TST: run python-dev CI on 3.14-dev

.github/workflows/unit-tests.yml

@@ -313,7 +313,6 @@ jobs:
     #    To freeze this file, uncomment out the ``if: false`` condition, and migrate the jobs
     #    to the corresponding posix/windows-macos/sdist etc. workflows.
     # Feel free to modify this comment as necessary.
-    if: false
     defaults:
       run:
         shell: bash -eou pipefail {0}
@@ -345,7 +344,7 @@ jobs:
       - name: Set up Python Dev Version
         uses: actions/setup-python@v5
         with:
-          python-version: '3.13-dev'
+          python-version: '3.14-dev'
 
       - name: Build Environment
         run: |

pandas/_testing/contexts.py

@@ -12,7 +12,10 @@
 )
 import uuid
 
-from pandas.compat import PYPY
+from pandas.compat import (
+    PYPY,
+    WARNING_CHECK_BROKEN,
+)
 from pandas.errors import ChainedAssignmentError
 
 from pandas.io.common import get_handle
@@ -163,7 +166,7 @@ def with_csv_dialect(name: str, **kwargs) -> Generator[None]:
 def raises_chained_assignment_error(extra_warnings=(), extra_match=()):
     from pandas._testing import assert_produces_warning
 
-    if PYPY:
+    if PYPY or WARNING_CHECK_BROKEN:
         if not extra_warnings:
             from contextlib import nullcontext
 

pandas/compat/__init__.py

@@ -20,7 +20,9 @@
     ISMUSL,
     PY311,
     PY312,
+    PY314,
     PYPY,
+    WARNING_CHECK_BROKEN,
     WASM,
 )
 from pandas.compat.numpy import is_numpy_dev
@@ -157,7 +159,9 @@ def is_ci_environment() -> bool:
     "ISMUSL",
     "PY311",
     "PY312",
+    "PY314",
     "PYPY",
+    "WARNING_CHECK_BROKEN",
     "WASM",
     "is_numpy_dev",
     "pa_version_under12p1",

pandas/compat/_constants.py

@@ -15,10 +15,13 @@
 
 PY311 = sys.version_info >= (3, 11)
 PY312 = sys.version_info >= (3, 12)
+PY314 = sys.version_info >= (3, 14)
 PYPY = platform.python_implementation() == "PyPy"
 WASM = (sys.platform == "emscripten") or (platform.machine() in ["wasm32", "wasm64"])
 ISMUSL = "musl" in (sysconfig.get_config_var("HOST_GNU_TYPE") or "")
 REF_COUNT = 2 if PY311 else 3
+# hopefully there is a workaround in Python 3.14.1
+WARNING_CHECK_BROKEN = PY314
 
 __all__ = [
     "IS64",

pandas/core/frame.py

@@ -49,7 +49,10 @@
 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_BROKEN,
+)
 from pandas.compat._optional import import_optional_dependency
 from pandas.compat.numpy import function as nv
 from pandas.errors import (
@@ -4296,8 +4299,8 @@ def __setitem__(self, key, value) -> None:
         z  3  50
         # Values for 'a' and 'b' are completely ignored!
         """
-        if not PYPY:
-            if sys.getrefcount(self) <= 3:
+        if not PYPY and not WARNING_CHECK_BROKEN:
+            if sys.getrefcount(self) <= REF_COUNT + 1:
                 warnings.warn(
                     _chained_assignment_msg, ChainedAssignmentError, stacklevel=2
                 )
@@ -9204,7 +9207,7 @@ def update(
         1  2  500.0
         2  3    6.0
         """
-        if not PYPY:
+        if not PYPY and not WARNING_CHECK_BROKEN:
             if sys.getrefcount(self) <= REF_COUNT:
                 warnings.warn(
                     _chained_assignment_method_msg,

pandas/core/generic.py

@@ -83,7 +83,10 @@
     npt,
 )
 from pandas.compat import PYPY
-from pandas.compat._constants import REF_COUNT
+from pandas.compat._constants import (
+    REF_COUNT,
+    WARNING_CHECK_BROKEN,
+)
 from pandas.compat._optional import import_optional_dependency
 from pandas.compat.numpy import function as nv
 from pandas.errors import (
@@ -7069,7 +7072,7 @@ def fillna(
         """
         inplace = validate_bool_kwarg(inplace, "inplace")
         if inplace:
-            if not PYPY:
+            if not PYPY and not WARNING_CHECK_BROKEN:
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -7300,7 +7303,7 @@ def ffill(
         """
         inplace = validate_bool_kwarg(inplace, "inplace")
         if inplace:
-            if not PYPY:
+            if not PYPY and not WARNING_CHECK_BROKEN:
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -7440,7 +7443,7 @@ def bfill(
         """
         inplace = validate_bool_kwarg(inplace, "inplace")
         if inplace:
-            if not PYPY:
+            if not PYPY and not WARNING_CHECK_BROKEN:
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -7525,7 +7528,7 @@ def replace(
 
