From 6d6949547f636c34b4ca375b73a56afd8c019bdc Mon Sep 17 00:00:00 2001
From: Hans Johnson <hans-johnson@uiowa.edu>
Date: Fri, 3 Jul 2026 15:17:35 -0500
Subject: [PATCH] Fixed build-tree export references for superproject builds.

The build-tree DCMTKTargets.cmake is written by
export(TARGETS ... NAMESPACE DCMTK::), which prefixes DCMTK:: onto
every in-build target referenced by the exported link interfaces,
including targets owned by a superproject that vendors DCMTK via
add_subdirectory() or FetchContent() (e.g. a codec target supplied
through ZLIB_LIBRARIES). The export then records nonexistent targets
such as DCMTK::ITK::ITKZLIBModule or DCMTK::super_zlibwrap, and any
external consumer of the superproject's build tree that imports
DCMTKConfig fails at CMake generate with 'target ... not found'. The
install-tree export is written by install(EXPORT) and resolves the
same references correctly.

All genuine DCMTK:: targets are defined once DCMTKConfig.cmake has
included DCMTKTargets.cmake, so strip the mis-applied prefix from any
DCMTK::-prefixed link-interface reference that is not an existing
target. For the install tree and for standalone builds the loop is a
no-op.
---
 CMake/DCMTKConfig.cmake.in | 42 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/CMake/DCMTKConfig.cmake.in b/CMake/DCMTKConfig.cmake.in
index 5a18695ff..625884663 100644
--- a/CMake/DCMTKConfig.cmake.in
+++ b/CMake/DCMTKConfig.cmake.in
@@ -173,4 +173,46 @@ endif()
 if(NOT DCMTK_TARGETS_IMPORTED)
   set(DCMTK_TARGETS_IMPORTED 1)
   include(${DCMTK_TARGETS})
+  # When DCMTK is built inside a superproject (add_subdirectory/FetchContent),
+  # the build-tree export written by export(TARGETS ... NAMESPACE DCMTK::)
+  # also prefixes DCMTK:: onto link-interface targets owned by the
+  # superproject, recording nonexistent targets such as
+  # DCMTK::ITK::ITKZLIBModule or DCMTK::super_zlibwrap. All genuine DCMTK::
+  # targets were just defined by the include() above, so strip the
+  # mis-applied prefix from any DCMTK::-prefixed reference that is not an
+  # existing target. The install-tree export is written by install(EXPORT)
+  # and is unaffected; there this loop is a no-op.
+  foreach(_dcmtk_lib @DCMTK_LIBRARY_TARGETS@)
+    if(TARGET DCMTK::${_dcmtk_lib})
+      get_target_property(_dcmtk_ll DCMTK::${_dcmtk_lib} INTERFACE_LINK_LIBRARIES)
+      if(_dcmtk_ll)
+        set(_dcmtk_ll_new "")
+        foreach(_dcmtk_entry IN LISTS _dcmtk_ll)
+          set(_dcmtk_name "${_dcmtk_entry}")
+          set(_dcmtk_link_only 0)
+          if(_dcmtk_entry MATCHES "^\\$<LINK_ONLY:(.+)>$")
+            set(_dcmtk_name "${CMAKE_MATCH_1}")
+            set(_dcmtk_link_only 1)
+          endif()
+          if(_dcmtk_name MATCHES "^DCMTK::(.+)$" AND NOT TARGET "${_dcmtk_name}")
+            set(_dcmtk_name "${CMAKE_MATCH_1}")
+          endif()
+          if(_dcmtk_link_only)
+            list(APPEND _dcmtk_ll_new "$<LINK_ONLY:${_dcmtk_name}>")
+          else()
+            list(APPEND _dcmtk_ll_new "${_dcmtk_name}")
+          endif()
+        endforeach()
+        if(NOT "${_dcmtk_ll_new}" STREQUAL "${_dcmtk_ll}")
+          set_target_properties(DCMTK::${_dcmtk_lib} PROPERTIES INTERFACE_LINK_LIBRARIES "${_dcmtk_ll_new}")
+        endif()
+        unset(_dcmtk_ll_new)
+        unset(_dcmtk_entry)
+        unset(_dcmtk_name)
+        unset(_dcmtk_link_only)
+      endif()
+      unset(_dcmtk_ll)
+    endif()
+  endforeach()
+  unset(_dcmtk_lib)
 endif()