2nd attempt in solving windows linking

Author: Luispain

CMakeLists.txt

@@ -191,9 +191,8 @@ set_target_properties(core_objects PROPERTIES
 )
 
 target_include_directories(core_objects PUBLIC ${PYBIND11_INCLUDE_DIRS})
-# BUILDING_NODE_LIBRARY must not leak to static library consumers on Windows,
-# otherwise headers mark Node symbols as dllimport/dllexport and MSVC links
-# against import stubs that do not exist for static linkage.
+# core_objects contributes to both static and shared variants; compile with
+# export annotations enabled where definitions are emitted.
 target_compile_definitions(core_objects PRIVATE BUILDING_NODE_LIBRARY)
 # Keep pybind11 usage requirements attached to the object target so core
 # sources that include <pybind11/...> (e.g. numpy.h) always compile.
@@ -215,13 +214,6 @@ target_link_libraries(core_static PUBLIC
     ${NUMPY_LIBRARIES}
 )
 
-if(MSVC)
-    # Core modules currently link against core_static on Windows.
-    # Force neutral visibility macro for those consumers to avoid
-    # __declspec(dllimport) decoration when no DLL import lib is used.
-    target_compile_definitions(core_static PUBLIC NODE_EXPORT=)
-endif()
-
 add_library(core_shared SHARED $<TARGET_OBJECTS:core_objects>)
 set_target_properties(core_shared PROPERTIES
     CXX_VISIBILITY_PRESET default
@@ -239,6 +231,17 @@ target_link_libraries(core_shared PUBLIC
     ${NUMPY_LIBRARIES}
 )
 
+# Linking strategy by platform:
+# - MSVC: link extension modules against core_shared to avoid static-link
+#   import/export decoration mismatches.
+# - Other platforms: keep static linkage to preserve previous Linux/macOS
+#   behavior that avoids unresolved symbols from split modules.
+if(MSVC)
+    set(CORE_LINK_TARGET core_shared)
+else()
+    set(CORE_LINK_TARGET core_static)
+endif()
+
 if(APPLE)
     set_target_properties(core_shared PROPERTIES
         INSTALL_RPATH "@loader_path"
@@ -304,15 +307,15 @@ if(ENABLE_MPI)
 endif()
 
 pybind11_add_module(core MODULE src/c++/core_pybind.cpp)
-target_link_libraries(core PRIVATE core_static)
-add_dependencies(core core_static)
+target_link_libraries(core PRIVATE ${CORE_LINK_TARGET})
+add_dependencies(core ${CORE_LINK_TARGET})
 if(APPLE)
     target_link_options(core PRIVATE "-Wl,-rpath,@loader_path")
 endif()
 
 pybind11_add_module(_cgns MODULE src/c++/cgns_pybind.cpp)
-target_link_libraries(_cgns PRIVATE core_static)
-add_dependencies(_cgns core_static)
+target_link_libraries(_cgns PRIVATE ${CORE_LINK_TARGET})
+add_dependencies(_cgns ${CORE_LINK_TARGET})
 if(APPLE)
 target_link_options(_cgns PRIVATE "-Wl,-rpath,@loader_path")
 endif()
@@ -332,9 +335,9 @@ install(DIRECTORY include DESTINATION ${SKBUILD_PROJECT_NAME})
 # if(ENABLE_TESTS)
 #     file(GLOB_RECURSE TEST_FILES "tests/*.cpp" "tests/*.hpp")
 #     pybind11_add_module(tests MODULE ${TEST_FILES})
-#     target_link_libraries(tests PRIVATE core_static)
+#     target_link_libraries(tests PRIVATE ${CORE_LINK_TARGET})
 #     target_include_directories(tests PRIVATE ${CMAKE_INSTALL_INCLUDEDIR} ${CMAKE_SOURCE_DIR}/tests)
-#     add_dependencies(tests core_static)
+#     add_dependencies(tests ${CORE_LINK_TARGET})
 #     if(APPLE)
 #         target_link_options(tests PRIVATE "-Wl,-rpath,@loader_path")
 #     endif()
@@ -356,12 +359,12 @@ if(ENABLE_TESTS)
         CXX_VISIBILITY_PRESET default
         VISIBILITY_INLINES_HIDDEN OFF
     )
-    target_link_libraries(tests PRIVATE core_static)
+    target_link_libraries(tests PRIVATE ${CORE_LINK_TARGET})
     target_include_directories(tests PRIVATE
         ${CMAKE_INSTALL_INCLUDEDIR}
         ${CMAKE_SOURCE_DIR}/tests
     )
-    add_dependencies(tests core_static)
+    add_dependencies(tests ${CORE_LINK_TARGET})
 
     if(APPLE)
         target_link_options(tests PRIVATE "-Wl,-rpath,@loader_path")