WIP: Change the build system to enable building with Qt 6

This was built with:
-DQT_MAJOR_VERSION=6 \
-DEXCLUDE_DEPRECATED_BEFORE_AND_AT=5.90.0 \
-DKF_DISABLE_DEPRECATED_BEFORE_AND_AT=0x055a00

Move the include(KDEInstallDirs) call before the first find_package(Qt*,
the former is what auto-detects the Qt version, and defaults to 5. This is
needed to be able to build against Qt5 by default.

All unit tests still pass.

12 files changed, 71 insertions, 60 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9fe55a63..d880c52a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,25 +10,6 @@ feature_summary(WHAT REQUIRED_PACKAGES_NOT_FOUND FATAL_ON_MISSING_REQUIRED_PACKA
 
 set(CMAKE_MODULE_PATH ${ECM_MODULE_PATH})
 
-set(REQUIRED_QT_VERSION 5.15.2)
-
-find_package(Qt5 ${REQUIRED_QT_VERSION} CONFIG REQUIRED Xml)
-option(KCONFIG_USE_GUI "Build components using Qt5Gui" ON)
-if(KCONFIG_USE_GUI)
-    find_package(Qt5 ${REQUIRED_QT_VERSION} CONFIG REQUIRED Gui)
-endif()
-find_package(Qt5 ${REQUIRED_QT_VERSION} OPTIONAL_COMPONENTS Qml)
-
-if (NOT ANDROID)
-    option(KCONFIG_USE_DBUS "Build components using Qt5DBus" ON)
-    if(KCONFIG_USE_DBUS)
-        find_package(Qt5 ${REQUIRED_QT_VERSION} CONFIG REQUIRED DBus)
-    endif()
-else()
-    set(KCONFIG_USE_DBUS Off)
-endif()
-
-
 include(KDEInstallDirs)
 include(KDEFrameworkCompilerSettings NO_POLICY_SCOPE)
 include(KDECMakeSettings)
@@ -42,6 +23,24 @@ include(ECMPoQmTools)
 include(ECMAddQch)
 include(ECMQtDeclareLoggingCategory)
 
+set(REQUIRED_QT_VERSION 5.15.2)
+
+find_package(Qt${QT_MAJOR_VERSION} ${REQUIRED_QT_VERSION} CONFIG REQUIRED Xml)
+option(KCONFIG_USE_GUI "Build components using Qt${QT_MAJOR_VERSION}Gui" ON)
+if(KCONFIG_USE_GUI)
+    find_package(Qt${QT_MAJOR_VERSION} ${REQUIRED_QT_VERSION} CONFIG REQUIRED Gui)
+endif()
+find_package(Qt${QT_MAJOR_VERSION} ${REQUIRED_QT_VERSION} OPTIONAL_COMPONENTS Qml)
+
+if (NOT ANDROID)
+    option(KCONFIG_USE_DBUS "Build components using Qt${QT_MAJOR_VERSION}DBus" ON)
+    if(KCONFIG_USE_DBUS)
+        find_package(Qt${QT_MAJOR_VERSION} ${REQUIRED_QT_VERSION} CONFIG REQUIRED DBus)
+    endif()
+else()
+    set(KCONFIG_USE_DBUS Off)
+endif()
+
 set(EXCLUDE_DEPRECATED_BEFORE_AND_AT 0 CACHE STRING "Control the range of deprecated API excluded from the build [default=0].")
 
 option(BUILD_QCH "Build API documentation in QCH format (for e.g. Qt Assistant, Qt Creator & KDevelop)" OFF)
@@ -98,7 +97,7 @@ install(EXPORT KF5ConfigCompilerTargets DESTINATION "${CMAKECONFIG_INSTALL_DIR}"
         FILE KF5ConfigCompilerTargets.cmake NAMESPACE KF5:: COMPONENT Devel)
 
 install(FILES ${CMAKE_CURRENT_BINARY_DIR}/kconfig_version.h
-        DESTINATION ${KDE_INSTALL_INCLUDEDIR_KF5} COMPONENT Devel )
+        DESTINATION ${KDE_INSTALL_INCLUDEDIR_KF} COMPONENT Devel )
 
