[backport 2.3.x] CoW: disable chained assignment detection for Python 3.14 (#62324)

.github/workflows/unit-tests.yml

@@ -406,5 +406,3 @@ jobs:
 
       - name: Run Tests
         uses: ./.github/actions/run-tests
-        # TEMP allow this to fail until we fixed all test failures (related to chained assignment warnings)
-        continue-on-error: true

pandas/_testing/contexts.py

@@ -13,7 +13,10 @@
 
 from pandas._config import using_copy_on_write
 
-from pandas.compat import PYPY
+from pandas.compat import (
+    PYPY,
+    WARNING_CHECK_DISABLED,
+)
 from pandas.errors import ChainedAssignmentError
 
 from pandas import set_option
@@ -204,11 +207,11 @@ def raises_chained_assignment_error(warn=True, extra_warnings=(), extra_match=()
 
         return nullcontext()
 
-    if PYPY and not extra_warnings:
+    if (PYPY or WARNING_CHECK_DISABLED) and not extra_warnings:
         from contextlib import nullcontext
 
         return nullcontext()
-    elif PYPY and extra_warnings:
+    elif (PYPY or WARNING_CHECK_DISABLED) and extra_warnings:
         return assert_produces_warning(
             extra_warnings,
             match="|".join(extra_match),
@@ -247,7 +250,7 @@ def assert_cow_warning(warn=True, match=None, **kwargs):
     """
     from pandas._testing import assert_produces_warning
 
-    if not warn:
+    if not warn or WARNING_CHECK_DISABLED:
         from contextlib import nullcontext
 
         return nullcontext()

pandas/compat/__init__.py

@@ -22,6 +22,7 @@
     PY312,
     PY314,
     PYPY,
+    WARNING_CHECK_DISABLED,
 )
 import pandas.compat.compressors
 from pandas.compat.numpy import is_numpy_dev
@@ -208,4 +209,5 @@ def get_bz2_file() -> type[pandas.compat.compressors.BZ2File]:
     "PY312",
     "PY314",
     "PYPY",
+    "WARNING_CHECK_DISABLED",
 ]

pandas/compat/_constants.py

@@ -20,6 +20,8 @@
 PYPY = platform.python_implementation() == "PyPy"
 ISMUSL = "musl" in (sysconfig.get_config_var("HOST_GNU_TYPE") or "")
 REF_COUNT = 2 if PY311 else 3
+WARNING_CHECK_DISABLED = PY314
+
 
 __all__ = [
     "IS64",

pandas/core/frame.py

@@ -54,7 +54,10 @@
 from pandas._libs.hashtable import duplicated
 from pandas._libs.lib import is_range_indexer
 from pandas.compat import PYPY
-from pandas.compat._constants import REF_COUNT
+from pandas.compat._constants import (
+    REF_COUNT,
+    WARNING_CHECK_DISABLED,
+)
 from pandas.compat._optional import import_optional_dependency
 from pandas.compat.numpy import function as nv
 from pandas.errors import (
@@ -4274,12 +4277,12 @@ def isetitem(self, loc, value) -> None:
         self._iset_item_mgr(loc, arraylike, inplace=False, refs=refs)
 
     def __setitem__(self, key, value) -> None:
-        if not PYPY and using_copy_on_write():
+        if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
             if sys.getrefcount(self) <= 3:
                 warnings.warn(
                     _chained_assignment_msg, ChainedAssignmentError, stacklevel=2
                 )
-        elif not PYPY and not using_copy_on_write():
+        elif not PYPY and not WARNING_CHECK_DISABLED and not using_copy_on_write():
             if sys.getrefcount(self) <= 3 and (
                 warn_copy_on_write()
                 or (
@@ -8983,14 +8986,19 @@ def update(
         2  3    6.0
         """
 
-        if not PYPY and using_copy_on_write():
+        if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
             if sys.getrefcount(self) <= REF_COUNT:
                 warnings.warn(
                     _chained_assignment_method_msg,
                     ChainedAssignmentError,
                     stacklevel=2,
                 )
-        elif not PYPY and not using_copy_on_write() and self._is_view_after_cow_rules():
+        elif (
+            not PYPY
+            and not WARNING_CHECK_DISABLED
+            and not using_copy_on_write()
+            and self._is_view_after_cow_rules()
+        ):
             if sys.getrefcount(self) <= REF_COUNT:
                 warnings.warn(
                     _chained_assignment_warning_method_msg,

