[dzenanz]

On Windows, import itk; itk.force_load() failed with DLL load failed while importing _ITKVtkGluePython against a multi-config VTK build tree. ITKVtkGlueConfig.py now registers VTK's DLL directory, so users don't need os.add_dll_directory or an import vtkmodules first.

Root cause

Python >= 3.8 ignores PATH for an extension's dependent DLLs. vtkmodules only registers <prefix>/bin, but Visual Studio builds of VTK put their DLLs in bin/<config>. A complementary VTK change adds those directories to vtkmodules/_build_paths.py. The two changes don't conflict: registering the same directory twice is harmless.

import itk imports every itk/Configuration/*Config.py, so a new ITK_WRAP_PYTHON_CONFIGURATION_PREAMBLE placeholder in ModuleConfig.py.in runs before VtkGlue or vtkmodules loads. Modules that leave it empty generate the same file as before. VtkGlue sets it on Windows only, to the directory of VTK::CommonCore for CMAKE_BUILD_TYPE, or for Release in multi-config builds.

No CI configuration enables Module_ITKVtkGlue, which is why CI didn't catch this.

AI assistance

• Claude Code diagnosed the failure and wrote the change and test adjustments.
• Local Windows/VS2022 Release build with Python wrapping and VTK_DIR pointing to a VTK 9.7 VS2022 build tree: PythonVtkGlue*, PythonFindEmptyClasses, PythonGetNameOfClass, PythonTiming, PythonBuildOptions, PythonVerify*APIConsistency, PythonTypeTest and PythonExtrasTest all pass (11/11).

🤖 Generated with Claude Code

[hjmjohnson]

LGTM

[greptile-apps]

Confidence Score: 4/5

[Medium impact] The change reaches Windows users of Python-wrapped ITKVtkGlue.

Fix the generated path quoting before merging; a valid Windows directory can currently prevent ITK from importing.

Findings

1.  Apostrophes break ITK imports ▶

Summary

Adds a per-module Python preamble so Windows builds register VTK's DLL directory during import itk.

• ITK registers VTK’s DLL folder before loading its Python modules.

_{Reviews (1) · Last reviewed commit: "BUG: Register VTK's DLL directory at imp..." · Reviewed by Greptile}