[CMake] Transitive linking and imported targets

[Tobias Rudolph]

Hi All,

I am trying to build a project containing several subprojects that are  
included via add_subdirectory. Now, here is an example demonstrating  
the problem:

The test project contains the following CMakeLists.txt:
----
project( CMakeTest )
cmake_minimum_required( VERSION 2.6 )

add_subdirectory( libFoo )

add_executable( TestApp main.cpp )
target_link_libraries( TestApp libFoo )
----

The CMakeLists.txt of the subdirectory libFoo:
----
add_library( iLib SHARED IMPORTED )
set_target_properties( iLib PROPERTIES IMPORTED_LOCATION "/opt/local/ 
lib/libzip.dylib" )

add_library( libFoo SHARED foo.cpp )
target_link_libraries( libFoo iLib )
----

According to the documentation, the imported target (iLib) is only  
know within libFoo and its subdirectories. So, when I try to link  
'TestApp', it fails because the linker is looking for 'iLib' rather  
than '/opt/local/lib/libzip.dylib' due transitive linking (I suspect).

Is that intended behavior?

Best regards,
Tobias