pandas/core/generic.py

@@ -90,7 +90,10 @@
     npt,
 )
 from pandas.compat import PYPY
-from pandas.compat._constants import REF_COUNT
+from pandas.compat._constants import (
+    REF_COUNT,
+    WARNING_CHECK_DISABLED,
+)
 from pandas.compat._optional import import_optional_dependency
 from pandas.compat.numpy import function as nv
 from pandas.errors import (
@@ -7285,7 +7288,7 @@ def fillna(
         """
         inplace = validate_bool_kwarg(inplace, "inplace")
         if inplace:
-            if not PYPY and using_copy_on_write():
+            if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -7294,6 +7297,7 @@ def fillna(
                     )
             elif (
                 not PYPY
+                and not WARNING_CHECK_DISABLED
                 and not using_copy_on_write()
                 and self._is_view_after_cow_rules()
             ):
@@ -7588,7 +7592,7 @@ def ffill(
         downcast = self._deprecate_downcast(downcast, "ffill")
         inplace = validate_bool_kwarg(inplace, "inplace")
         if inplace:
-            if not PYPY and using_copy_on_write():
+            if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -7597,6 +7601,7 @@ def ffill(
                     )
             elif (
                 not PYPY
+                and not WARNING_CHECK_DISABLED
                 and not using_copy_on_write()
                 and self._is_view_after_cow_rules()
             ):
@@ -7792,7 +7797,7 @@ def bfill(
         downcast = self._deprecate_downcast(downcast, "bfill")
         inplace = validate_bool_kwarg(inplace, "inplace")
         if inplace:
-            if not PYPY and using_copy_on_write():
+            if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -7801,6 +7806,7 @@ def bfill(
                     )
             elif (
                 not PYPY
+                and not WARNING_CHECK_DISABLED
                 and not using_copy_on_write()
                 and self._is_view_after_cow_rules()
             ):
@@ -7963,7 +7969,7 @@ def replace(
 
         inplace = validate_bool_kwarg(inplace, "inplace")
         if inplace:
-            if not PYPY and using_copy_on_write():
+            if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -7972,6 +7978,7 @@ def replace(
                     )
             elif (
                 not PYPY
+                and not WARNING_CHECK_DISABLED
                 and not using_copy_on_write()
                 and self._is_view_after_cow_rules()
             ):
@@ -8415,7 +8422,7 @@ def interpolate(
         inplace = validate_bool_kwarg(inplace, "inplace")
 
         if inplace:
-            if not PYPY and using_copy_on_write():
+            if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -8424,6 +8431,7 @@ def interpolate(
                     )
             elif (
                 not PYPY
+                and not WARNING_CHECK_DISABLED
                 and not using_copy_on_write()
                 and self._is_view_after_cow_rules()
             ):
@@ -9057,7 +9065,7 @@ def clip(
         inplace = validate_bool_kwarg(inplace, "inplace")
 
         if inplace:
-            if not PYPY and using_copy_on_write():
+            if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -9066,6 +9074,7 @@ def clip(
                     )
             elif (
                 not PYPY
+                and not WARNING_CHECK_DISABLED
                 and not using_copy_on_write()
                 and self._is_view_after_cow_rules()
             ):
@@ -10975,7 +10984,7 @@ def where(
         """
         inplace = validate_bool_kwarg(inplace, "inplace")
         if inplace:
-            if not PYPY and using_copy_on_write():
+            if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -10984,6 +10993,7 @@ def where(
                     )
             elif (
                 not PYPY
+                and not WARNING_CHECK_DISABLED
                 and not using_copy_on_write()
                 and self._is_view_after_cow_rules()
             ):
@@ -11058,7 +11068,7 @@ def mask(
     ) -> Self | None:
         inplace = validate_bool_kwarg(inplace, "inplace")
         if inplace:
-            if not PYPY and using_copy_on_write():
+            if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -11067,6 +11077,7 @@ def mask(
                     )
             elif (
                 not PYPY
+                and not WARNING_CHECK_DISABLED
                 and not using_copy_on_write()
                 and self._is_view_after_cow_rules()
             ):

pandas/core/indexing.py

@@ -21,6 +21,7 @@
 from pandas._libs.indexing import NDFrameIndexerBase
 from pandas._libs.lib import item_from_zerodim
 from pandas.compat import PYPY
+from pandas.compat._constants import WARNING_CHECK_DISABLED
 from pandas.errors import (
     AbstractMethodError,
     ChainedAssignmentError,
@@ -881,12 +882,12 @@ def _ensure_listlike_indexer(self, key, axis=None, value=None) -> None:
 
