Genex: $<TARGET_PROPERTY> strip emtpy list elements for predefined properties

Fixes: #20951

Source/cmGeneratorExpressionNode.cxx

@@ -1476,8 +1476,9 @@ static const struct TargetPropertyNode : public cmGeneratorExpressionNode
     }
 
     if (isInterfaceProperty) {
-      return target->EvaluateInterfaceProperty(propertyName, context,
-                                               dagCheckerParent);
+      return cmGeneratorExpression::StripEmptyListElements(
+        target->EvaluateInterfaceProperty(propertyName, context,
+                                          dagCheckerParent));
     }
 
     cmGeneratorExpressionDAGChecker dagChecker(
@@ -1563,8 +1564,9 @@ static const struct TargetPropertyNode : public cmGeneratorExpressionNode
     }
 
     if (!interfacePropertyName.empty()) {
-      result = this->EvaluateDependentExpression(result, context->LG, context,
-                                                 target, &dagChecker, target);
+      result = cmGeneratorExpression::StripEmptyListElements(
+        this->EvaluateDependentExpression(result, context->LG, context, target,
+                                          &dagChecker, target));
       std::string linkedTargetsContent = getLinkedTargetsContent(
         target, interfacePropertyName, context, &dagChecker);
       if (!linkedTargetsContent.empty()) {

Tests/GeneratorExpression/check-part3.cmake

@@ -9,11 +9,11 @@ check(test_version_equal_1 "0")
 check(test_version_equal_2 "1")
 
 if(config AND NOT config STREQUAL NoConfig)
-  if(NOT "${test_imported_includes}" MATCHES "^;*/imported[12]/include/with space;*$")
+  if(NOT "${test_imported_includes}" MATCHES "^[^;]*/imported[12]/include/with space$")
     message(SEND_ERROR "test_imported_includes is not correct: ${test_imported_includes}")
   endif()
 else()
-  if(NOT "${test_imported_includes}" MATCHES "^;;$")
+  if(NOT "${test_imported_includes}" MATCHES "^$")
     message(SEND_ERROR "test_imported_includes is not an empty list: ${test_imported_includes}")
   endif()
 endif()

Tests/RunCMake/GeneratorExpression/TARGET_PROPERTY-INCLUDE_DIRECTORIES-check.cmake

@@ -0,0 +1,17 @@
+file(READ "${RunCMake_TEST_BINARY_DIR}/out.txt" content)
+
+unset(RunCMake_TEST_FAILED)
+
+if (NOT content MATCHES "(INCLUDES1:${RunCMake_TEST_SOURCE_DIR}/include)")
+  string(APPEND RunCMake_TEST_FAILED "wrong content for INCLUDES1: \"${CMAKE_MATCH_1}\"\n")
+endif()
+
+if (NOT content MATCHES "(INCLUDES2:><)")
+  string(APPEND RunCMake_TEST_FAILED "wrong content for INCLUDES2: \"${CMAKE_MATCH_1}\"\n")
+endif()
+if (NOT content MATCHES "(INCLUDES3:><)")
+  string(APPEND RunCMake_TEST_FAILED "wrong content for INCLUDES3: \"${CMAKE_MATCH_1}\"\n")
+endif()
+if (NOT content MATCHES "(CUSTOM:>;;<)")
+  string(APPEND RunCMake_TEST_FAILED "wrong content for CUSTOM: \"${CMAKE_MATCH_1}\"\n")
+endif()

Tests/RunCMake/GeneratorExpression/TARGET_PROPERTY-INCLUDE_DIRECTORIES.cmake

@@ -14,5 +14,10 @@ target_include_directories(foo3 PUBLIC $<TARGET_PROPERTY:foo2,INCLUDE_DIRECTORIE
 add_library(foo4 STATIC empty.c)
 target_include_directories(foo4 PUBLIC $<TARGET_PROPERTY:foo3,INCLUDE_DIRECTORIES>)
 
+add_library (foo5 SHARED empty.c)
+set_property(TARGET foo5 PROPERTY INCLUDE_DIRECTORIES "$<$<COMPILE_LANGUAGE:CUDA>:/include/CUDA>" "$<$<COMPILE_LANGUAGE:Fortran>:/include/Fortran>")
+set_property(TARGET foo5 PROPERTY INTERFACE_INCLUDE_DIRECTORIES "$<$<COMPILE_LANGUAGE:CUDA>:/include/CUDA>" "$<$<COMPILE_LANGUAGE:Fortran>:/include/Fortran>")
+set_property(TARGET foo5 PROPERTY CUSTOM ";;")
+
 # Evaluate a genex that looks up INCLUDE_DIRECTORIES on multiple targets.
-file(GENERATE OUTPUT out.txt CONTENT "$<TARGET_PROPERTY:foo4,INCLUDE_DIRECTORIES>")
+file(GENERATE OUTPUT out.txt CONTENT "INCLUDES1:$<TARGET_PROPERTY:foo4,INCLUDE_DIRECTORIES>\nINCLUDES2:>$<TARGET_PROPERTY:foo5,INTERFACE_INCLUDE_DIRECTORIES><\nINCLUDES3:>$<TARGET_PROPERTY:foo5,INCLUDE_DIRECTORIES><\nCUSTOM:>$<TARGET_PROPERTY:foo5,CUSTOM><\n")