CMake object library dependencies leak into exports

[Neurofibromin]

What version of OR-Tools and what language are you using?
Version: v9.15
Language: C++
cmake version 4.3.2

Which solver are you using (e.g. CP-SAT, Routing Solver, GLOP, BOP, Gurobi)
none, this is a cmake issue

What operating system (Linux, Windows, ...) and version?
Linux

What did you do?
Steps to reproduce the behavior:

1. Create cmake project that tries to consume or-tools

if(NOT ORTOOLS_FOUND)
  find_package(ortools CONFIG QUIET
    HINTS ${_ortools_hints}
    PATHS ${_ortools_search_paths}
    PATH_SUFFIXES lib/cmake/ortools)
  if(TARGET ortools::ortools)
    set(ORTOOLS_LIBRARIES ortools::ortools)
    get_target_property(_ortools_inc ortools::ortools INTERFACE_INCLUDE_DIRECTORIES)
    if(_ortools_inc)
      set(ORTOOLS_INCLUDE_DIRS "${_ortools_inc}")
    endif()
    if(DEFINED ortools_VERSION)
      set(ORTOOLS_VERSION "${ortools_VERSION}")
    endif()
  endif()
endif()
...
target_link_libraries(my_target PRIVATE ortools::ortools)

3. Run cmake
4. See error

What did you expect to see
CMake configuration and generation to complete successfully, producing valid build files.

What did you see instead?

-- Found OR-Tools 9.15.9999 -- FindORTOOLS.cmake
-- Configuring done (0.8s)
-- Generating done (0.2s)
CMake Error:
  Error evaluating generator expression:

    $<TARGET_OBJECTS:ortools_math_opt_core>

  Objects of target "ortools_math_opt_core" referenced but no such target exists.

CMake Error:
  Error evaluating generator expression:

    $<TARGET_OBJECTS:ortools_math_opt_constraints_indicator>

  Objects of target "ortools_math_opt_constraints_indicator" referenced but no such target exists.

-- Build files have been written to: ...
[Failed to reload]

Anything else we should know about your project / environment

some ideas about resolution
CMakeLists.txt target_sources is called with the PUBLIC keyword for $<TARGET_OBJECTS:...>:
ortools/math_opt/CMakeLists.txt:

cmaketarget_sources(${NAME} PUBLIC   # <<< maybe should be private?
  $<TARGET_OBJECTS:${NAME}_core>
  $<TARGET_OBJECTS:${NAME}_core_c_api>
  $<TARGET_OBJECTS:${NAME}_cpp>
  $<TARGET_OBJECTS:${NAME}_elemental>
  $<TARGET_OBJECTS:${NAME}_io>
  $<TARGET_OBJECTS:${NAME}_labs>
  $<TARGET_OBJECTS:${NAME}_solvers>
  $<TARGET_OBJECTS:${NAME}_storage>
  $<TARGET_OBJECTS:${NAME}_validators>
)

ortools/math_opt/constraints/CMakeLists.txt

cmaketarget_sources(${NAME} PUBLIC   # <<< same 
  $<TARGET_OBJECTS:${NAME}_indicator>
  $<TARGET_OBJECTS:${NAME}_quadratic>
  $<TARGET_OBJECTS:${NAME}_second_order_cone>
  $<TARGET_OBJECTS:${NAME}_sos>
  $<TARGET_OBJECTS:${NAME}_util>
)

and then:
install(TARGETS ortools_math_opt EXPORT ortoolsTargets)
Using PUBLIC propagates these $<TARGET_OBJECTS:...> expressions into the exported target's INTERFACE_SOURCES and INTERFACE_LINK_LIBRARIES.