From d31eb569b507399001494a74ad357ede58ff3417 Mon Sep 17 00:00:00 2001
From: "Hans J. Johnson" <hans-johnson@uiowa.edu>
Date: Wed, 2 Sep 2026 08:46:04 -0500
Subject: [PATCH 1/2] STYLE: Break the gersemi / end-of-file-fixer deadlock on
 empty CMakeLists

src/External and src/GPU hold no examples yet, but src/CMakeLists.txt
calls add_subdirectory() on both, so each needs a CMakeLists.txt. With
those files empty, gersemi wrote a lone newline and end-of-file-fixer
stripped it back, so `pre-commit run --all-files` never converged.
Documenting why the files exist gives both hooks something to agree on.

Also applies gersemi's pending reformat of
ComputeCurvatureAnisotropicDiffusion/CMakeLists.txt.
---
 src/External/CMakeLists.txt                   |  3 +-
 .../CMakeLists.txt                            | 47 ++++++++++++-------
 src/GPU/CMakeLists.txt                        |  3 +-
 3 files changed, 34 insertions(+), 19 deletions(-)

diff --git a/src/External/CMakeLists.txt b/src/External/CMakeLists.txt
index 8b1378917..4917e752c 100644
--- a/src/External/CMakeLists.txt
+++ b/src/External/CMakeLists.txt
@@ -1 +1,2 @@
-
+# No examples in this category yet; this file exists because
+# src/CMakeLists.txt calls add_subdirectory(External).
diff --git a/src/Filtering/AnisotropicSmoothing/ComputeCurvatureAnisotropicDiffusion/CMakeLists.txt b/src/Filtering/AnisotropicSmoothing/ComputeCurvatureAnisotropicDiffusion/CMakeLists.txt
index 62596ffa7..cb6bb5ba2 100644
--- a/src/Filtering/AnisotropicSmoothing/ComputeCurvatureAnisotropicDiffusion/CMakeLists.txt
+++ b/src/Filtering/AnisotropicSmoothing/ComputeCurvatureAnisotropicDiffusion/CMakeLists.txt
@@ -2,7 +2,12 @@ cmake_minimum_required(VERSION 3.22.1)
 
 set(input_image ${CMAKE_CURRENT_BINARY_DIR}/BrainProtonDensitySlice.png)
 set(output_image Output.png)
-set(test_options 5 0.125 3.0)
+set(
+  test_options
+  5
+  0.125
+  3.0
+)
 
 project(ComputeCurvatureAnisotropicDiffusion)
 
@@ -10,37 +15,45 @@ find_package(ITK REQUIRED)
 itk_generate_factory_registration()
 
 add_executable(${PROJECT_NAME} Code.cxx)
-target_link_libraries(${PROJECT_NAME}
+target_link_libraries(
+  ${PROJECT_NAME}
   PRIVATE
     ITK::ITKImageIO
     ITK::ITKAnisotropicSmoothingModule
     ITK::ITKImageIntensityModule
 )
 
-install(TARGETS ${PROJECT_NAME}
+install(
+  TARGETS
+    ${PROJECT_NAME}
   DESTINATION bin/ITKSphinxExamples/Filtering/AnisotropicSmoothing
   COMPONENT Runtime
-  )
+)
 
-install(FILES Code.cxx CMakeLists.txt Code.py
-  DESTINATION share/ITKSphinxExamples/Code/Filtering/AnisotropicSmoothing/ComputeCurvatureAnisotropicDiffusion
+install(
+  FILES
+    Code.cxx
+    CMakeLists.txt
+    Code.py
+  DESTINATION
+    share/ITKSphinxExamples/Code/Filtering/AnisotropicSmoothing/ComputeCurvatureAnisotropicDiffusion
   COMPONENT Code
 )
 
 enable_testing()
-add_test(NAME ComputeCurvatureAnisotropicDiffusionTest
-  COMMAND ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${PROJECT_NAME}
-  ${input_image}
-  ${output_image}
-  ${test_options}
+add_test(
+  NAME ComputeCurvatureAnisotropicDiffusionTest
+  COMMAND
+    ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/${PROJECT_NAME} ${input_image}
+    ${output_image} ${test_options}
 )
 
 if(ITK_WRAP_PYTHON)
   string(REPLACE . "Python." output_image "${output_image}")
-  add_test(NAME ComputeCurvatureAnisotropicDiffusionTestPython
-    COMMAND ${Python3_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/Code.py
-      ${input_image}
-      ${output_image}
-      ${test_options}
-    )
+  add_test(
+    NAME ComputeCurvatureAnisotropicDiffusionTestPython
+    COMMAND
+      ${Python3_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/Code.py ${input_image}
+      ${output_image} ${test_options}
+  )
 endif()
diff --git a/src/GPU/CMakeLists.txt b/src/GPU/CMakeLists.txt
index 8b1378917..23f313c2a 100644
--- a/src/GPU/CMakeLists.txt
+++ b/src/GPU/CMakeLists.txt
@@ -1 +1,2 @@
-
+# No examples in this category yet; this file exists because
+# src/CMakeLists.txt calls add_subdirectory(GPU).

From bdc606e3ac9d570b2da3c963a44207b5173ea09f Mon Sep 17 00:00:00 2001
From: "Hans J. Johnson" <hans-johnson@uiowa.edu>
Date: Wed, 2 Sep 2026 08:38:59 -0500
Subject: [PATCH 2/2] COMP: Select the LevelSetNode container index type at
 runtime

ITK 6.0 wraps VectorContainer<IdentifierType, LevelSetNode<...>>; ITK 5.4
wraps VectorContainer<unsigned int, LevelSetNode<...>>. The two mangled
template keys are disjoint, so a single spelling cannot run on both.

Verified against ITK 5.4.6: the example completes in 171 iterations with
RMS change 0.0198.
---
 .../SegmentWithGeodesicActiveContourLevelSet/Code.py   | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/Segmentation/LevelSets/SegmentWithGeodesicActiveContourLevelSet/Code.py b/src/Segmentation/LevelSets/SegmentWithGeodesicActiveContourLevelSet/Code.py
index 7ebf54572..9263336a1 100755
--- a/src/Segmentation/LevelSets/SegmentWithGeodesicActiveContourLevelSet/Code.py
+++ b/src/Segmentation/LevelSets/SegmentWithGeodesicActiveContourLevelSet/Code.py
@@ -99,11 +99,17 @@
 seedPosition[0] = args.seed_x
 seedPosition[1] = args.seed_y
 
-node = itk.LevelSetNode[InputPixelType, Dimension]()
+NodeType = itk.LevelSetNode[InputPixelType, Dimension]
+
+node = NodeType()
 node.SetValue(seedValue)
 node.SetIndex(seedPosition)
 
-seeds = itk.VectorContainer[itk.UI, itk.LevelSetNode[InputPixelType, Dimension]].New()
+try:
+    NodeContainer = itk.VectorContainer[itk.IT, NodeType]  # ITK >= 6.0
+except TypeError:
+    NodeContainer = itk.VectorContainer[itk.UI, NodeType]  # ITK <= 5.4
+seeds = NodeContainer.New()
 seeds.Initialize()
 seeds.InsertElement(0, node)