STYLE start enabling TCH (#51687)

* start enabling TCH

* fixup

* fixup

---------

Co-authored-by: MarcoGorelli <>

Author: MarcoGorelli

pandas/_config/config.py

@@ -66,10 +66,8 @@
 )
 import warnings
 
-from pandas._typing import (
-    F,
-    T,
-)
+from pandas._typing import F  # noqa: TCH001
+from pandas._typing import T  # noqa: TCH001
 from pandas.util._exceptions import find_stack_level
 
 

pandas/_testing/__init__.py

@@ -25,11 +25,6 @@
     set_locale,
 )
 
-from pandas._typing import (
-    Dtype,
-    Frequency,
-    NpDtype,
-)
 from pandas.compat import pa_version_under7p0
 
 from pandas.core.dtypes.common import (
@@ -118,6 +113,12 @@
 from pandas.core.construction import extract_array
 
 if TYPE_CHECKING:
+    from pandas._typing import (
+        Dtype,
+        Frequency,
+        NpDtype,
+    )
+
     from pandas import (
         PeriodIndex,
         TimedeltaIndex,

pandas/_testing/_io.py

@@ -13,10 +13,6 @@
 )
 import zipfile
 
-from pandas._typing import (
-    FilePath,
-    ReadPickleBuffer,
-)
 from pandas.compat import get_lzma_file
 from pandas.compat._optional import import_optional_dependency
 
@@ -27,6 +23,11 @@
 from pandas.io.common import urlopen
 
 if TYPE_CHECKING:
+    from pandas._typing import (
+        FilePath,
+        ReadPickleBuffer,
+    )
+
     from pandas import (
         DataFrame,
         Series,

pandas/_testing/_random.py

@@ -1,9 +1,12 @@
+from __future__ import annotations
+
 import string
+from typing import TYPE_CHECKING
 
 import numpy as np
 
-from pandas._typing import NpDtype
-
+if TYPE_CHECKING:
+    from pandas._typing import NpDtype
 RANDS_CHARS = np.array(list(string.ascii_letters + string.digits), dtype=(np.str_, 1))
 
 

pandas/_testing/compat.py

@@ -1,10 +1,15 @@
 """
 Helpers for sharing tests between DataFrame/Series
 """
-from pandas._typing import DtypeObj
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
 
 from pandas import DataFrame
 
+if TYPE_CHECKING:
+    from pandas._typing import DtypeObj
+
 
 def get_dtype(obj) -> DtypeObj:
     if isinstance(obj, DataFrame):

pandas/_testing/contexts.py

@@ -6,23 +6,26 @@
 import tempfile
 from typing import (
     IO,
+    TYPE_CHECKING,
     Any,
     Generator,
 )
 import uuid
 
-from pandas._typing import (
-    BaseBuffer,
-    CompressionOptions,
-    FilePath,
-)
 from pandas.compat import PYPY
 from pandas.errors import ChainedAssignmentError
 
 from pandas import set_option
 
 from pandas.io.common import get_handle
 
+if TYPE_CHECKING:
+    from pandas._typing import (
+        BaseBuffer,
+        CompressionOptions,
+        FilePath,
+    )
+
 
 @contextmanager
 def decompress_file(

pandas/compat/__init__.py

@@ -12,8 +12,8 @@
 import os
 import platform
 import sys
+from typing import TYPE_CHECKING
 
-from pandas._typing import F
 from pandas.compat._constants import (
     IS64,
     PY39,
@@ -33,6 +33,9 @@
     pa_version_under11p0,
 )
 
+if TYPE_CHECKING:
+    from pandas._typing import F
+
 
 def set_function_name(f: F, name: str, cls) -> F:
     """

pandas/compat/_optional.py

@@ -2,13 +2,16 @@
 
 import importlib
 import sys
-import types
+from typing import TYPE_CHECKING
 import warnings
 
 from pandas.util._exceptions import find_stack_level
 
 from pandas.util.version import Version
 
+if TYPE_CHECKING:
+    import types
+
 # Update install.rst & setup.cfg when updating versions!
 
 VERSIONS = {

pandas/compat/numpy/function.py

@@ -18,6 +18,7 @@
 from __future__ import annotations
 
 from typing import (
+    TYPE_CHECKING,
     Any,
     TypeVar,
     cast,
@@ -30,18 +31,20 @@
     is_bool,
     is_integer,
 )
-from pandas._typing import (
-    Axis,
-    AxisInt,
-)
 from pandas.errors import UnsupportedFunctionCall
 from pandas.util._validators import (
     validate_args,
     validate_args_and_kwargs,
     validate_kwargs,
 )
 
-AxisNoneT = TypeVar("AxisNoneT", Axis, None)
+if TYPE_CHECKING:
+    from pandas._typing import (
+        Axis,
+        AxisInt,
+    )
+
+    AxisNoneT = TypeVar("AxisNoneT", Axis, None)
 
 
 class CompatValidator:

pandas/core/_numba/executor.py

@@ -6,9 +6,11 @@
     Callable,
 )
 
+if TYPE_CHECKING:
+    from pandas._typing import Scalar
+
 import numpy as np
 
-from pandas._typing import Scalar
 from pandas.compat._optional import import_optional_dependency
 
 

pandas/core/_numba/kernels/shared.py

@@ -1,7 +1,11 @@
 from __future__ import annotations
 
+from typing import TYPE_CHECKING
+
 import numba
-import numpy as np
+
+if TYPE_CHECKING:
+    import numpy as np
 
