In order to migrate to Qt6 all options for KF6 were added:

a) using a system provided KF6
b) downloading and compiling KF6
c) using the vendored-in re-creation of the functionality

The behaviour for both Qt5 and Qt6 is steered with the same two variables which were renamed to become version agnostic:
a) BUILD_WITH_KF=ON BUILD_KF=OFF
b) BUILD_WITH_KF=ON BUILD_KF=ON
c) BUILD_WITH_KF=OFF

The version is automatically derived from the chosen Qt major version.

.github/workflows/windows-build.yml

@@ -456,7 +456,7 @@ jobs:
             -DCMAKE_PREFIX_PATH=/ucrt64 \
             -DQt6_DIR=/ucrt64/lib/cmake/Qt6 \
             -DQT_VERSION_MAJOR=6 \
-            -DBUILD_WITH_KF5=OFF \
+            -DBUILD_WITH_KF=OFF \
             -DPACKAGE_TESTS=OFF \
             -DCMAKE_POLICY_DEFAULT_CMP0077=NEW \
             -DCMAKE_POLICY_VERSION_MINIMUM=3.5 \

CMakeLists.txt

@@ -48,19 +48,11 @@ endif()
 # INTERFACE_QT_MAJOR_VERSION mismatch at generate time.
 set(QT_DEFAULT_MAJOR_VERSION ${QT_VERSION_MAJOR} CACHE STRING "Qt version to use (5 or 6)" FORCE)
 
-# Add sub directories
-option(PACKAGE_TESTS "Build the tests" ON)
-if(PACKAGE_TESTS)
-    message("Add sub directory tests")
-    add_subdirectory(tests)
-endif()
-
 include(cmake/paths_compilation_installation.cmake)
 include(cmake/start_options.cmake)
 include(cmake/developer_options.cmake)
 include(cmake/git_update_submodules.cmake)
 include(cmake/git_last_commit_sha.cmake)
-include(cmake/fetch_kdeaddons.cmake)
 include(cmake/fetch_singleapplication.cmake)
 include(cmake/fetch_pugixml.cmake)
 include(cmake/qet_compilation_vars.cmake)
@@ -100,25 +92,19 @@ endif()
 
 set(CMAKE_AUTOUIC_SEARCH_PATHS ${QET_DIR}/sources/ui)
 
-# The default build only compiles the tracked .ts files to .qm (lrelease).
-# Refreshing the .ts from the sources (lupdate) is a developer action behind
-# the explicit "update_translations" target below: running lupdate on every
-# build rewrote tracked files as a side effect, and under high parallelism
-# lupdate rewriting a .ts while lrelease read the same file made the build
-# fail with "Premature end of document".
-set_source_files_properties(${TS_FILES} PROPERTIES OUTPUT_LOCATION "${QET_DIR}/lang")
 if(QT_VERSION_MAJOR EQUAL 6)
-    qt6_add_translation(QM_FILES ${TS_FILES})
+    set(KF_MAJOR_VERSION 6)
 else()
-    qt5_add_translation(QM_FILES ${TS_FILES})
+    set(KF_MAJOR_VERSION 5)
 endif()
+include(cmake/fetch_kdeaddons.cmake)
 
-add_custom_target(update_translations
-    COMMAND $<TARGET_FILE:Qt${QT_VERSION_MAJOR}::lupdate> ${CMAKE_SOURCE_DIR}/sources -ts ${TS_FILES}
-    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
-    COMMENT "Updating .ts files from sources/ (lupdate) - developer target, run explicitly"
-    VERBATIM
-)
+# Add sub directories
+option(PACKAGE_TESTS "Build the tests" ON)
+if(PACKAGE_TESTS)
+    message("Add sub directory tests")
+    add_subdirectory(tests)
+endif()
 
