From 77c1df1700e8f4de6e8cb50f0c31b36cbf0b4536 Mon Sep 17 00:00:00 2001
From: Bradley Lowekamp <blowekamp@mail.nih.gov>
Date: Tue, 3 Feb 2026 17:02:26 +0000
Subject: [PATCH] BUG: Disable adding dependency for externally built modules

When a module is built outside of the ITK source, do not add the
module as a dependency to the factory meta-module.
---
 CMake/ITKModuleMacros.cmake | 41 +++++++++++++++++++++++++++++++------
 1 file changed, 35 insertions(+), 6 deletions(-)

diff --git a/CMake/ITKModuleMacros.cmake b/CMake/ITKModuleMacros.cmake
index f60c236d614..0356b17ee0c 100644
--- a/CMake/ITKModuleMacros.cmake
+++ b/CMake/ITKModuleMacros.cmake
@@ -423,12 +423,41 @@ endif()
       )
       set(_meta_module ITK${_factory_name})
 
-      # Add this module to the factory meta-module
-      target_link_libraries(
-        ${_meta_module}
-        INTERFACE
-          ${ITK_MODULE_${itk-module}_TARGETS_NAMESPACE}${itk-module}Module
-      )
+      if(NOT TARGET ${_meta_module})
+        # When building a module outside ITK source tree, the factory meta-module may not be defined yet.
+        message(
+          STATUS
+          "Not adding ${itk-module}Module(${_factory_format}) to factory meta-module ${_meta_module} because it is outside ITK source tree."
+        )
+      else()
+        get_target_property(_is_imported ${_meta_module} IMPORTED)
+        if(_is_imported)
+          message(
+            DEBUG
+            "Not adding ${itk-module}Module(${_factory_format}) to factory meta-module ${_meta_module} because it is an imported target. "
+          )
+        else()
+          # Check if this module is already linked to the factory meta-module
+          set(
+            _module_target
+            ${ITK_MODULE_${itk-module}_TARGETS_NAMESPACE}${itk-module}Module
+          )
+          get_target_property(
+            _existing_deps
+            ${_meta_module}
+            INTERFACE_LINK_LIBRARIES
+          )
+          if(_existing_deps AND "${_module_target}" IN_LIST _existing_deps)
+            message(
+              DEBUG
+              "Module ${itk-module}Module is already linked to factory meta-module ${_meta_module}."
+            )
+          else()
+            # Add this module to the factory meta-module
+            target_link_libraries(${_meta_module} INTERFACE ${_module_target})
+          endif()
+        endif()
+      endif()
     endforeach()
   endif()