Provide a way to specify extra tool package dependencies

In the qtwayland repo, both WaylandClient and WaylandCompositor
packages need access to the qtwaylandscanner tool. That means
that the add_qt_tool(qtwaylandscanner) can't use the TOOLS_TARGET
argument to associate a dependency with only one of the above
modules.

Instead add_qt_tool now allows specifying a non-existent module
name for the TOOLS_TARGET argument, which can be manually
depended on by other packages.
Actually, you could specify the non-existent module before as
well, but that didn't do everything that had to be done.

This required a bit of refactoring in how the Dependencies file
for Tools packages is created. Now the file is created in
qt_export_tools.

Two new functions were also added to allow recording additional
dependencies between packages.

Also some bug fixes were done to make it all work. Specifically
the _FOUND variable generated in the Dependencies file was incorrect.
Also there are some quotes missing when appending extra package
dependencies via the QT_EXTRA_PACKAGE_DEPENDENCIES property.

Change-Id: I167efec16dff8d036e191df3572ea72764e22bc5
Reviewed-by: Leander Beernaert <leander.beernaert@qt.io>
Reviewed-by: Qt CMake Build Bot
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

cmake/QtBuild.cmake

@@ -1715,7 +1715,18 @@ function(qt_export_tools module_name)
     # Also assemble a list of tool targets to expose in the config file for informational purposes.
     set(extra_cmake_statements "")
     set(tool_targets "")
+
+    # List of package dependencies that need be find_package'd when using the Tools package.
+    set(package_deps "")
+
     foreach(tool_name ${QT_KNOWN_MODULE_${module_name}_TOOLS})
+        # Specific tools can have package dependencies.
+        # e.g. qtwaylandscanner depends on WaylandScanner (non-qt package).
+        get_target_property(extra_packages "${tool_name}" QT_EXTRA_PACKAGE_DEPENDENCIES)
+        if(extra_packages)
+            list(APPEND package_deps "${extra_packages}")
+        endif()
+
         set(extra_cmake_statements "${extra_cmake_statements}
 if (NOT QT_NO_CREATE_TARGETS)
     get_property(is_global TARGET ${INSTALL_CMAKE_NAMESPACE}::${tool_name} PROPERTY IMPORTED_GLOBAL)
@@ -1730,6 +1741,31 @@ endif()
     string(APPEND extra_cmake_statements
 "set(${QT_CMAKE_EXPORT_NAMESPACE}${module_name}Tools_TARGETS \"${tool_targets}\")")
 
+    # Extract package dependencies that were determined in QtPostProcess, but only if ${module_name}
+    # is an actual target.
+    # module_name can be a non-existent target, if the tool doesn't have an existing associated
+    # module, e.g. qtwaylandscanner.
+    if(TARGET "${module_name}")
+        get_target_property(module_package_deps "${module_name}" _qt_tools_package_deps)
+        if(module_package_deps)
+            list(APPEND package_deps "${module_package_deps}")
+        endif()
+    endif()
+
+    # Configure and install dependencies file for the ${module_name}Tools package.
+    configure_file(
+        "${QT_CMAKE_DIR}/QtModuleToolsDependencies.cmake.in"
+        "${config_build_dir}/${INSTALL_CMAKE_NAMESPACE}${target}Dependencies.cmake"
+        @ONLY
+    )
+
+    qt_install(FILES
+        "${config_build_dir}/${INSTALL_CMAKE_NAMESPACE}${target}Dependencies.cmake"
+        DESTINATION "${config_install_dir}"
+        COMPONENT Devel
+    )
+
+    # Configure and install the ${module_name}Tools package Config file.
     configure_package_config_file(
         "${QT_CMAKE_DIR}/QtModuleToolsConfig.cmake.in"
         "${config_build_dir}/${INSTALL_CMAKE_NAMESPACE}${target}Config.cmake"
@@ -1760,6 +1796,38 @@ endif()
     #                                                    CONFIG_INSTALL_DIR ${config_install_dir})
 endfunction()
 