 # als laatse
 include(cmake/define_definitions.cmake)
@@ -145,6 +131,36 @@ else()
     )
 endif()
 
+# The default build only compiles the tracked .ts files to .qm (lrelease).
+# Refreshing the .ts from the sources (lupdate) is a developer action behind
+# the explicit "update_translations" target below: running lupdate on every
+# build rewrote tracked files as a side effect, and under high parallelism
+# lupdate rewriting a .ts while lrelease read the same file made the build
+# fail with "Premature end of document".
+if(QT_VERSION_MAJOR EQUAL 6)
+    qt_add_lrelease(
+    	TARGETS ${PROJECT_NAME} 
+    	TS_FILES ${TS_FILES}
+    	QM_OUTPUT_DIRECTORY "${QET_DIR}/lang"
+    	QM_FILES_OUTPUT_VARIABLE QM_FILES 
+    )
+    qt_add_lupdate(
+    	TS_FILES  ${TS_FILES}
+    	SOURCE_TARGETS ${PROJECT_NAME}
+    	LUPDATE_TARGET update_translations
+        COMMENT "Updating .ts files from sources/ (lupdate) - developer target, run explicitly"
+    )
+else()
+    qt5_add_translation(QM_FILES ${TS_FILES})
+    set_source_files_properties(${TS_FILES} PROPERTIES OUTPUT_LOCATION "${QET_DIR}/lang")
+    add_custom_target(update_translations
+        COMMAND $<TARGET_FILE:Qt${QT_VERSION_MAJOR}::lupdate> ${CMAKE_SOURCE_DIR}/sources -ts ${TS_FILES}
+        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+        COMMENT "Updating .ts files from sources/ (lupdate) - developer target, run explicitly"
+        VERBATIM
+    )
+endif()
+
 # Optional precompiled headers -- see QET_ENABLE_PCH in
 # cmake/developer_options.cmake for what this trades away.
 #
@@ -180,7 +196,7 @@ target_link_libraries(
     pugixml::pugixml
     SingleApplication::SingleApplication
     SQLite3::SQLite3
-    ${KF5_PRIVATE_LIBRARIES}
+    ${KF_PRIVATE_LIBRARIES}
     ${QET_PRIVATE_LIBRARIES}
 )
 
@@ -221,7 +237,7 @@ target_include_directories(
     ${QET_DIR}/sources/svg
 )
 
-if(NOT BUILD_WITH_KF5)
+if(NOT BUILD_WITH_KF)
     target_include_directories(
         ${PROJECT_NAME}
         PRIVATE

build-aux/windows/nsis_base/files/README.md

@@ -40,8 +40,8 @@ git clone --recursive https://github.com/qelectrotech/qelectrotech-source-mirror
 Here are the technical choices made for the software development:
 
 *   Integrated development environment: [Qt Framework](https://www.qt.io/ide/)
-*   Libraries: Qt 5.x
-*   [KF5 Framework](https://github.com/KDE)  
+*   Libraries: Qt 5.x / Qt 6.x
+*   [KF5/6 Framework](https://github.com/KDE)  
     [Cmake](https://cmake.org/install/)   
     [kcoreaddons](https://github.com/KDE/kcoreaddons/tree/kf5)   
     [kwidgetsaddons](https://github.com/KDE/kwidgetsaddons/tree/kf5).  

cmake/define_definitions.cmake

@@ -62,10 +62,10 @@ message("PROJECT_SOURCE_DIR        :" ${PROJECT_SOURCE_DIR})
 message("QET_DIR                   :" ${QET_DIR})
 message("GIT_COMMIT_SHA            :" ${GIT_COMMIT_SHA})
 
-if(BUILD_WITH_KF5)
-  message("KF5_GIT_TAG               :" ${KF5_GIT_TAG})
+if(BUILD_WITH_KF)
+  message("KF_GIT_TAG               :" ${KF5_GIT_TAG})
 else()
-  add_definitions(-DBUILD_WITHOUT_KF5)
+  add_definitions(-DBUILD_WITHOUT_KF)
 endif()
 message("QET_COMPONENTS            :" ${QET_COMPONENTS})
 message("QT_VERSION_MAJOR          :" ${QT_VERSION_MAJOR})

cmake/developer_options.cmake

@@ -31,8 +31,11 @@ add_definitions(-DQT_MESSAGELOGCONTEXT)
 # In order to do so, uncomment the following line.
 #add_definitions(-DTODO_LIST)
 
