Add support for timestamps with timezone#649
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sfc-gh-jcieslak merged 4 commits intomainfrom Feb 25, 2026
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# Conflicts: # DESCRIPTION.md
tests/test_timestamp.py
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| def test_custom_datetime_preserves_timezone_flag(self): | ||
| custom_datetime = DateTime(timezone=True).adapt(_CUSTOM_DateTime) | ||
| assert getattr(custom_datetime, "timezone", None) is True |
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The dialect's colspecs maps DateTime -> _CUSTOM_DateTime:
snowdialect.py:60-65
colspecs = {
Date: _CUSTOM_Date,
DateTime: _CUSTOM_DateTime,
Time: _CUSTOM_Time,
Float: _CUSTOM_Float,
}When SQLAlchemy adapts DateTime(timezone=True) to _CUSTOM_DateTime, it calls .adapt(_CUSTOM_DateTime). The test test_custom_datetime_preserves_timezone_flag checks this, but _CUSTOM_DateTime inherits from both SnowflakeType and sqltypes.DateTime — it does not define __init__ to accept/forward the timezone keyword. The base DateTime.__init__ sets self.timezone, so .adapt() copies it via __dict__. It would be safer and more explicit if _CUSTOM_DateTime accepted timezone in its constructor:
class _CUSTOM_DateTime(SnowflakeType, sqltypes.DateTime):
def __init__(self, timezone=False):
super().__init__(timezone=timezone)
...This makes the intent explicit and protects against future SQLAlchemy changes to the adapt mechanism.
sfc-gh-mraba
approved these changes
Feb 25, 2026
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What GitHub issue is this PR addressing? Make sure that there is an accompanying issue to your PR.
Fixes SNOW-219884: Pandas datetime with timezone converts to
timestamp_ntzin snowflake #199Fill out the following pre-review checklist:
Please describe how your code solves the related issue.
Previously, the dialect didn't respect the timezone settings on datetime and timezone SQLAlchemy types and produced timestamp types without a timezone. With the provided change, whenever the timezone option is set for either type, the timestamp with timezone will be used.