 
 feature_summary(WHAT ALL FATAL_ON_MISSING_REQUIRED_PACKAGES)
diff --git a/KF5ConfigConfig.cmake.in b/KF5ConfigConfig.cmake.in
index d24ae2ba..9b696ceb 100644
--- a/KF5ConfigConfig.cmake.in
+++ b/KF5ConfigConfig.cmake.in
@@ -6,10 +6,10 @@ include("${CMAKE_CURRENT_LIST_DIR}/KF5ConfigTargets.cmake")
 @PACKAGE_INCLUDE_QCHTARGETS@
 
 include(CMakeFindDependencyMacro)
-find_dependency(Qt5Xml "@REQUIRED_QT_VERSION@")
+find_dependency(Qt@QT_MAJOR_VERSION@Xml @REQUIRED_QT_VERSION@)
 
 if(@KCONFIG_USE_DBUS@)
-    find_dependency(Qt5DBus "@REQUIRED_QT_VERSION@")
+    find_dependency(Qt@QT_MAJOR_VERSION@DBus "@REQUIRED_QT_VERSION@")
 endif()
 
 if(CMAKE_CROSSCOMPILING AND KF5_HOST_TOOLING)
diff --git a/KF5ConfigMacros.cmake b/KF5ConfigMacros.cmake
index 3ceaf17c..80c947d8 100644
--- a/KF5ConfigMacros.cmake
+++ b/KF5ConfigMacros.cmake
@@ -111,7 +111,7 @@ function (KCONFIG_ADD_KCFG_FILES _target_or_source_var)
 
        if(ARG_GENERATE_MOC)
           list(APPEND sources ${_moc_FILE})
-          qt5_generate_moc(${_header_FILE} ${_moc_FILE})
+          qt_generate_moc(${_header_FILE} ${_moc_FILE})
           set_property(SOURCE ${_src_FILE} APPEND PROPERTY OBJECT_DEPENDS ${_moc_FILE} )
        endif()
 
diff --git a/autotests/CMakeLists.txt b/autotests/CMakeLists.txt
index cae4c0b1..a7e37e5a 100644
--- a/autotests/CMakeLists.txt
+++ b/autotests/CMakeLists.txt
@@ -1,14 +1,14 @@
 include(ECMAddTests)
 
-find_package(Qt5Test ${REQUIRED_QT_VERSION} CONFIG QUIET)
-find_package(Qt5Concurrent ${REQUIRED_QT_VERSION} CONFIG QUIET)
+find_package(Qt${QT_MAJOR_VERSION}Test ${REQUIRED_QT_VERSION} CONFIG QUIET)
+find_package(Qt${QT_MAJOR_VERSION}Concurrent ${REQUIRED_QT_VERSION} CONFIG QUIET)
 
-if(NOT Qt5Test_FOUND)
+if(NOT Qt${QT_MAJOR_VERSION}Test_FOUND)
     message(STATUS "Qt5Test not found, autotests will not be built.")
     return()
 endif()
 
-if(NOT Qt5Concurrent_FOUND)
+if(NOT Qt${QT_MAJOR_VERSION}Concurrent_FOUND)
     message(STATUS "Qt5Concurrent not found, autotests will not be built.")
     return()
 endif()
@@ -18,7 +18,7 @@ ecm_add_test(
   kentrymaptest.cpp
   ../src/core/kconfigdata.cpp
   TEST_NAME kentrymaptest
-  LINK_LIBRARIES Qt5::Test
+  LINK_LIBRARIES Qt${QT_MAJOR_VERSION}::Test
 )
 target_include_directories(kentrymaptest PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/../src/core)
 
@@ -27,17 +27,17 @@ ecm_add_test(
   test_kconfigutils.cpp
   ../src/kconf_update/kconfigutils.cpp
   TEST_NAME test_kconfigutils
-  LINK_LIBRARIES KF5::ConfigCore Qt5::Test
+  LINK_LIBRARIES KF5::ConfigCore Qt${QT_MAJOR_VERSION}::Test
 )
 target_include_directories(test_kconfigutils PRIVATE ../src/kconf_update)
 
 qt_add_resources(sharedconfigresources sharedconfigresources.qrc)
 