 
 @numba.jit(

pandas/core/computation/expressions.py

@@ -8,13 +8,13 @@
 from __future__ import annotations
 
 import operator
+from typing import TYPE_CHECKING
 import warnings
 
 import numpy as np
 
 from pandas._config import get_option
 
-from pandas._typing import FuncType
 from pandas.util._exceptions import find_stack_level
 
 from pandas.core.computation.check import NUMEXPR_INSTALLED
@@ -23,6 +23,9 @@
 if NUMEXPR_INSTALLED:
     import numexpr as ne
 
+if TYPE_CHECKING:
+    from pandas._typing import FuncType
+
 _TEST_MODE: bool | None = None
 _TEST_RESULT: list[bool] = []
 USE_NUMEXPR = NUMEXPR_INSTALLED

pandas/core/computation/pytables.py

@@ -3,15 +3,17 @@
 
 import ast
 from functools import partial
-from typing import Any
+from typing import (
+    TYPE_CHECKING,
+    Any,
+)
 
 import numpy as np
 
 from pandas._libs.tslibs import (
     Timedelta,
     Timestamp,
 )
-from pandas._typing import npt
 from pandas.errors import UndefinedVariableError
 
 from pandas.core.dtypes.common import is_list_like
@@ -33,6 +35,9 @@
     pprint_thing_encoded,
 )
 
+if TYPE_CHECKING:
+    from pandas._typing import npt
+
 
 class PyTablesScope(_scope.Scope):
     __slots__ = ("queryables",)

pandas/core/indexing.py

@@ -17,10 +17,6 @@
 
 from pandas._libs.indexing import NDFrameIndexerBase
 from pandas._libs.lib import item_from_zerodim
-from pandas._typing import (
-    Axis,
-    AxisInt,
-)
 from pandas.compat import PYPY
 from pandas.errors import (
     AbstractMethodError,
@@ -79,6 +75,11 @@
 )
 
 if TYPE_CHECKING:
+    from pandas._typing import (
+        Axis,
+        AxisInt,
+    )
+
     from pandas import (
         DataFrame,
         Series,

pandas/core/interchange/utils.py

@@ -9,11 +9,12 @@
 
 import numpy as np
 
-from pandas._typing import DtypeObj
-
 import pandas as pd
 from pandas.api.types import is_datetime64_dtype
 
+if typing.TYPE_CHECKING:
+    from pandas._typing import DtypeObj
+
 
 class ArrowCTypes:
     """

pandas/core/sample.py

@@ -8,14 +8,15 @@
 import numpy as np
 
 from pandas._libs import lib
-from pandas._typing import AxisInt
 
 from pandas.core.dtypes.generic import (
     ABCDataFrame,
     ABCSeries,
 )
 
 if TYPE_CHECKING:
+    from pandas._typing import AxisInt
+
     from pandas.core.generic import NDFrame
 
 

pyproject.toml

@@ -218,6 +218,8 @@ select = [
   "TID",
   # implicit string concatenation
   "ISC",
+  # type-checking imports
+  "TCH",
 ]
 
 ignore = [
@@ -288,6 +290,42 @@ exclude = [
 [tool.ruff.per-file-ignores]
 # relative imports allowed for asv_bench
 "asv_bench/*" = ["TID"]
+# TCH to be enabled gradually
+"pandas/core/arrays/*" = ["TCH"]
+"pandas/core/io/*" = ["TCH"]
+"pandas/core/indexers/*" = ["TCH"]
+"pandas/core/indexes/*" = ["TCH"]
+"pandas/core/internals/*" = ["TCH"]
+"pandas/core/groupby/*" = ["TCH"]
+"pandas/core/methods/*" = ["TCH"]
+"pandas/core/array_algos/*" = ["TCH"]
+"pandas/core/dtypes/*" = ["TCH"]
+"pandas/core/generic.py" = ["TCH"]
+"pandas/core/frame.py" = ["TCH"]
+"pandas/core/series.py" = ["TCH"]
+"pandas/core/resample.py" = ["TCH"]
+"pandas/core/nanops.py" = ["TCH"]
+"pandas/core/apply.py" = ["TCH"]
+"pandas/core/base.py" = ["TCH"]
+"pandas/core/algorithms.py" = ["TCH"]
+"pandas/core/ops/*" = ["TCH"]
+"pandas/core/sorting.py" = ["TCH"]
+"pandas/core/construction.py" = ["TCH"]
+"pandas/core/common.py" = ["TCH"]
+"pandas/core/missing.py" = ["TCH"]
+"pandas/core/util/*" = ["TCH"]
+"pandas/core/reshape/*" = ["TCH"]
+"pandas/core/strings/*" = ["TCH"]
+"pandas/core/tools/*" = ["TCH"]
+"pandas/core/window/*" = ["TCH"]
+"pandas/io/*" = ["TCH"]
+"pandas/tseries/*" = ["TCH"]
+"pandas/tests/*" = ["TCH"]
+"pandas/plotting/*" = ["TCH"]
+"pandas/util/*" = ["TCH"]
+"pandas/_libs/*" = ["TCH"]
+# Keep this one enabled
+"pandas/_typing.py" = ["TCH"]
 
 [tool.pylint.messages_control]
 max-line-length = 88