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Fix Timestamp.from_datetime returning wrong value for pre-epoch datetimes #662

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Fix Timestamp.from_datetime returning wrong value for pre-epoch datetimes #662

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Fix Timestamp.from_datetime returning wrong value for pre-epoch times 
int() truncates towards zero, so for pre-epoch datetimes with non-zero
microseconds the seconds component gets the wrong value. For example,
datetime(1969, 12, 31, 23, 59, 59, 500000, UTC) has timestamp -0.5,
but int(-0.5) == 0, producing Timestamp(0, 500000000) (+0.5s after
epoch) instead of Timestamp(-1, 500000000) (-0.5s before epoch).

Use floor division (// 1) instead, consistent with from_unix().
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bysiber committed Feb 20, 2026
commit 4ea42eba4d73ff448fd81edf438e38d33d00db57
2 changes: 1 addition & 1 deletion msgpack/ext.py
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Expand Up @@ -167,4 +167,4 @@ def from_datetime(dt):

:rtype: Timestamp
"""
return Timestamp(seconds=int(dt.timestamp()), nanoseconds=dt.microsecond * 1000)
return Timestamp(seconds=int(dt.timestamp() // 1), nanoseconds=dt.microsecond * 1000)
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@methane methane Apr 21, 2026

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@copilot apply changes based on this feedback