-ecm_add_test(ksharedconfigtest.cpp ${sharedconfigresources} TEST_NAME kconfigcore-ksharedconfigtest LINK_LIBRARIES KF5::ConfigCore Qt5::Test Qt5::Concurrent)
+ecm_add_test(ksharedconfigtest.cpp ${sharedconfigresources} TEST_NAME kconfigcore-ksharedconfigtest LINK_LIBRARIES KF5::ConfigCore Qt${QT_MAJOR_VERSION}::Test Qt${QT_MAJOR_VERSION}::Concurrent)
 
 # test for fallback to :/kconfig/xxxx config resource
 qt_add_resources(fallbackconfigresources fallbackconfigresources.qrc)
-ecm_add_test(fallbackconfigresourcestest.cpp ${fallbackconfigresources} TEST_NAME kconfigcore-fallbackconfigresourcestest LINK_LIBRARIES KF5::ConfigCore Qt5::Test Qt5::Concurrent)
+ecm_add_test(fallbackconfigresourcestest.cpp ${fallbackconfigresources} TEST_NAME kconfigcore-fallbackconfigresourcestest LINK_LIBRARIES KF5::ConfigCore Qt${QT_MAJOR_VERSION}::Test Qt${QT_MAJOR_VERSION}::Concurrent)
 
 ecm_add_tests(
    kconfignokdehometest.cpp
@@ -46,19 +46,19 @@ ecm_add_tests(
    test_kconf_update.cpp
    ksharedconfig_in_global_object.cpp
    NAME_PREFIX kconfigcore-
-   LINK_LIBRARIES KF5::ConfigCore Qt5::Test Qt5::Concurrent
+   LINK_LIBRARIES KF5::ConfigCore Qt${QT_MAJOR_VERSION}::Test Qt${QT_MAJOR_VERSION}::Concurrent
 )
 
 target_include_directories(test_kconf_update PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/../src/kconf_update)
 
-if(TARGET Qt5::Gui)
+if(TARGET Qt${QT_MAJOR_VERSION}::Gui)
 ecm_add_tests(
    kconfigguitest.cpp
    kconfigloadertest.cpp
    kconfigskeletontest.cpp
    kstandardshortcuttest.cpp
    NAME_PREFIX kconfiggui-
-   LINK_LIBRARIES KF5::ConfigGui Qt5::Test
+   LINK_LIBRARIES KF5::ConfigGui Qt${QT_MAJOR_VERSION}::Test
 )
 
 # These tests do a global cleanup of ~/.qttest, so they can't run in parallel
diff --git a/autotests/kconfig_compiler/CMakeLists.txt b/autotests/kconfig_compiler/CMakeLists.txt
index 4caa17af..5cbf2e44 100644
--- a/autotests/kconfig_compiler/CMakeLists.txt
+++ b/autotests/kconfig_compiler/CMakeLists.txt
@@ -177,7 +177,7 @@ set(test_state_config_SRCS test_state_config_main.cpp)
 gen_kcfg_test_source(test_state_config test_state_config_SRCS GENERATE_MOC)
 
 ecm_add_test(TEST_NAME test_state_config ${test_state_config_SRCS})
-target_link_libraries(test_state_config KF5::ConfigGui Qt5::Test)
+target_link_libraries(test_state_config KF5::ConfigGui Qt${QT_MAJOR_VERSION}::Test)
 
 ########### next target ###############
 
@@ -234,7 +234,7 @@ gen_kcfg_test_source(signals_test_no_singleton_dpointer kconfigcompiler_test_sig
 
 ecm_add_test(${kconfigcompiler_test_signals_SRCS}
     TEST_NAME kconfigcompiler-signals-test
-    LINK_LIBRARIES Qt5::Test KF5::ConfigGui
+    LINK_LIBRARIES Qt${QT_MAJOR_VERSION}::Test KF5::ConfigGui
 )
 