         inplace = validate_bool_kwarg(inplace, "inplace")
         if inplace:
-            if not PYPY:
+            if not PYPY and not WARNING_CHECK_BROKEN:
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -7888,7 +7891,7 @@ def interpolate(
         inplace = validate_bool_kwarg(inplace, "inplace")
 
         if inplace:
-            if not PYPY:
+            if not PYPY and not WARNING_CHECK_BROKEN:
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -8472,7 +8475,7 @@ def clip(
         inplace = validate_bool_kwarg(inplace, "inplace")
 
         if inplace:
-            if not PYPY:
+            if not PYPY and not WARNING_CHECK_BROKEN:
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -10081,7 +10084,7 @@ def where(
         """
         inplace = validate_bool_kwarg(inplace, "inplace")
         if inplace:
-            if not PYPY:
+            if not PYPY and not WARNING_CHECK_BROKEN:
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,
@@ -10145,7 +10148,7 @@ def mask(
     ) -> Self | None:
         inplace = validate_bool_kwarg(inplace, "inplace")
         if inplace:
-            if not PYPY:
+            if not PYPY and not WARNING_CHECK_BROKEN:
                 if sys.getrefcount(self) <= REF_COUNT:
                     warnings.warn(
                         _chained_assignment_method_msg,

pandas/core/indexing.py

@@ -15,6 +15,10 @@
 from pandas._libs.indexing import NDFrameIndexerBase
 from pandas._libs.lib import item_from_zerodim
 from pandas.compat import PYPY
+from pandas.compat._constants import (
+    REF_COUNT,
+    WARNING_CHECK_BROKEN,
+)
 from pandas.errors import (
     AbstractMethodError,
     ChainedAssignmentError,
@@ -913,8 +917,8 @@ def _ensure_listlike_indexer(self, key, axis=None, value=None) -> None:
 
     @final
     def __setitem__(self, key, value) -> None:
-        if not PYPY:
-            if sys.getrefcount(self.obj) <= 2:
+        if not PYPY and not WARNING_CHECK_BROKEN:
+            if sys.getrefcount(self.obj) <= REF_COUNT:
                 warnings.warn(
                     _chained_assignment_msg, ChainedAssignmentError, stacklevel=2
                 )

pandas/core/series.py

@@ -34,7 +34,10 @@
 )
 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_BROKEN,
+)
 from pandas.compat._optional import import_optional_dependency
 from pandas.compat.numpy import function as nv
 from pandas.errors import (
@@ -1059,8 +1062,8 @@ def _get_value(self, label, takeable: bool = False):
             return self.iloc[loc]
 
     def __setitem__(self, key, value) -> None:
-        if not PYPY:
-            if sys.getrefcount(self) <= 3:
+        if not PYPY and not WARNING_CHECK_BROKEN:
+            if sys.getrefcount(self) <= REF_COUNT + 1:
                 warnings.warn(
                     _chained_assignment_msg, ChainedAssignmentError, stacklevel=2
                 )
@@ -3338,7 +3341,7 @@ def update(self, other: Series | Sequence | Mapping) -> None:
         2    3
         dtype: int64
         """
-        if not PYPY:
+        if not PYPY and not WARNING_CHECK_BROKEN:
             if sys.getrefcount(self) <= REF_COUNT:
                 warnings.warn(
                     _chained_assignment_method_msg,

pandas/tests/copy_view/test_chained_assignment_deprecation.py

@@ -1,6 +1,7 @@
 import numpy as np
 import pytest
 
+from pandas.compat import WARNING_CHECK_BROKEN
 from pandas.errors import ChainedAssignmentError
 
 from pandas import DataFrame
@@ -17,6 +18,8 @@ def test_series_setitem(indexer):
 
     # using custom check instead of tm.assert_produces_warning because that doesn't
     # fail if multiple warnings are raised
+    if WARNING_CHECK_BROKEN:
+        return
     with pytest.warns() as record:  # noqa: TID251
         df["a"][indexer] = 0
     assert len(record) == 1

pandas/tests/frame/test_query_eval.py

@@ -168,7 +168,7 @@ def test_query_duplicate_column_name(self, engine, parser):
             }
         ).rename(columns={"B": "A"})
 
