Fix pandas-dev#61208: OverflowError when fillna on DataFrame with a pd.Timestamp

- Now correctly raises OutOfBoundsDatetime
- Added test_fillna_out_of_bounds_datetime()

Author: PedroM4rques

pandas/core/internals/blocks.py

@@ -1749,6 +1749,8 @@ def putmask(self, mask, new) -> list[Block]:
         try:
             # Caller is responsible for ensuring matching lengths
             values._putmask(mask, new)
+        except OutOfBoundsDatetime as e:
+            raise
         except (TypeError, ValueError):
             if self.ndim == 1 or self.shape[0] == 1:
                 if isinstance(self.dtype, IntervalDtype):

pandas/tests/frame/methods/test_fillna.py

@@ -15,6 +15,7 @@
 )
 import pandas._testing as tm
 from pandas.tests.frame.common import _check_mixed_float
+from pandas.errors import OutOfBoundsDatetime
 
 
 class TestFillNA:
@@ -781,3 +782,19 @@ def test_fillna_with_none_object(test_frame, dtype):
     if test_frame:
         expected = expected.to_frame()
     tm.assert_equal(result, expected)
+    
+    
+def test_fillna_out_of_bounds_datetime():
+    # GH#61208
+    df = DataFrame({
+        'datetime': date_range('1/1/2011', periods=3, freq='h'),
+        'value': [1, 2, 3]
+    })
+    df.iloc[0, 0] = None
+
+    msg="Cannot cast 0001-01-01 00:00:00 to unit='ns' without overflow"
+    with pytest.raises(
+        OutOfBoundsDatetime,
+        match=msg
+    ):
+        df.fillna(Timestamp('0001-01-01'), inplace=True)