Fix CoW mode not to break groupby.

Author: ueshin

python/pyspark/pandas/indexing.py

@@ -587,6 +587,16 @@ def __setitem__(self, key: Any, value: Any) -> None:
         from pyspark.pandas.series import Series, first_series
 
         if self._is_series:
+            if LooseVersion(pd.__version__) >= "3.0.0":
+                # pandas 3 CoW: mutating a Series view should not mutate the parent DataFrame.
+                self._psdf_or_psser._update_anchor(
+                    DataFrame(
+                        self._psdf_or_psser._psdf._internal.select_column(
+                            self._psdf_or_psser._column_label
+                        )
+                    )
+                )
+
             if (
                 isinstance(key, Series)
                 and (isinstance(self, iLocIndexer) or not same_anchor(key, self._psdf_or_psser))
@@ -811,7 +821,11 @@ def __setitem__(self, key: Any, value: Any) -> None:
             internal = self._internal.with_new_columns(
                 new_data_spark_columns, column_labels=column_labels, data_fields=new_fields
             )
-            self._psdf_or_psser._update_internal_frame(internal, check_same_anchor=False)
+            self._psdf_or_psser._update_internal_frame(
+                internal,
+                check_same_anchor=False,
+                anchor_force_disconnect=LooseVersion(pd.__version__) >= "3.0.0",
+            )
 
 
 class LocIndexer(LocIndexerLike):

python/pyspark/pandas/series.py

@@ -430,10 +430,7 @@ def __init__(  # type: ignore[no-untyped-def]
             assert not copy
             assert fastpath is no_default
 
-            if LooseVersion(pd.__version__) < "3.0.0":
-                self._anchor = data
-            else:
-                self._anchor = DataFrame(data)
+            self._anchor = data
             self._col_label = index
 
         elif isinstance(data, Series):