-# Build with KF5
-option(BUILD_WITH_KF5 "Build with KF5" ON)
+# Build with KDE Frameworks. The major version (KF5/KF6) is derived
+# automatically from QT_VERSION_MAJOR -- KDE Frameworks deliberately
+# mirrors Qt's own major version numbering, so there is no independent
+# choice to make here. See cmake/fetch_kdeaddons.cmake.
+option(BUILD_WITH_KF "Build with KDE Frameworks" ON)
 
 # Precompiled headers for the Qt umbrella headers.
 #

cmake/fetch_kdeaddons.cmake

@@ -16,17 +16,24 @@
 
 message(" - fetch_kdeaddons")
 
-if(BUILD_WITH_KF5)
+# TODO remove path as soon as Qt5 gets retired
+if(BUILD_WITH_KF)
   Include(FetchContent)
 
-  option(BUILD_KF5 "Build KF5 libraries, use system ones otherwise" YES)
+  option(BUILD_KF "Build KF5 libraries, use system ones otherwise" YES)
 
-  if(BUILD_KF5)
+  if(BUILD_KF)
 
-    if(NOT DEFINED KF5_GIT_TAG)
+  if(KF_MAJOR_VERSION EQUAL 5)
+    if(NOT DEFINED KF_GIT_TAG)
       #https://qelectrotech.org/forum/viewtopic.php?pid=13924#p13924
-      set(KF5_GIT_TAG v5.77.0)
+      set(KF_GIT_TAG v5.77.0)
     endif()
+  else()
+    if(NOT DEFINED KF_GIT_TAG)
+      set(KF_GIT_TAG v6.10.0)
+    endif()
+  endif()
 
     # Fix stop the run autotests of kcoreaddons
     # see
@@ -38,30 +45,40 @@ if(BUILD_WITH_KF5)
     # https://qelectrotech.org/forum/viewtopic.php?pid=13929#p13929
     set(KDE_SKIP_TEST_SETTINGS "TRUE")
     set(BUILD_TESTING "0")
+    
+    # QElectroTech is a plain QtWidgets application with no QML anywhere in
+    # it; these disable optional features of the fetched KF modules that
+    # would otherwise pull in extra Qt6 components (e.g. Qt6Qml) we don't
+    # have and don't need.
+    set(BUILD_DESIGNERPLUGIN OFF)
+    set(KCOREADDONS_USE_QML OFF)
+    set(BUILD_QCH OFF)
+    set(BUILD_SHARED_LIBS OFF)
+
     FetchContent_Declare(
       ecm
       GIT_REPOSITORY https://invent.kde.org/frameworks/extra-cmake-modules.git
-      GIT_TAG        ${KF5_GIT_TAG})
+      GIT_TAG        ${KF_GIT_TAG})
     FetchContent_MakeAvailable(ecm)
 
     FetchContent_Declare(
       kcoreaddons
       GIT_REPOSITORY https://invent.kde.org/frameworks/kcoreaddons.git
-      GIT_TAG        ${KF5_GIT_TAG})
+      GIT_TAG        ${KF_GIT_TAG})
     FetchContent_MakeAvailable(kcoreaddons)
 
     FetchContent_Declare(
       kwidgetsaddons
       GIT_REPOSITORY https://invent.kde.org/frameworks/kwidgetsaddons.git
-      GIT_TAG        ${KF5_GIT_TAG})
+      GIT_TAG        ${KF_GIT_TAG})
     FetchContent_MakeAvailable(kwidgetsaddons)
   else()
-    find_package(KF5CoreAddons REQUIRED)
-    find_package(KF5WidgetsAddons REQUIRED)
+    find_package(KF${KF_MAJOR_VERSION}CoreAddons REQUIRED)
+    find_package(KF${KF_MAJOR_VERSION}WidgetsAddons REQUIRED)
   endif()
 
