Float conversion makes fillna lossy #24537
Description
For int64 data near the int64 implementation bounds, astype('float64') or ensure_float64 is lossy. The motivating case is PeriodArray.fillna
dti = pd.date_range(pd.Timestamp.max - pd.Timedelta(nanoseconds=10), periods=5, freq='ns') pi = dti.to_period('ns') parr = pi._data parr[2] = pd.NaT >>> parr.fillna(method='pad') <PeriodArray> ['NaT', 'NaT', 'NaT', 'NaT', 'NaT'] Length: 5, dtype: period[N]