rf: Hide typing backports in helper module

Author: effigies

nibabel/_typing.py

@@ -0,0 +1,25 @@
+"""Helpers for typing compatibility across Python versions"""
+
+import sys
+
+if sys.version_info < (3, 10):
+    from typing_extensions import ParamSpec
+else:
+    from typing import ParamSpec
+
+if sys.version_info < (3, 11):
+    from typing_extensions import Self
+else:
+    from typing import Self
+
+if sys.version_info < (3, 13):
+    from typing_extensions import TypeVar
+else:
+    from typing import TypeVar
+
+
+__all__ = [
+    'ParamSpec',
+    'Self',
+    'TypeVar',
+]

nibabel/arrayproxy.py

@@ -59,10 +59,11 @@
 
 if ty.TYPE_CHECKING:
     import numpy.typing as npt
-    from typing_extensions import Self  # PY310
+
+    from ._typing import Self, TypeVar
 
     # Taken from numpy/__init__.pyi
-    _DType = ty.TypeVar('_DType', bound=np.dtype[ty.Any])
+    _DType = TypeVar('_DType', bound=np.dtype[ty.Any])
 
 
 class ArrayLike(ty.Protocol):

nibabel/dataobj_images.py

@@ -14,6 +14,7 @@
 
 import numpy as np
 
+from ._typing import TypeVar
 from .deprecated import deprecate_with_version
 from .filebasedimages import FileBasedHeader, FileBasedImage
 
@@ -24,13 +25,13 @@
     from .fileholders import FileMap
     from .filename_parser import FileSpec
 
-    FT = ty.TypeVar('FT', bound=np.floating)
+    FT = TypeVar('FT', bound=np.floating)
     F16 = ty.Literal['float16', 'f2', '|f2', '=f2', '<f2', '>f2']
     F32 = ty.Literal['float32', 'f4', '|f4', '=f4', '<f4', '>f4']
     F64 = ty.Literal['float64', 'f8', '|f8', '=f8', '<f8', '>f8']
     Caching = ty.Literal['fill', 'unchanged']
 
-ArrayImgT = ty.TypeVar('ArrayImgT', bound='DataobjImage')
+ArrayImgT = TypeVar('ArrayImgT', bound='DataobjImage')
 
 
 class DataobjImage(FileBasedImage):

nibabel/deprecated.py

@@ -5,15 +5,11 @@
 import typing as ty
 import warnings
 
+from ._typing import ParamSpec
 from .deprecator import Deprecator
 from .pkg_info import cmp_pkg_version
 
-if ty.TYPE_CHECKING:
-    # PY39: ParamSpec is available in Python 3.10+
-    P = ty.ParamSpec('P')
-else:
-    # Just to keep the runtime happy
-    P = ty.TypeVar('P')
+P = ParamSpec('P')
 
 
 class ModuleProxy:

nibabel/deprecator.py

@@ -10,8 +10,10 @@
 from textwrap import dedent
 
 if ty.TYPE_CHECKING:
-    T = ty.TypeVar('T')
-    P = ty.ParamSpec('P')
+    from ._typing import ParamSpec, TypeVar
+
+    T = TypeVar('T')
+    P = ParamSpec('P')
 
 _LEADING_WHITE = re.compile(r'^(\s*)')
 

nibabel/filebasedimages.py

@@ -16,6 +16,7 @@
 from urllib import request
 
 from ._compression import COMPRESSION_ERRORS
+from ._typing import TypeVar
 from .fileholders import FileHolder, FileMap
 from .filename_parser import TypesFilenamesError, _stringify_path, splitext_addext, types_filenames
 from .openers import ImageOpener
@@ -25,10 +26,10 @@
 
 FileSniff = tuple[bytes, str]
 
-ImgT = ty.TypeVar('ImgT', bound='FileBasedImage')
-HdrT = ty.TypeVar('HdrT', bound='FileBasedHeader')
+ImgT = TypeVar('ImgT', bound='FileBasedImage')
+HdrT = TypeVar('HdrT', bound='FileBasedHeader')
 
-StreamImgT = ty.TypeVar('StreamImgT', bound='SerializableImage')
+StreamImgT = TypeVar('StreamImgT', bound='SerializableImage')
 
 
 class ImageFileError(Exception):

nibabel/loadsave.py

@@ -27,10 +27,11 @@
 
 
 if ty.TYPE_CHECKING:
+    from ._typing import ParamSpec
     from .filebasedimages import FileBasedImage
     from .filename_parser import FileSpec
 
-    P = ty.ParamSpec('P')
+    P = ParamSpec('P')
 
     class Signature(ty.TypedDict):
         signature: bytes

nibabel/nifti1.py

@@ -14,20 +14,15 @@
 from __future__ import annotations
 
 import json
-import sys
 import typing as ty
 import warnings
 from io import BytesIO
 
 import numpy as np
 import numpy.linalg as npl
 
-if sys.version_info < (3, 13):
-    from typing_extensions import Self, TypeVar  # PY312
-else:
-    from typing import Self, TypeVar
-
 from . import analyze  # module import
+from ._typing import Self, TypeVar
 from .arrayproxy import get_obj_dtype
 from .batteryrunners import Report
 from .casting import have_binary128

nibabel/openers.py

@@ -22,7 +22,8 @@
     from types import TracebackType
 
     from _typeshed import WriteableBuffer
-    from typing_extensions import Self
+
+    from ._typing import Self
 
     ModeRT = ty.Literal['r', 'rt']
     ModeRB = ty.Literal['rb']

nibabel/pointset.py

@@ -31,9 +31,9 @@
 from nibabel.spatialimages import SpatialImage
 
 if ty.TYPE_CHECKING:
-    from typing_extensions import Self
+    from ._typing import Self, TypeVar
 
-    _DType = ty.TypeVar('_DType', bound=np.dtype[ty.Any])
+    _DType = TypeVar('_DType', bound=np.dtype[ty.Any])
 
 
 class CoordinateArray(ty.Protocol):