-  set(KF5_PRIVATE_LIBRARIES
-    KF5::WidgetsAddons
-    KF5::CoreAddons
+  set(KF_PRIVATE_LIBRARIES
+    KF${KF_MAJOR_VERSION}::WidgetsAddons
+    KF${KF_MAJOR_VERSION}::CoreAddons
     )
 endif()

cmake/qet_compilation_vars.cmake

@@ -801,7 +801,7 @@ set(QET_SRC_FILES
   ${QET_DIR}/sources/xml/terminalstriplayoutpatternxml.h
   )
 
-if(NOT BUILD_WITH_KF5)
+if(NOT BUILD_WITH_KF)
   list(APPEND QET_SRC_FILES
     ${QET_DIR}/sources/ui/nokde/kautosavefile.cpp
     ${QET_DIR}/sources/ui/nokde/kautosavefile.h

sources/editor/ui/dynamictextfieldeditor.cpp

@@ -141,7 +141,7 @@ void DynamicTextFieldEditor::updateForm()
 		ui -> m_size_sb -> setValue(m_text_field.data() -> font().pointSize());
 		ui->m_keep_visual_rotation_cb->setChecked(m_text_field.data()->keepVisualRotation());
 		ui->m_rotation_point_center_cb->setChecked(m_text_field.data()->rotationPointCenter());
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 #else
 		m_color_kpb -> setColor(m_text_field.data() -> color());
 #endif
@@ -170,7 +170,7 @@ void DynamicTextFieldEditor::updateForm()
 
 void DynamicTextFieldEditor::setupWidget()
 {
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 #else
 	m_color_kpb = new KColorButton(this);
 	m_color_kpb->setObjectName(QString::fromUtf8("m_color_kpb"));

sources/editor/ui/dynamictextfieldeditor.h

@@ -21,7 +21,7 @@
 #include "../elementitemeditor.h"
 #include "../graphicspart/partdynamictextfield.h"
 
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 #else
 #	include <KColorButton>
 #endif
@@ -79,7 +79,7 @@ class DynamicTextFieldEditor : public ElementItemEditor {
 		QList<PartDynamicTextField*> m_parts;
 		QList<QMetaObject::Connection> m_connection_list;
 
-	#ifdef BUILD_WITHOUT_KF5
+	#ifdef BUILD_WITHOUT_KF
 	#else
 		KColorButton* m_color_kpb = nullptr;
 	#endif

sources/editor/ui/terminaleditor.cpp

@@ -40,7 +40,7 @@ TerminalEditor::TerminalEditor(QETElementEditor *editor, QWidget *parent) :
 {
 	ui->setupUi(this);
 
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 	m_color_pb = new QPushButton(this);
 	m_color_pb->setMinimumSize(40, 24);
 	connect(m_color_pb, &QPushButton::clicked, this, &TerminalEditor::labelColorClicked);
@@ -93,7 +93,7 @@ void TerminalEditor::updateForm()
 	ui->m_label_rotation_sb->setValue(static_cast<int>(m_part->labelRotation()));
 	ui->m_label_frame_cb->setChecked(m_part->labelFrame());
 
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 	QPixmap px(16, 16);
 	px.fill(m_part->labelColor());
 	m_color_pb->setIcon(QIcon(px));
@@ -410,7 +410,7 @@ void TerminalEditor::labelColorClicked()
 	if (m_locked) return;
 	m_locked = true;
 
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 	QColor new_color = QColorDialog::getColor(m_part->labelColor(), this);
 	if (new_color.isValid() && m_part->labelColor() != new_color) {
 		auto undo = new QPropertyUndoCommand(m_part, "label_color", m_part->labelColor(), new_color);

sources/editor/ui/terminaleditor.h

@@ -21,7 +21,7 @@
 #include <QWidget>
 #include "../elementitemeditor.h"
 