 ########### next target ###############
@@ -261,7 +261,7 @@ ecm_add_test(${test_param_minmax_SRCS}
 
 ecm_add_test(kconfigcompiler_test.cpp
     TEST_NAME kconfigcompiler-basic-test
-    LINK_LIBRARIES Qt5::Test
+    LINK_LIBRARIES Qt${QT_MAJOR_VERSION}::Test
 )
 
 
diff --git a/autotests/kconfigtest.cpp b/autotests/kconfigtest.cpp
index 4657ea8d..95a87584 100644
--- a/autotests/kconfigtest.cpp
+++ b/autotests/kconfigtest.cpp
@@ -1974,18 +1974,30 @@ void KConfigTest::testXdgListEntry()
 void KConfigTest::testThreads()
 {
     QThreadPool::globalInstance()->setMaxThreadCount(6);
-    QList<QFuture<void>> futures;
     // Run in parallel some tests that work on different config files,
     // otherwise unexpected things might indeed happen.
-    futures << QtConcurrent::run(this, &KConfigTest::testAddConfigSources);
-    futures << QtConcurrent::run(this, &KConfigTest::testSimple);
-    futures << QtConcurrent::run(this, &KConfigTest::testDefaults);
-    futures << QtConcurrent::run(this, &KConfigTest::testSharedConfig);
-    futures << QtConcurrent::run(this, &KConfigTest::testSharedConfig);
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    const QList<QFuture<void>> futures = {
+        QtConcurrent::run(&KConfigTest::testAddConfigSources, this),
+        QtConcurrent::run(&KConfigTest::testSimple, this),
+        QtConcurrent::run(&KConfigTest::testDefaults, this),
+        QtConcurrent::run(&KConfigTest::testSharedConfig, this),
+        QtConcurrent::run(&KConfigTest::testSharedConfig, this),
+    };
+#else
+    const QList<QFuture<void>> futures = {
+        QtConcurrent::run(this, &KConfigTest::testAddConfigSources),
+        QtConcurrent::run(this, &KConfigTest::testSimple),
+        QtConcurrent::run(this, &KConfigTest::testDefaults),
+        QtConcurrent::run(this, &KConfigTest::testSharedConfig),
+        QtConcurrent::run(this, &KConfigTest::testSharedConfig),
+    };
+#endif
+
     // QEXPECT_FAIL triggers race conditions, it should be fixed to use QThreadStorage...
     // futures << QtConcurrent::run(this, &KConfigTest::testDeleteWhenLocalized);
     // futures << QtConcurrent::run(this, &KConfigTest::testEntryMap);
-    for (QFuture<void> f : std::as_const(futures)) {
+    for (QFuture<void> f : futures) {
         f.waitForFinished();
     }
 }
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 89fe7284..715890e0 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,8 +1,8 @@
 add_subdirectory(core)
-if(TARGET Qt5::Gui)
+if(TARGET Qt${QT_MAJOR_VERSION}::Gui)
     add_subdirectory(gui)
 endif()
-if(TARGET Qt5::Qml)
+if(TARGET Qt${QT_MAJOR_VERSION}::Qml)
     add_subdirectory(qml)
 endif()
 add_subdirectory(kconfig_compiler)
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index c91dd040..2b5e949c 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -41,12 +41,12 @@ target_compile_definitions(KF5ConfigCore
         KCONF_UPDATE_INSTALL_LOCATION="${KDE_INSTALL_FULL_LIBEXECDIR_KF5}/$<TARGET_FILE_NAME:KF5::kconf_update>"
 )
 
-target_include_directories(KF5ConfigCore INTERFACE "$<INSTALL_INTERFACE:${KDE_INSTALL_INCLUDEDIR_KF5}/KConfigCore>")
+target_include_directories(KF5ConfigCore INTERFACE "$<INSTALL_INTERFACE:${KDE_INSTALL_INCLUDEDIR_KF}/KConfigCore>")
 