     @final
     def __setitem__(self, key, value) -> None:
-        if not PYPY and using_copy_on_write():
+        if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
             if sys.getrefcount(self.obj) <= 2:
                 warnings.warn(
                     _chained_assignment_msg, ChainedAssignmentError, stacklevel=2
                 )
-        elif not PYPY and not using_copy_on_write():
+        elif not PYPY and not WARNING_CHECK_DISABLED and not using_copy_on_write():
             ctr = sys.getrefcount(self.obj)
             ref_count = 2
             if not warn_copy_on_write() and _check_cacher(self.obj):
@@ -2575,12 +2576,12 @@ def __getitem__(self, key):
         return super().__getitem__(key)
 
     def __setitem__(self, key, value) -> None:
-        if not PYPY and using_copy_on_write():
+        if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
             if sys.getrefcount(self.obj) <= 2:
                 warnings.warn(
                     _chained_assignment_msg, ChainedAssignmentError, stacklevel=2
                 )
-        elif not PYPY and not using_copy_on_write():
+        elif not PYPY and not WARNING_CHECK_DISABLED and not using_copy_on_write():
             ctr = sys.getrefcount(self.obj)
             ref_count = 2
             if not warn_copy_on_write() and _check_cacher(self.obj):
@@ -2616,12 +2617,12 @@ def _convert_key(self, key):
         return key
 
     def __setitem__(self, key, value) -> None:
-        if not PYPY and using_copy_on_write():
+        if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
             if sys.getrefcount(self.obj) <= 2:
                 warnings.warn(
                     _chained_assignment_msg, ChainedAssignmentError, stacklevel=2
                 )
-        elif not PYPY and not using_copy_on_write():
+        elif not PYPY and not WARNING_CHECK_DISABLED and not using_copy_on_write():
             ctr = sys.getrefcount(self.obj)
             ref_count = 2
             if not warn_copy_on_write() and _check_cacher(self.obj):

pandas/core/series.py

@@ -39,7 +39,10 @@
 )
 from pandas._libs.lib import is_range_indexer
 from pandas.compat import PYPY
-from pandas.compat._constants import REF_COUNT
+from pandas.compat._constants import (
+    REF_COUNT,
+    WARNING_CHECK_DISABLED,
+)
 from pandas.compat._optional import import_optional_dependency
 from pandas.compat.numpy import function as nv
 from pandas.errors import (
@@ -1269,12 +1272,12 @@ def _get_value(self, label, takeable: bool = False):
 
     def __setitem__(self, key, value) -> None:
         warn = True
-        if not PYPY and using_copy_on_write():
+        if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
             if sys.getrefcount(self) <= 3:
                 warnings.warn(
                     _chained_assignment_msg, ChainedAssignmentError, stacklevel=2
                 )
-        elif not PYPY and not using_copy_on_write():
+        elif not PYPY and not WARNING_CHECK_DISABLED and not using_copy_on_write():
             ctr = sys.getrefcount(self)
             ref_count = 3
             if not warn_copy_on_write() and _check_cacher(self):
@@ -3621,14 +3624,19 @@ def update(self, other: Series | Sequence | Mapping) -> None:
         2    3
         dtype: int64
         """
-        if not PYPY and using_copy_on_write():
+        if not PYPY and not WARNING_CHECK_DISABLED and using_copy_on_write():
             if sys.getrefcount(self) <= REF_COUNT:
                 warnings.warn(
                     _chained_assignment_method_msg,
                     ChainedAssignmentError,
                     stacklevel=2,
                 )
-        elif not PYPY and not using_copy_on_write() and self._is_view_after_cow_rules():
+        elif (
+            not PYPY
+            and not WARNING_CHECK_DISABLED
+            and not using_copy_on_write()
+            and self._is_view_after_cow_rules()
+        ):
             ctr = sys.getrefcount(self)
             ref_count = REF_COUNT
             if _check_cacher(self):

pandas/tests/copy_view/test_chained_assignment_deprecation.py

@@ -1,7 +1,10 @@
 import numpy as np
 import pytest
 
-from pandas.compat import PY311
+from pandas.compat import (
+    PY311,
+    WARNING_CHECK_DISABLED,
+)
 from pandas.errors import (
     ChainedAssignmentError,
     SettingWithCopyWarning,
@@ -150,6 +153,9 @@ def test_series_setitem(indexer, using_copy_on_write, warn_copy_on_write):
 
     # using custom check instead of tm.assert_produces_warning because that doesn't
     # fail if multiple warnings are raised
+    if WARNING_CHECK_DISABLED:
+        return
+
     with pytest.warns() as record:
         df["a"][indexer] = 0
     assert len(record) == 1