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 #include <QPushButton>
 #else
 #include <KColorButton>
@@ -78,7 +78,7 @@ class TerminalEditor : public ElementItemEditor
 										 m_change_connections;
 		PartTerminal *m_part = nullptr;
 		bool m_locked = false;
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 		QPushButton *m_color_pb;
 #else
 		KColorButton *m_color_pb;

sources/editor/ui/texteditor.cpp

@@ -63,7 +63,7 @@ void TextEditor::updateForm()
 	m_rotation_sb -> setValue(m_text -> rotation());
 	m_size_sb -> setValue(m_text -> font().pointSize());
 	m_font_pb -> setText(m_text -> font().family());
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 #else
 	m_color_pb -> setColor(m_text -> defaultTextColor());
 #endif
@@ -346,7 +346,7 @@ void TextEditor::setUpWidget(QWidget *parent)
 	m_line_edit->setPlaceholderText(tr("Entrer votre texte ici"));
 
 	gridLayout->addWidget(m_line_edit, 0, 0, 1, 6);
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 #else
 	m_color_pb = new KColorButton(parent);
 	m_color_pb->setObjectName(QString::fromUtf8("m_color_pb"));

sources/editor/ui/texteditor.h

@@ -25,7 +25,7 @@
 #include <QSpinBox>
 #include <QLineEdit>
 #include <QPushButton>
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 #else
 #include <KColorButton>
 #endif
@@ -65,7 +65,7 @@ class TextEditor : public ElementItemEditor {
 		QSpinBox *m_size_sb;
 		QLineEdit *m_line_edit;
 		QPushButton *m_font_pb;
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 #else
 		KColorButton *m_color_pb;
 #endif

sources/qetapp.cpp

@@ -50,7 +50,7 @@
 #include <QFontDatabase>
 #include <QProcessEnvironment>
 #include <QRegularExpression>
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 #	include "ui/nokde/kautosavefile.h"
 #else
 #	include <KAutoSaveFile>

sources/qetdiagrameditor.cpp

@@ -57,7 +57,7 @@
 #include <QDateTime>
 #include <QDebug>
 #include <QDir>
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 #	include "ui/nokde/kautosavefile.h"
 #else
 #	include <KAutoSaveFile>

sources/qetproject.h

@@ -29,7 +29,7 @@
 #include "titleblock/templatescollection.h"
 #include "titleblockproperties.h"
 #include "diagram.h"
-#ifdef BUILD_WITHOUT_KF5
+#ifdef BUILD_WITHOUT_KF
 #	include "ui/nokde/kautosavefile.h"
 #else
 #	include <KAutoSaveFile>

tests/catch/CMakeLists.txt

@@ -90,7 +90,7 @@ add_executable(
     ${QET_DIR}/sources/borderproperties.h
     )
 
-if(NOT BUILD_WITH_KF5)
+if(NOT BUILD_WITH_KF)
     target_sources(
         ${PROJECT_NAME}
         PRIVATE
@@ -109,7 +109,7 @@ target_link_libraries(
     PUBLIC
     Catch2::Catch2
     PRIVATE
-    ${KF5_PRIVATE_LIBRARIES}
+    ${KF_PRIVATE_LIBRARIES}
     ${QET_PRIVATE_LIBRARIES})
 
 if (DEFINED ENV{CATCH_INCLUDE_DIR})

tests/googlemock/CMakeLists.txt

@@ -85,6 +85,6 @@ target_link_libraries(
     PUBLIC
     gmock gmock_main
     PRIVATE
-    ${KF5_PRIVATE_LIBRARIES}
+    ${KF_PRIVATE_LIBRARIES}
     ${QET_PRIVATE_LIBRARIES})
 

tests/googletest/CMakeLists.txt

@@ -84,6 +84,6 @@ target_link_libraries(
     PUBLIC
     gtest gtest_main
     PRIVATE
-    ${KF5_PRIVATE_LIBRARIES}
+    ${KF_PRIVATE_LIBRARIES}
     ${QET_PRIVATE_LIBRARIES})
 

tests/qttest/CMakeLists.txt

@@ -74,6 +74,6 @@ target_link_libraries(
   ${PROJECT_NAME}
   PRIVATE
   Qt::Test
-  ${KF5_PRIVATE_LIBRARIES}
+  ${KF_PRIVATE_LIBRARIES}
   ${QET_PRIVATE_LIBRARIES})