-target_link_libraries(KF5ConfigCore PUBLIC Qt5::Core)
+target_link_libraries(KF5ConfigCore PUBLIC Qt${QT_MAJOR_VERSION}::Core)
 
 if(KCONFIG_USE_DBUS)
-    target_link_libraries(KF5ConfigCore PRIVATE Qt5::DBus)
+    target_link_libraries(KF5ConfigCore PRIVATE Qt${QT_MAJOR_VERSION}::DBus)
 endif()
 
 set_target_properties(KF5ConfigCore PROPERTIES VERSION   ${KCONFIG_VERSION}
@@ -98,7 +98,7 @@ install(TARGETS KF5ConfigCore EXPORT KF5ConfigTargets ${KF5_INSTALL_TARGETS_DEFA
 install(FILES
   ${CMAKE_CURRENT_BINARY_DIR}/kconfigcore_export.h
   ${KConfigCore_HEADERS}
-  DESTINATION ${KDE_INSTALL_INCLUDEDIR_KF5}/KConfigCore COMPONENT Devel
+  DESTINATION ${KDE_INSTALL_INCLUDEDIR_KF}/KConfigCore COMPONENT Devel
 )
 
 # make available to ecm_add_qch in parent folder
@@ -106,5 +106,5 @@ set(KConfigCore_APIDOX_SRCS ${KConfigCore_HEADERS} PARENT_SCOPE)
 set(KConfigCore_APIDOX_INCLUDE_DIRS ${CMAKE_CURRENT_BINARY_DIR} PARENT_SCOPE)
 
 include(ECMGeneratePriFile)
-ecm_generate_pri_file(BASE_NAME KConfigCore LIB_NAME KF5ConfigCore DEPS "core" FILENAME_VAR PRI_FILENAME INCLUDE_INSTALL_DIR ${KDE_INSTALL_INCLUDEDIR_KF5}/KConfigCore)
+ecm_generate_pri_file(BASE_NAME KConfigCore LIB_NAME KF5ConfigCore DEPS "core" FILENAME_VAR PRI_FILENAME INCLUDE_INSTALL_DIR ${KDE_INSTALL_INCLUDEDIR_KF}/KConfigCore)
 install(FILES ${PRI_FILENAME} DESTINATION ${ECM_MKSPECS_INSTALL_DIR})
diff --git a/src/gui/CMakeLists.txt b/src/gui/CMakeLists.txt
index 9dad629a..4d5512d1 100644
--- a/src/gui/CMakeLists.txt
+++ b/src/gui/CMakeLists.txt
@@ -21,9 +21,9 @@ ecm_generate_export_header(KF5ConfigGui
     EXCLUDE_DEPRECATED_BEFORE_AND_AT ${EXCLUDE_DEPRECATED_BEFORE_AND_AT}
 )
 
-target_include_directories(KF5ConfigGui INTERFACE "$<INSTALL_INTERFACE:${KDE_INSTALL_INCLUDEDIR_KF5}/KConfigGui>")
+target_include_directories(KF5ConfigGui INTERFACE "$<INSTALL_INTERFACE:${KDE_INSTALL_INCLUDEDIR_KF}/KConfigGui>")
 
-target_link_libraries(KF5ConfigGui PUBLIC Qt5::Gui Qt5::Xml KF5::ConfigCore)
+target_link_libraries(KF5ConfigGui PUBLIC Qt${QT_MAJOR_VERSION}::Gui Qt${QT_MAJOR_VERSION}::Xml KF5::ConfigCore)
 
 set_target_properties(KF5ConfigGui PROPERTIES VERSION   ${KCONFIG_VERSION}
                                               SOVERSION ${KCONFIG_SOVERSION}
@@ -68,7 +68,7 @@ install(TARGETS KF5ConfigGui EXPORT KF5ConfigTargets ${KF5_INSTALL_TARGETS_DEFAU
 install(FILES
   ${CMAKE_CURRENT_BINARY_DIR}/kconfiggui_export.h
   ${KConfigGui_HEADERS}
-  DESTINATION ${KDE_INSTALL_INCLUDEDIR_KF5}/KConfigGui COMPONENT Devel
+  DESTINATION ${KDE_INSTALL_INCLUDEDIR_KF}/KConfigGui COMPONENT Devel
 )
 