+# This function records a dependency between ${target_name} and ${dep_package_name}.
+# at the CMake package level.
+# E.g. The Tools package that provides the qtwaylandscanner target
+# needs to call find_package(WaylandScanner) (non-qt-package).
+# main_target_name = qtwaylandscanner
+# dep_package_name = WaylandScanner
+function(qt_record_extra_package_dependency main_target_name dep_package_name dep_package_version)
+    get_target_property(extra_packages "${main_target_name}" QT_EXTRA_PACKAGE_DEPENDENCIES)
+    if(NOT extra_packages)
+        set(extra_packages "")
+    endif()
+
+    list(APPEND extra_packages "${dep_package_name}\;${dep_package_version}")
+    set_target_properties("${main_target_name}" PROPERTIES QT_EXTRA_PACKAGE_DEPENDENCIES
+                                                           "${extra_packages}")
+endfunction()
+
+# This function records a dependency between ${main_target_name} and ${dep_target_name}
+# at the CMake package level.
+# E.g. Qt6CoreConfig.cmake needs to find_package(Qt6WinMain).
+# main_target_name = Core
+# dep_target_name = WinMain
+# This is just a convenience function that deals with Qt targets and their associated packages
+# instead of raw package names.
+function(qt_record_extra_qt_package_dependency main_target_name dep_target_name
+                                                                dep_package_version)
+    # WinMain -> Qt6WinMain.
+    qt_internal_module_info(qtfied_target_name "${dep_target_name}")
+    qt_record_extra_package_dependency("${main_target_name}" "${qtfied_target_name_versioned}"
+                                                             "${dep_package_version}")
+endfunction()
+
 function(qt_internal_check_directory_or_type name dir type default result_var)
     if ("x${dir}" STREQUAL x)
         if("x${type}" STREQUAL x)

cmake/QtModuleToolsDependencies.cmake.in

@@ -1,5 +1,5 @@
 # Find "ModuleTools" dependencies, which are other ModuleTools packages.
-set(_tool_deps "@tool_deps@")
+set(_tool_deps "@package_deps@")
 foreach(_target_dep ${_tool_deps})
     list(GET _target_dep 0 pkg)
     list(GET _target_dep 1 version)
@@ -9,7 +9,7 @@ foreach(_target_dep ${_tool_deps})
     endif()
 
     if (NOT ${pkg}_FOUND)
-        set(@INSTALL_CMAKE_NAMESPACE@@target@Tools_FOUND FALSE)
+        set(@INSTALL_CMAKE_NAMESPACE@@target@_FOUND FALSE)
         return()
     endif()
 endforeach()

cmake/QtPostProcess.cmake

@@ -82,7 +82,7 @@ function(qt_internal_create_module_depends_file target)
         get_target_property(extra_depends "${target}" QT_EXTRA_PACKAGE_DEPENDENCIES)
     endif()
     if(NOT extra_depends STREQUAL "${extra_depends}-NOTFOUND")
-        list(APPEND target_deps ${extra_depends})
+        list(APPEND target_deps "${extra_depends}")
     endif()
 
     # Used for assembling the content of an include/Module/ModuleDepends.h header.
@@ -183,23 +183,8 @@ function(qt_internal_create_module_depends_file target)
 
     endif()
     if(tool_deps)
-        set(path_suffix "${INSTALL_CMAKE_NAMESPACE}${target}Tools")
+        # The value of the property will be used by qt_export_tools.
-        qt_path_join(config_build_dir ${QT_CONFIG_BUILD_DIR} ${path_suffix})
+        set_property(TARGET "${target}" PROPERTY _qt_tools_package_deps "${tool_deps}")
-        qt_path_join(config_install_dir ${QT_CONFIG_INSTALL_DIR} ${path_suffix})
-
-        # Configure and install ModuleToolDependencies file.
-        configure_file(
-            "${QT_CMAKE_DIR}/QtModuleToolsDependencies.cmake.in"
-            "${config_build_dir}/${INSTALL_CMAKE_NAMESPACE}${target}ToolsDependencies.cmake"
-            @ONLY
-        )
-
-        qt_install(FILES
-            "${config_build_dir}/${INSTALL_CMAKE_NAMESPACE}${target}ToolsDependencies.cmake"
-            DESTINATION "${config_install_dir}"
-            COMPONENT Devel
-        )
-
     endif()
 endfunction()
 
@@ -378,12 +363,14 @@ function(qt_internal_create_config_file_for_standalone_tests)
     )
 endfunction()
 
-qt_create_tools_config_files()
 qt_internal_create_depends_files()
 qt_generate_build_internals_extra_cmake_code()
 qt_internal_create_plugins_files()
 qt_internal_create_config_file_for_standalone_tests()
 
+# Needs to run after qt_internal_create_depends_files.
+qt_create_tools_config_files()
+
 if (ANDROID)
     qt_modules_process_android_dependencies()
 endif()

src/corelib/CMakeLists.txt

@@ -1154,8 +1154,7 @@ if(WIN32)
     set(isPolicyNEW $<TARGET_POLICY:CMP0020>)
 
     target_link_libraries(Core INTERFACE $<$<AND:${isExe},${isWin32},${isNotExcluded},${isPolicyNEW}>:Qt::WinMain>)
-    qt_internal_module_info(win_main_module WinMain)
+    qt_record_extra_qt_package_dependency(Core WinMain "${PROJECT_VERSION}")
-    set_property(TARGET Core APPEND PROPERTY QT_EXTRA_PACKAGE_DEPENDENCIES "${win_main_module_versioned}\\\;${PROJECT_VERSION}")
 endif()
 # special case end