COMP: Modernize Python3 module build

[hjmjohnson]

• Relocate Python LIMITED_API logic for modularity
  o Python configuration should be done in ITKSetPytnon3Vars.cmake.
  It was previously spread around in different parts of the ITK
  package which made tracking of behaviors difficult to monitor.

• Simplify logic for ITK_USE_PYTHON_LIMITED_API
  o Avoid using a temporary variable use_python_limited_api_default to
  set the value of ITK_USE_PYTHON_LIMITED_API.
  o Prefer to set ITK_USE_PYTHON_LIMITED_API directly.
  0 Moved Python LIMITED_API and package component logic to
  ITKSetPython3Vars.cmake for improved organization and maintainability.

• Ensure subsequent find Python3 use same version
  o When calling find_package(Python3 multiple times
  ensure that the same PYTHON_VERSION is used
  for each call.

• Changed Python header inclusion to use angle brackets for consistency.
  o Added include directory properties for itkPyCommand.cxx to improve
  o Python wrapping configuration.

• Remove unused cmake variables
  o Deleted redundant ITKCommon_SYSTEM_INCLUDE_DIRS and
  o ITKCommon_SYSTEM_LIBRARY_DIRS setup for Python when ITK_WRAP_PYTHON is
  enabled.

• These variable are no longer used anywhere in ITK:
  o ITKCommon_SYSTEM_INCLUDE_DIRS
  o ITKCommon_SYSTEM_LIBRARY_DIRS

• Remove redundant MSVC Python linking logic
  o Removed unnecessary link_directories usage for MSVC in Python wrapping
  logic as it relies on outdated CMake features and is no longer required.
  Simplified the code for maintainability.

PR Checklist

• No API changes were made (or the changes have been approved)
• No major design changes were made (or the changes have been approved)

[dzenanz]

Thank you for working on this Hans!

[dzenanz]

It looks like you accidentally deleted CMake/itkTargetLinkLibrariesWithDynamicLookup.cmake.

[hjmjohnson]

It looks like you accidentally deleted CMake/itkTargetLinkLibrariesWithDynamicLookup.cmake.

Yes. This is no longer needed. The Python3_add_module() performs the necessary steps in 3.20 and greater. This correct behavior testing from 2015 predates cmake support. This is now redundant and no longer used.

[thewtex]

A number of the removed features are not testing in CI, so we need to check:

• ITKPythonPackage builds and passes tests with this branch (especially on Windows)
• @SimonRit or @LucasGandel verify that this does not break their modules, e.g. the ITKCudaCommon, that may reference external shared libraries, especially on Windows

[hjmjohnson]

@thewtex Thanks for pointing me in the direction of the most difficult builds. I have a windows VM that I am trying to setup to do these tests. If you have any other pointers to documentation of how to setup and test windows python I would really appreciate it.

[thewtex]

@hjmjohnson great, thanks for testing.

More on Windows builds is here:

https://github.com/InsightSoftwareConsortium/ITK/blob/main/Documentation/Maintenance/Release.md#generate-release-itk-python-wheels

And for remote modules:

https://github.com/InsightSoftwareConsortium/ITKRemoteModuleBuildTestPackageAction/blob/main/.github/workflows/build-test-package-python.yml#L310-L342

[hjmjohnson]

Finding a windows computer that can build ITK with the environments that need testing is more challenging than expected. I'm working on it.

[SimonRit]

A number of the removed features are not testing in CI, so we need to check:

* [ ]  ITKPythonPackage builds and passes tests with this branch (especially on Windows)

* [ ]  @SimonRit or @LucasGandel verify that this does not break their modules, e.g. the ITKCudaCommon, that may reference external shared libraries, especially on Windows

Sorry, I missed your message. I tested the full compilation on Ubuntu of the wrappings with the main branches of CudaCommon and RTK. It seems to work. I'll try to do the same on Windows. Anything else I should try?

[hjmjohnson]

Thanks, Simon.

I am working on building packages using the ITKPythonPackage system as well.

I appreciate your assistance with checking.

FYI: During setting up a Windows system, I was sidetracked with other Windows build issues that I have been trying to address.

Hans

[hjmjohnson]

@thewtex This builds with ITKPythonPackage (after changing ITKPythonPackage to allow for building an untagged version of ITK). It has taken me a long time to figure out how to get ITKPythonPackage to not use the itk6.0b01 tag and use my git tag for testing, but once I got ITKPythonPackage to compile my branch, all worked without a problem.

[dzenanz]

I have not tried using this. Code mostly looks good.

[dzenanz]

OK I am now trying to build this locally.

[dzenanz]

Building locally was successful, though I only tried a few configurations.