BUG (CoW): fix reference tracking in replace_list with None (#59807)

pandas-dev · Sep 15, 2024 · 3e8ac12 · 3e8ac12
1 parent 235e1be
commit 3e8ac12
Show file tree

Hide file tree

Showing 2 changed files with 7 additions and 1 deletion.
diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
@@ -915,7 +915,7 @@ def _replace_coerce(
                         nb = nb.copy()
                     putmask_inplace(nb.values, mask, value)
                     return [nb]
-                return [self]
+                return [self.copy(deep=False)]
             return self.replace(
                 to_replace=to_replace,
                 value=value,

diff --git a/pandas/tests/copy_view/test_replace.py b/pandas/tests/copy_view/test_replace.py
@@ -286,6 +286,12 @@ def test_replace_list_none():
 
     assert not np.shares_memory(get_array(df, "a"), get_array(df2, "a"))
 
+    # replace multiple values that don't actually replace anything with None
+    # https://github.com/pandas-dev/pandas/issues/59770
+    df3 = df.replace(["d", "e", "f"], value=None)
+    tm.assert_frame_equal(df3, df_orig)
+    assert tm.shares_memory(get_array(df, "a"), get_array(df3, "a"))
+
 
 def test_replace_list_none_inplace_refs():
     df = DataFrame({"a": ["a", "b", "c"]})