add_custom_command: Properly recognize if sources depend on config

Fixes: #21349

2 files changed, 24 insertions, 6 deletions

diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index bdea9fa..3560739 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -3098,12 +3098,17 @@ void cmTargetTraceDependencies::CheckCustomCommand(cmCustomCommand const& cc)
     }
 
     // Check for target references in generator expressions.
-    for (std::string const& cl : cCmdLine) {
-      const std::unique_ptr<cmCompiledGeneratorExpression> cge = ge.Parse(cl);
-      cge->SetQuiet(true);
-      cge->Evaluate(this->GeneratorTarget->GetLocalGenerator(), "");
-      std::set<cmGeneratorTarget*> geTargets = cge->GetTargets();
-      targets.insert(geTargets.begin(), geTargets.end());
+    std::vector<std::string> const& configs =
+      this->Makefile->GetGeneratorConfigs(cmMakefile::IncludeEmptyConfig);
+    for (std::string const& c : configs) {
+      for (std::string const& cl : cCmdLine) {
+        const std::unique_ptr<cmCompiledGeneratorExpression> cge =
+          ge.Parse(cl);
+        cge->SetQuiet(true);
+        cge->Evaluate(this->GeneratorTarget->GetLocalGenerator(), c);
+        std::set<cmGeneratorTarget*> geTargets = cge->GetTargets();
+        targets.insert(geTargets.begin(), geTargets.end());
+      }
     }
   }
 
diff --git a/Tests/ConfigSources/CMakeLists.txt b/Tests/ConfigSources/CMakeLists.txt
index 7b1a312..1db00cc 100644
--- a/Tests/ConfigSources/CMakeLists.txt
+++ b/Tests/ConfigSources/CMakeLists.txt
@@ -91,3 +91,16 @@ target_compile_definitions(ObjLibFromGeneratedSources PRIVATE OBJ_SHARED)
 target_sources(ObjLibFromGeneratedSources PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/config_$<CONFIG>.cpp)
 add_library(SharedLibFromObjLibFromGeneratedSources SHARED shared.cpp)
 target_link_libraries(SharedLibFromObjLibFromGeneratedSources PRIVATE ObjLibFromGeneratedSources)
+
+
+# ---------------------------------------------------------------------------
+# Make sure that additional build-events do not confuse CMake when using generated files.
+add_library(SharedLibFromGeneratedSources SHARED)
+set_property(TARGET SharedLibFromGeneratedSources PROPERTY POSITION_INDEPENDENT_CODE 1)
+target_sources(SharedLibFromGeneratedSources PRIVATE
+  shared.cpp
+  ${CMAKE_CURRENT_BINARY_DIR}/config_$<CONFIG>.cpp
+  )
+add_custom_command(TARGET SharedLibFromGeneratedSources POST_BUILD
+  COMMAND "${CMAKE_COMMAND}" "-E" "echo" "$<TARGET_FILE:SharedLibFromGeneratedSources>"
+  )