BUG: DataFrame(dt64data, dtype=td64) corner cases by jbrockmendel · Pull Request #38792 · pandas-dev/pandas (original) (raw)

what is the user facing change?

dt = np.datetime64(4, "ns")
dtype = np.dtype("m8[ns]")

pd.DataFrame({"A": [dt, dt]}, dtype=dtype)  # <-- fails to raise on master (though it doesn't cast to td64, so maybe OK?)

from datetime import datetime

scalar = datetime(9999, 1, 1)
pd.DataFrame(scalar, index=[0], columns=[0])  # <-- raises OutOfBoundsDatetime on master