target_link_libraries erroneously pulls in MODULE library at link time - module

Question

I have two C++ projects using CMake 3.12.2.
The first one is MODULE library (a dynamically loaded plugin). It installs a DLL, a header file and the configuration file for CMake.
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(MyPlugin LANGUAGES CXX)
set(CMAKE_DEBUG_POSTFIX "d")
# MODULE libraries are dynamically loaded at runtime and never linked against
add_library(MyPlugin MODULE
include/a.h
src/a.cpp
src/b.h
src/b.cpp
)
target_include_directories(MyPlugin
PUBLIC
$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
$<INSTALL_INTERFACE:include/MyPlugin>
PRIVATE
src
)
install(TARGETS MyPlugin EXPORT MyPluginConfig
# MODULE libraries are installed as LIBRARY
LIBRARY DESTINATION plugins COMPONENT Runtime
RUNTIME DESTINATION bin COMPONENT Runtime
PUBLIC_HEADER DESTINATION include/MyPlugin COMPONENT Development
)
install(FILES $<TARGET_PDB_FILE:MyPlugin> DESTINATION plugins OPTIONAL COMPONENT Runtime)
install(
DIRECTORY include/
DESTINATION include/MyPlugin
FILES_MATCHING PATTERN "*.h"
)
install(EXPORT MyPluginConfig
NAMESPACE MyPlugin::
DESTINATION lib/cmake/MyPlugin
)
The second one is a simple executable which pulls in the header file of the plugin via target_link_libraries (the modern CMake way).
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(MyExe LANGUAGES CXX)
set(CMAKE_DEBUG_POSTFIX "d")
find_package(MyPlugin REQUIRED)
add_executable(MyExe src/main.cpp)
target_link_libraries(MyExe MyPlugin::MyPlugin)
Using the vs2015 generated solution the link fails because the plugin DLL is fed during the link of the executable...
Has anyone a solution for this or should I file a bug?
Regards.

Answer 1

A solution to this issue is to split the library in two: an interface library which only provides the headers and a module library which does not export any header.
The module library CMakeLists.txt becomes:
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(MyPlugin LANGUAGES CXX)
set(CMAKE_DEBUG_POSTFIX "d")
# Move public headers to a dedicated INTERFACE library
add_library(MyPluginInterface INTERFACE)
add_custom_target(Includes SOURCES include/a.h)
target_include_directories(MyPluginInterfacecmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(MyPlugin LANGUAGES CXX)
set(CMAKE_DEBUG_POSTFIX "d")
# Move public headers to a dedicated INTERFACE library
add_library(MyPluginInterface INTERFACE)
add_custom_target(Includes SOURCES include/a.h)
target_include_directories(MyPluginInterface
INTERFACE
$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
$<INSTALL_INTERFACE:include/MyPlugin>
)
install(TARGETS MyPluginInterface EXPORT MyPluginConfig
PUBLIC_HEADER DESTINATION include/MyPlugin COMPONENT Development
)
# MODULE libraries are dynamically loaded at runtime and never linked against
add_library(MyPlugin MODULE
src/a.cpp
src/b.h
src/b.cpp
)
target_link_libraries(MyPlugin MyPluginInterface)
install(TARGETS MyPlugin
# MODULE libraries are installed as LIBRARY
LIBRARY DESTINATION plugins COMPONENT Runtime
RUNTIME DESTINATION bin COMPONENT Runtime
)
install(FILES $<TARGET_PDB_FILE:MyPlugin> DESTINATION plugins OPTIONAL COMPONENT Runtime)
install(
DIRECTORY include/
DESTINATION include/MyPlugin
FILES_MATCHING PATTERN "*.h"
)
install(EXPORT MyPluginConfig
NAMESPACE MyPlugin::
DESTINATION lib/cmake/MyPlugin
)
INTERFACE
$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
$<INSTALL_INTERFACE:include/MyPlugin>
)
install(TARGETS MyPluginInterface EXPORT MyPluginConfig
PUBLIC_HEADER DESTINATION include/MyPlugin COMPONENT Development
)
# MODULE libraries are dynamically loaded at runtime and never linked against
add_library(MyPlugin MODULE
src/a.cpp
src/b.h
src/b.cpp
)
target_link_libraries(MyPlugin MyPluginInterface)
install(TARGETS MyPlugin
# MODULE libraries are installed as LIBRARY
LIBRARY DESTINATION plugins COMPONENT Runtime
RUNTIME DESTINATION bin COMPONENT Runtime
)
install(FILES $<TARGET_PDB_FILE:MyPlugin> DESTINATION plugins OPTIONAL COMPONENT Runtime)
install(
DIRECTORY include/
DESTINATION include/MyPlugin
FILES_MATCHING PATTERN "*.h"
)
install(EXPORT MyPluginConfig
NAMESPACE MyPlugin::
DESTINATION lib/cmake/MyPlugin
)
The executable CMakeLists.txt becomes:
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(MyExe LANGUAGES CXX)
set(CMAKE_DEBUG_POSTFIX "d")
find_package(MyPlugin REQUIRED)
add_executable(MyExe src/main.cpp)
target_link_libraries(MyExe MyPlugin::MyPluginInterface)