fix near-minimum timestamp overflow when scaling from microseconds to…

… nanoseconds

doc/source/whatsnew/v2.2.1.rst

@@ -15,6 +15,7 @@ Fixed regressions
 ~~~~~~~~~~~~~~~~~
 - Fixed memory leak in :func:`read_csv` (:issue:`57039`)
 - Fixed performance regression in :meth:`Series.combine_first` (:issue:`55845`)
+- Fixed regression causing overflow for near-minimum timestamps (:issue:`57150`)
 - Fixed regression in :func:`concat` changing long-standing behavior that always sorted the non-concatenation axis when the axis was a :class:`DatetimeIndex` (:issue:`57006`)
 - Fixed regression in :func:`merge_ordered` raising ``TypeError`` for ``fill_method="ffill"`` and ``how="left"`` (:issue:`57010`)
 - Fixed regression in :func:`pandas.testing.assert_series_equal` defaulting to ``check_exact=True`` when checking the :class:`Index` (:issue:`57067`)

pandas/_libs/src/vendored/numpy/datetime/np_datetime.c

@@ -481,6 +481,17 @@ npy_datetime npy_datetimestruct_to_datetime(NPY_DATETIMEUNIT base,
  }
 
  if (base == NPY_FR_ns) {
+ // for near-minimum timestamps, scaling microseconds to nanoseconds
+ // overflows but adding nanoseconds puts the timestamp back in a valid range
+ const int64_t min_nanoseconds = NPY_MIN_INT64 + 1;
+ if (microseconds == min_nanoseconds / 1000 - 1) {
+ // calculate final nanoseconds from minimum without scaling microseconds
+ int64_t nanoseconds = min_nanoseconds;
+ PD_CHECK_OVERFLOW(checked_int64_add(
+ nanoseconds, (dts->ps - _NS_MIN_DTS.ps) / 1000, &nanoseconds));
+ return nanoseconds;
+ }
+
  int64_t nanoseconds;
  PD_CHECK_OVERFLOW(
  scaleMicrosecondsToNanoseconds(microseconds, &nanoseconds));