ENH: Update to minimum Python support to py310

.pre-commit-config.yaml

@@ -74,15 +74,15 @@ repos:
   rev: 24.2.0
   hooks: # check conformance to black formatting
    - id: black
-     #args: ['--diff', '-v', '--target-version', 'py39' ] # if run without arguments, will fail and will format the files
-     args: ['--target-version', 'py39' ] # Allow black to fail and provide auto-formatting to files that need it for compliance
+     #args: ['--diff', '-v', '--target-version', 'py310' ] # if run without arguments, will fail and will format the files
+     args: ['--target-version', 'py310' ] # Allow black to fail and provide auto-formatting to files that need it for compliance
      exclude: ".*build.*|\\/ThirdParty\\/|\\/Data\\/"
 -   repo: https://github.com/asottile/pyupgrade
     rev: v3.19.0
     hooks:
     -   id: pyupgrade
         exclude: ".*build.*|\\/ThirdParty\\/|\\/Data\\/"
-        args: [--py39-plus]
+        args: [--py310-plus]
 - repo: https://github.com/SimpleITK/CommentSpellCheck.git
   rev: v0.4.4
   hooks:

Documentation/docs/contributing/python_packaging.md

@@ -20,7 +20,7 @@ Building ITK Python wheels requires the following:
 - CMake >= 3.16
 - Git
 - C++ Compiler (see [scikit-build platform specific requirements](https://scikit-build.readthedocs.io/en/latest/generators.html))
-- Python >= 3.9
+- Python >= 3.10
 
 ## Automated Platform Scripts
 
@@ -40,11 +40,11 @@ git clone https://github.com/InsightSoftwareConsortium/ITKPythonPackage.git
 
 pushd ITKPythonPackage
 export MANYLINUX_VERSION=2014
-./scripts/dockcross-manylinux-build-wheels.sh cp38
+./scripts/dockcross-manylinux-build-wheels.sh cp310
 [...]
 
 ls -1 dist/
-itk-5.3.0.dev20231108-cp38-cp38m-manylinux2014_x86_64.whl
+itk-6.0.0.dev20260401-cp310-cp310-manylinux2014_x86_64.whl
 ```
 
 ### macOS
@@ -61,11 +61,11 @@ Then, run [macpython-build-wheels.sh](https://github.com/InsightSoftwareConsorti
 git clone https://github.com/InsightSoftwareConsortium/ITKPythonPackage.git
 [...]
 
-./scripts/macpython-build-wheels.sh cp38
+./scripts/macpython-build-wheels.sh cp310
 [...]
 
 ls -1 dist/
-itk-5.3.0.dev20231108-cp38-cp38m-macosx_10_9_x86_64.whl
+itk-6.0.0.dev20260401-cp310-cp310-macosx_11_0_arm64.whl
 ```
 
 ### Windows

Testing/ContinuousIntegration/AzurePipelinesLinux.yml

@@ -245,7 +245,7 @@ jobs:
       displayName: "Checkout pull request HEAD"
     - task: UsePythonVersion@0
       inputs:
-        versionSpec: "3.9"
+        versionSpec: "3.10"
         architecture: "x64"
     - bash: |
         set -x

Wrapping/Generators/Python/CMakeLists.txt

@@ -166,7 +166,7 @@ if(NOT EXTERNAL_WRAP_ITK_PROJECT)
   )
 
   configure_file(
-    "${CMAKE_CURRENT_SOURCE_DIR}/itkConfig.py.in"
+    "${CMAKE_CURRENT_SOURCE_DIR}/itkConfig.template.in.py"
     "${ITK_WRAP_PYTHON_ROOT_BINARY_DIR}/itkConfig.py"
     @ONLY
   )

Wrapping/Generators/Python/PyBase/pyBase.i

@@ -12,8 +12,8 @@ import collections
 from sys import version_info as _version_info
 # Set values below to the same value as
 # PYTHON_VERSION_MIN in ITKSetPython3Vars.cmake
-if _version_info < (3, 9, 0):
-    raise RuntimeError("Python 3.9 or later required")
+if _version_info < (3, 10, 0):
+    raise RuntimeError("Python 3.10 or later required")
 
 from . import _ITKCommonPython
 %}

Wrapping/Generators/Python/itk/pyi_generator.py

@@ -10,7 +10,6 @@
 from io import StringIO
 from pathlib import Path, PurePath
 import pickle
-from typing import Union
 import glob
 import re
 from collections import defaultdict
@@ -380,7 +379,7 @@ def write_class_proxy_pyi(
         pyi_file.write(interfaces_code)
 
 
-def unpack(file_names: [str], save_dir: str) -> Union[str, None]:
+def unpack(file_names: [str], save_dir: str) -> str | None:
     class_definitions = []
 
     for file_name in file_names:
@@ -429,7 +428,7 @@ def unpack(file_names: [str], save_dir: str) -> Union[str, None]:
         return None
 
 
-def merge(class_definitions: []) -> Union[ITKClass, None]:
+def merge(class_definitions: []) -> ITKClass | None:
     # Merge all the class files together to return one complete class.
     if len(class_definitions) == 0:
         return None

Wrapping/Generators/Python/itk/support/base.py

@@ -21,7 +21,7 @@
 from sys import stderr as system_error_stream
 
 # Required to work around weird import error with xarray
-from typing import Any, Optional, Union
+from typing import Any
 from collections.abc import Sequence
 
 import itkConfig
@@ -305,7 +305,7 @@ class ITKTemplateFeatures:
     ('Image',       'itk::Image',   'itkImageSS2',   True,            'signed short,2'),
     """
 
-    def __init__(self, feature_tuple: Sequence[Union[str, bool]]) -> None:
+    def __init__(self, feature_tuple: Sequence[str | bool]) -> None:
         feature_length: int = len(feature_tuple)
         # ITK classes have exactly 5 elements in the tuple, otherwise they are swig classes
         self._is_itk_class: bool = feature_length == 5
@@ -317,7 +317,7 @@ def __init__(self, feature_tuple: Sequence[Union[str, bool]]) -> None:
         self._cpp_class_name: str = feature_tuple[1]
         self._swig_class_name: str = feature_tuple[2]
         self._class_in_module: bool = feature_tuple[3] if feature_length >= 4 else False
-        self._template_parameters: Optional[str] = (
+        self._template_parameters: str | None = (
             feature_tuple[4] if feature_length == 5 else None
         )
 

Wrapping/Generators/Python/itk/support/build_options.py

@@ -8,7 +8,6 @@
 from itk.support import types
 from itk.support.template_class import itkTemplate, itkTemplateBase
 
-from typing import Union
 from itkConfig import ITK_GLOBAL_WRAPPING_BUILD_OPTIONS as _itkwrapbo
 
 DIMS: list[int] = [int(s) for s in _itkwrapbo["ITK_WRAP_IMAGE_DIMS"] if s]
@@ -62,7 +61,7 @@
 SCALARS: list[types.itkCType] = INTS + REALS
 VECTORS: list[itkTemplate] = VECTOR_REALS + COV_VECTOR_REALS
 COLORS: list[itkTemplate] = RGBS + RGBAS
-ALL_TYPES: list[Union[types.itkCType, itkTemplate]] = (
+ALL_TYPES: list[types.itkCType | itkTemplate] = (
     COLORS + VECTORS + SCALARS + COMPLEX_REALS
 )