CMake: Remove custom Qt6 3rd party dependency implementation

Use _qt_internal_find_third_party_dependencies instead.
We rely on the inner find_dependency call to set the
Qt6_NOT_FOUND_MESSAGE message when a dependency is not found.
This implies removing the custom FATAL_ERROR handling
and relying on the parent find_package to display the
Qt6_NOT_FOUND_MESSAGE message.

We also clear Qt6_FIND_COMPONENTS if a dependency is not found.
No need to look for Qt packages if the Qt6 dependency was not met.
This reduces the amount of recursive error messages.

Task-number: QTBUG-104998
Change-Id: I5c611aaededfa63eb507ec5385b37a2fb6fcc698
Reviewed-by: Jörg Bornemann <joerg.bornemann@qt.io>
(cherry picked from commit 6a2358e20f03a89ce08724355b2f4863155272f9)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

2 files changed, 7 insertions, 48 deletions

diff --git a/cmake/QtConfig.cmake.in b/cmake/QtConfig.cmake.in
index 8ad4e45822..9f8c80a2e5 100644
--- a/cmake/QtConfig.cmake.in
+++ b/cmake/QtConfig.cmake.in
@@ -150,10 +150,10 @@ set(__qt_sanitizer_options_set TRUE)
 include(CMakeFindDependencyMacro)
 if(EXISTS "${CMAKE_CURRENT_LIST_DIR}/@INSTALL_CMAKE_NAMESPACE@Dependencies.cmake")
     include("${CMAKE_CURRENT_LIST_DIR}/@INSTALL_CMAKE_NAMESPACE@Dependencies.cmake")
-    if(NOT @INSTALL_CMAKE_NAMESPACE@_DEPENDENCIES_FOUND)
-        set(@INSTALL_CMAKE_NAMESPACE@_FOUND FALSE)
-        message(FATAL_ERROR "Failed to find Qt Platform dependency: "
-            "${@INSTALL_CMAKE_NAMESPACE@_DEPENDENCY_NOT_FOUND_MESSAGE}")
+    if(NOT @INSTALL_CMAKE_NAMESPACE@_FOUND)
+        # Clear the components, no need to look for them if dependencies were not found, otherwise
+        # you get a wall of recursive error messages.
+        set(@INSTALL_CMAKE_NAMESPACE@_FIND_COMPONENTS "")
     endif()
 endif()
 
diff --git a/cmake/QtConfigDependencies.cmake.in b/cmake/QtConfigDependencies.cmake.in
index b23b6681eb..52a0e1d224 100644
--- a/cmake/QtConfigDependencies.cmake.in
+++ b/cmake/QtConfigDependencies.cmake.in
@@ -1,51 +1,10 @@
-set(@INSTALL_CMAKE_NAMESPACE@_DEPENDENCIES_FOUND FALSE)
+set(@INSTALL_CMAKE_NAMESPACE@_FOUND FALSE)
 
 # note: _third_party_deps example: "ICU\\;FALSE\\;1.0\\;i18n uc data;ZLIB\\;FALSE\\;\\;"
 set(__qt_third_party_deps "@third_party_deps@")
 
 @third_party_extra@
 
-foreach(__qt_target_dep ${__qt_third_party_deps})
-    list(GET __qt_target_dep 0 __qt_pkg)
-    list(GET __qt_target_dep 1 __qt_is_optional)
-    list(GET __qt_target_dep 2 __qt_version)
-    list(GET __qt_target_dep 3 __qt_components)
-    list(GET __qt_target_dep 4 __qt_optional_components)
-    set(__qt_find_package_args "${__qt_pkg}")
-    if(__qt_version)
-        list(APPEND __qt_find_package_args "${__qt_version}")
-    endif()
-    if(__qt_components)
-        string(REPLACE " " ";" __qt_components "${__qt_components}")
-        list(APPEND __qt_find_package_args COMPONENTS ${__qt_components})
-    endif()
-    if(__qt_optional_components)
-        string(REPLACE " " ";" __qt_optional_components "${__qt_optional_components}")
-        list(APPEND __qt_find_package_args OPTIONAL_COMPONENTS ${__qt_optional_components})
-    endif()
+_qt_internal_find_third_party_dependencies(Platform __qt_third_party_deps)
 
-    # Already build an error message, because find_dependency calls return() on failure.
-    set(__qt_message "\nPackage: ${__qt_pkg}")
-    if(__qt_version)
-        string(APPEND __qt_message "\nVersion: ${__qt_version}")
-    endif()
-    if(__qt_components)
-        string(APPEND __qt_message "\nComponents: ${__qt_components}")
-    endif()
-    if(__qt_optional_components)
-        string(APPEND __qt_message "\nComponents: ${__qt_optional_components}")
-    endif()
-    set(@INSTALL_CMAKE_NAMESPACE@_DEPENDENCY_NOT_FOUND_MESSAGE "${__qt_message}")
-
-    if(__qt_is_optional)
-        if(${CMAKE_FIND_PACKAGE_NAME}_FIND_QUIETLY)
-            list(APPEND __qt_find_package_args QUIET)
-        endif()
-        find_package(${__qt_find_package_args})
-    else()
-        find_dependency(${__qt_find_package_args})
-    endif()
-endforeach()
-
-set(@INSTALL_CMAKE_NAMESPACE@_DEPENDENCIES_FOUND TRUE)
-unset(@INSTALL_CMAKE_NAMESPACE@_DEPENDENCY_NOT_FOUND_MESSAGE)
+set(@INSTALL_CMAKE_NAMESPACE@_FOUND TRUE)