-        res = df.query('C == 1', engine=engine, parser=parser)
+        res = df.query("C == 1", engine=engine, parser=parser)
 
         expect = DataFrame(
             [[1, 1, 1]],
@@ -1411,7 +1411,7 @@ def test_expr_with_column_name_with_backtick_and_hash(self):
     def test_expr_with_column_name_with_backtick(self):
         # GH 59285
         df = DataFrame({"a`b": (1, 2, 3), "ab": (4, 5, 6)})
-        result = df.query("`a``b` < 2")  # noqa
+        result = df.query("`a``b` < 2")
         # Note: Formatting checks may wrongly consider the above ``inline code``.
         expected = df[df["a`b"] < 2]
         tm.assert_frame_equal(result, expected)

pandas/tests/indexes/test_indexing.py

@@ -18,6 +18,7 @@
 import numpy as np
 import pytest
 
+from pandas.compat import PY314
 from pandas.errors import InvalidIndexError
 
 from pandas.core.dtypes.common import (
@@ -160,13 +161,19 @@ def test_contains_requires_hashable_raises(self, index):
         with pytest.raises(TypeError, match=msg):
             [] in index
 
+        if PY314:
+            container_or_iterable = "a container or iterable"
+        else:
+            container_or_iterable = "iterable"
+
         msg = "|".join(
             [
                 r"unhashable type: 'dict'",
                 r"must be real number, not dict",
                 r"an integer is required",
                 r"\{\}",
-                r"pandas\._libs\.interval\.IntervalTree' is not iterable",
+                r"pandas\._libs\.interval\.IntervalTree' is not "
+                f"{container_or_iterable}",
             ]
         )
         with pytest.raises(TypeError, match=msg):

pandas/tests/io/formats/test_to_latex.py

@@ -1,4 +1,3 @@
-import codecs
 from datetime import datetime
 from textwrap import dedent
 
@@ -42,15 +41,15 @@ def test_to_latex_to_file_utf8_with_encoding(self):
         df = DataFrame([["au\xdfgangen"]])
         with tm.ensure_clean("test.tex") as path:
             df.to_latex(path, encoding="utf-8")
-            with codecs.open(path, "r", encoding="utf-8") as f:
+            with open(path, encoding="utf-8") as f:
                 assert df.to_latex() == f.read()
 
     def test_to_latex_to_file_utf8_without_encoding(self):
         # test with utf-8 without encoding option
         df = DataFrame([["au\xdfgangen"]])
         with tm.ensure_clean("test.tex") as path:
             df.to_latex(path)
-            with codecs.open(path, "r", encoding="utf-8") as f:
+            with open(path, encoding="utf-8") as f:
                 assert df.to_latex() == f.read()
 
     def test_to_latex_tabular_with_index(self):

pandas/tests/io/parser/test_quoting.py

@@ -8,7 +8,10 @@
 
 import pytest
 
-from pandas.compat import PY311
+from pandas.compat import (
+    PY311,
+    PY314,
+)
 from pandas.errors import ParserError
 
 from pandas import DataFrame
@@ -21,15 +24,24 @@
 skip_pyarrow = pytest.mark.usefixtures("pyarrow_skip")
 
 
+if PY314:
+    # TODO: write a regex that works with all new possitibilities here
+    MSG1 = ""
+    MSG2 = r"[\s\S]*"
+else:
+    MSG1 = "a(n)? 1-character string"
+    MSG2 = "string( or None)?"
+
+
 @pytest.mark.parametrize(
     "kwargs,msg",
     [
-        ({"quotechar": "foo"}, '"quotechar" must be a(n)? 1-character string'),
+        ({"quotechar": "foo"}, f'"quotechar" must be {MSG1}'),
         (
             {"quotechar": None, "quoting": csv.QUOTE_MINIMAL},
             "quotechar must be set if quoting enabled",
         ),
-        ({"quotechar": 2}, '"quotechar" must be string( or None)?, not int'),
+        ({"quotechar": 2}, f'"quotechar" must be {MSG2}, not int'),
     ],
 )
 @skip_pyarrow  # ParserError: CSV parse error: Empty CSV file or block
@@ -88,8 +100,12 @@ def test_null_quote_char(all_parsers, quoting, quote_char):
 
     if quoting != csv.QUOTE_NONE:
         # Sanity checking.
+        if not PY314:
+            msg = "1-character string"
+        else:
+            msg = "unicode character or None"
         msg = (
-            '"quotechar" must be a 1-character string'
+            f'"quotechar" must be a {msg}'
             if PY311 and all_parsers.engine == "python" and quote_char == ""
             else "quotechar must be set if quoting enabled"
         )