fix(type hints): move conditional typing imports into common.typing

ibis/common/patterns.py

@@ -10,7 +10,6 @@
 from inspect import Parameter
 from itertools import chain
 from typing import (
-    TYPE_CHECKING,
     Annotated,
     ForwardRef,
     Generic,  # noqa: F401
@@ -27,28 +26,16 @@
 from ibis.common.bases import Singleton, Slotted
 from ibis.common.collections import FrozenDict, RewindableIterator, frozendict
 from ibis.common.dispatch import lazy_singledispatch
-from ibis.common.typing import Sentinel, get_bound_typevars, get_type_params
+from ibis.common.typing import (
+    ModuleType,
+    Sentinel,
+    UnionType,
+    _ClassInfo,
+    get_bound_typevars,
+    get_type_params,
+)
 from ibis.util import is_iterable, promote_tuple
 
-if TYPE_CHECKING:
-    from types import ModuleType
-
-if sys.version_info >= (3, 10):
-    from types import UnionType
-    from typing import TypeAlias
-else:
-    from typing_extensions import TypeAlias
-
-    UnionType = object()
-
-
-# Keep this alias in sync with unittest.case._ClassInfo
-if sys.version_info >= (3, 10):
-    _ClassInfo: TypeAlias = type | UnionType | tuple["_ClassInfo", ...]
-else:
-    _ClassInfo: TypeAlias = Union[type, tuple["_ClassInfo", ...]]
-
-
 T_co = TypeVar("T_co", covariant=True)
 
 

ibis/common/typing.py

@@ -2,11 +2,13 @@
 
 import sys
 from itertools import zip_longest
+from types import ModuleType  # noqa: F401
 from typing import (
     Any,
     Generic,  # noqa: F401
     Optional,
     TypeVar,
+    Union,
     get_args,
     get_origin,
 )
@@ -16,8 +18,15 @@
 
 if sys.version_info >= (3, 10):
     from types import UnionType
+    from typing import TypeAlias
+
+    # Keep this alias in sync with unittest.case._ClassInfo
+    _ClassInfo: TypeAlias = type | UnionType | tuple["_ClassInfo", ...]
 else:
+    from typing_extensions import TypeAlias  # noqa: TCH002
+
     UnionType = object()
+    _ClassInfo: TypeAlias = Union[type, tuple["_ClassInfo", ...]]
 
 
 T = TypeVar("T")