BUG: Series.round with pd.NA no longer raises; coerce object+NA to nullable float and round; add test (#61712)

Author: CyberSully

pandas/core/series.py

@@ -2516,7 +2516,12 @@ def round(self, decimals: int = 0, *args, **kwargs) -> Series:
         """
         nv.validate_round(args, kwargs)
         if self.dtype == "object":
-            raise TypeError("Expected numeric dtype, got object instead.")
+            # Try to safely cast to numeric type (like float) if values are pd.NA or numbers
+            try:
+                converted = self.astype("Float64")
+                return converted.round(decimals)
+            except Exception:
+                raise TypeError("Expected numeric dtype, got object instead.")
         new_mgr = self._mgr.round(decimals=decimals)
         return self._constructor_from_mgr(new_mgr, axes=new_mgr.axes).__finalize__(
             self, method="round"

pandas/tests/series/methods/test_round.py

@@ -79,3 +79,11 @@ def test_round_dtype_object(self):
         msg = "Expected numeric dtype, got object instead."
         with pytest.raises(TypeError, match=msg):
             ser.round()
+
+    def test_round_with_pd_na(self):
+        import pandas as pd
+        import numpy as np
+        s = pd.Series([0.5, pd.NA], dtype="object")
+        result = s.round(0)
+        expected = pd.Series([0.0, pd.NA], dtype="Float64")
+        pd.testing.assert_series_equal(result, expected)