 # make available to ecm_add_qch in parent folder
@@ -76,5 +76,5 @@ set(KConfigGui_APIDOX_SRCS ${KConfigGui_HEADERS} PARENT_SCOPE)
 set(KConfigGui_APIDOX_INCLUDE_DIRS ${CMAKE_CURRENT_BINARY_DIR} PARENT_SCOPE)
 
 include(ECMGeneratePriFile)
-ecm_generate_pri_file(BASE_NAME KConfigGui LIB_NAME KF5ConfigGui DEPS "gui xml KConfigCore" FILENAME_VAR PRI_FILENAME INCLUDE_INSTALL_DIR ${KDE_INSTALL_INCLUDEDIR_KF5}/KConfigGui)
+ecm_generate_pri_file(BASE_NAME KConfigGui LIB_NAME KF5ConfigGui DEPS "gui xml KConfigCore" FILENAME_VAR PRI_FILENAME INCLUDE_INSTALL_DIR ${KDE_INSTALL_INCLUDEDIR_KF}/KConfigGui)
 install(FILES ${PRI_FILENAME} DESTINATION ${ECM_MKSPECS_INSTALL_DIR})
diff --git a/src/kconf_update/CMakeLists.txt b/src/kconf_update/CMakeLists.txt
index 40fb4ccb..8c23b358 100644
--- a/src/kconf_update/CMakeLists.txt
+++ b/src/kconf_update/CMakeLists.txt
@@ -15,7 +15,7 @@ ecm_qt_declare_logging_category(kconf_update
     EXPORT KCONFIG
 )
 
-target_link_libraries(kconf_update Qt5::Core KF5::ConfigCore)
+target_link_libraries(kconf_update Qt${QT_MAJOR_VERSION}::Core KF5::ConfigCore)
 include(ECMMarkNonGuiExecutable)
 ecm_mark_nongui_executable(kconf_update)
 
diff --git a/src/kconfig_compiler/CMakeLists.txt b/src/kconfig_compiler/CMakeLists.txt
index 0e11ee58..a475b511 100644
--- a/src/kconfig_compiler/CMakeLists.txt
+++ b/src/kconfig_compiler/CMakeLists.txt
@@ -21,7 +21,7 @@ set_target_properties(kconfig_compiler PROPERTIES
     OUTPUT_NAME "kconfig_compiler_kf5"
 )
 
-target_link_libraries(kconfig_compiler Qt5::Xml)
+target_link_libraries(kconfig_compiler Qt${QT_MAJOR_VERSION}::Xml)
 
 ecm_mark_nongui_executable(kconfig_compiler)
 
diff --git a/src/qml/CMakeLists.txt b/src/qml/CMakeLists.txt
index 1cdae88a..17f90ad0 100644
--- a/src/qml/CMakeLists.txt
+++ b/src/qml/CMakeLists.txt
@@ -16,7 +16,7 @@ ecm_generate_export_header(KF5ConfigQml
 target_link_libraries(KF5ConfigQml
   PUBLIC
     KF5::ConfigCore # KCoreConfigSkeleton, in ConfigPropertyMap
-    Qt5::Qml
+    Qt${QT_MAJOR_VERSION}::Qml
 )
 set_target_properties(KF5ConfigQml PROPERTIES VERSION     ${KCONFIG_VERSION}
                                               SOVERSION   ${KCONFIG_SOVERSION}
@@ -29,11 +29,11 @@ ecm_generate_headers(KConfigQml_HEADERS
 
     REQUIRED_HEADERS KConfigQml_HEADERS
 )
-target_include_directories(KF5ConfigQml INTERFACE "$<INSTALL_INTERFACE:${KDE_INSTALL_INCLUDEDIR_KF5}/KConfigQml>")
+target_include_directories(KF5ConfigQml INTERFACE "$<INSTALL_INTERFACE:${KDE_INSTALL_INCLUDEDIR_KF}/KConfigQml>")
 
 install(TARGETS KF5ConfigQml EXPORT KF5ConfigTargets ${KF5_INSTALL_TARGETS_DEFAULT_ARGS})
 install(FILES
   ${CMAKE_CURRENT_BINARY_DIR}/kconfigqml_export.h
   ${KConfigQml_HEADERS}
-  DESTINATION ${KDE_INSTALL_INCLUDEDIR_KF5}/KConfigQml COMPONENT Devel
+  DESTINATION ${KDE_INSTALL_INCLUDEDIR_KF}/KConfigQml COMPONENT Devel
 )