COMPILE_ONLY: Genex now stops object libraries from linking

Previously we didn't properly exclude $<COMPILE_ONLY:OBJECT lib>
from the right hand side of  `target_link_libraries`.

Fix the update that commit 73337cb383 (LINK_LIBRARIES: Evaluate
separately for linking and usage requirements, 2022-03-22,
v3.24.0-rc1~404^2~2) made to `AddObjectEntries`.

Fixes: #26642

Source/cmGeneratorTarget_Sources.cxx

@@ -51,7 +51,7 @@ void AddObjectEntries(cmGeneratorTarget const* headTarget,
                       EvaluatedTargetPropertyEntries& entries)
 {
   if (cmLinkImplementationLibraries const* impl =
-        headTarget->GetLinkImplementationLibraries(config, UseTo::Compile)) {
+        headTarget->GetLinkImplementationLibraries(config, UseTo::Link)) {
     entries.HadContextSensitiveCondition = impl->HadContextSensitiveCondition;
     for (cmLinkImplItem const& lib : impl->Libraries) {
       if (lib.Target &&

Tests/CMakeCommands/target_link_libraries/CMakeLists.txt

@@ -157,7 +157,7 @@ cmake_policy(POP)
 # Test $<COMPILE_ONLY:> genex.
 cmake_policy(SET CMP0099 NEW)
 add_library(dont_link_too SHARED compile_only.cpp)
-target_compile_definitions(dont_link_too PUBLIC USE_EXAMPLE)
+target_compile_definitions(dont_link_too PUBLIC USE_EXAMPLE PRIVATE HAVE_FUNCTION)
 target_link_options(dont_link_too INTERFACE invalid_link_option)
 target_link_libraries(dont_link_too INTERFACE invalid_link_library)
 
@@ -168,3 +168,15 @@ add_library(uses_compile_only_genex_static STATIC compile_only.cpp)
 target_link_libraries(uses_compile_only_genex_static PRIVATE $<COMPILE_ONLY:dont_link_too>)
 add_executable(uses_via_static_linking main.cxx)
 target_link_libraries(uses_via_static_linking PRIVATE uses_compile_only_genex_static)
+
+add_library(uses_compile_only_genex_obj SHARED compile_only.cpp)
+target_compile_definitions(uses_compile_only_genex_obj PRIVATE HAVE_FUNCTION)
+target_link_libraries(uses_compile_only_genex_obj PRIVATE $<COMPILE_ONLY:dont_link_too>)
+
+cmake_policy(SET CMP0131 NEW)
+add_library(only_link_too OBJECT link_only.cpp)
+target_compile_options(only_link_too INTERFACE INVALID_COMPILER_FLAG_ARRRRGH)
+
+add_executable(uses_link_only_genex_obj compile_only.cpp)
+target_compile_definitions(uses_link_only_genex_obj PUBLIC USE_EXAMPLE)
+target_link_libraries(uses_link_only_genex_obj PRIVATE $<LINK_ONLY:only_link_too>)

Tests/CMakeCommands/target_link_libraries/compile_only.cpp

@@ -3,6 +3,13 @@
 #  error "Missing propagated define"
 #endif
 
+#ifdef HAVE_FUNCTION
+int non_duplicate_function()
+{
+  return 42;
+}
+#endif
+
 // Solaris needs non-empty content so ensure
 // we have at least one symbol
 int Solaris_requires_a_symbol_here = 0;

Tests/CMakeCommands/target_link_libraries/link_only.cpp

@@ -0,0 +1,4 @@
+int main()
+{
+  return 0;
+}