_utc_now
Message	created_at	server_default=func.current_timestamp()	default=naive_utc_now
Message	updated_at	server_default=func.current_timestamp(), onupdate=func.current_timestamp()	default=naive_utc_now, onupdate=naive_utc_now

References

Closes #38553

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[iruzen-dono]

Hi maintainers 👋 this PR fixes a consistency issue where model created_at/updated_at used DB server time instead of naive_utc_now, which causes timestamp drift when the DB runs in a different timezone. The fix is minimal (+7/-6). Would appreciate a review when possible.

[crazywoola]

Hi @iruzen-dono, thanks for opening this pull request.

Why this is being closed

Issue #38553 has multiple open pull requests. Under the duplicate-PR rule, pull requests from the issue author are ranked first, then creation time is used as the FIFO tie-breaker. PR #38554 is the retained pull request, so this one is being closed.

Next steps

Please coordinate on PR #38554 if you would like to contribute further. Thank you for understanding.