CMake: Walk plugin private deps for computed static qml plugin deps

When setting up extra dependencies for a qml static plugin we only
walked private dependencies of the backing library, but the plugin
itself might have extra dependencies on it which are not on the
backing library.

An example of this is the qtquickcontrols2plugin which links
against QuickControls2ImplPrivate.

This means the qtquickcontrols2impl plugin should be a dependency of
the qtquickcontrols2plugin.

Make sure to walk the plugin's private dependencies in addition to the
backing lib private dependencies. Also make sure not to accidentally
create a linking cycle by filtering out the current plugin from being
added to itself as a result of the walk.

Amends 6fd1216801f078f65be2cbc748cc459cb6912a4f

Fixes: QTBUG-97099
Change-Id: I61981826283944b160888dd64f3a6afd23495d79
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
(cherry picked from commit 9fc302e6d146878103b3d105dce49c7695fcf93a)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 29 insertions, 12 deletions

diff --git a/src/qml/Qt6QmlMacros.cmake b/src/qml/Qt6QmlMacros.cmake
index 02622c63b5..45dffde6ca 100644
--- a/src/qml/Qt6QmlMacros.cmake
+++ b/src/qml/Qt6QmlMacros.cmake
@@ -2154,24 +2154,22 @@ function(_qt_internal_add_static_qml_plugin_dependencies plugin_target backing_t
     endif()
     set_target_properties("${plugin_target}" PROPERTIES _qt_extra_static_qml_plugin_deps_added TRUE)
 
+    # Get the install plugin target name, which we will need for filtering later on.
+    if(TARGET "${backing_target}")
+        get_target_property(installed_plugin_target
+                            "${backing_target}" _qt_qml_module_installed_plugin_target)
+    endif()
+
     if(NOT backing_target STREQUAL plugin_target AND TARGET "${backing_target}")
         set(has_backing_lib TRUE)
     else()
         set(has_backing_lib FALSE)
     endif()
 
-    # Target who's direct dependencies will be walked to set up additional dependencies for
-    # a static qml plugin.
-    if(has_backing_lib)
-        set(target_with_candidate_qml_module_deps "${backing_target}")
-    else()
-        set(target_with_candidate_qml_module_deps "${plugin_target}")
-    endif()
-
     get_target_property(plugin_type ${plugin_target} TYPE)
     set(skip_prl_marker "$<BOOL:QT_IS_PLUGIN_GENEX>")
 
-    # If ${plugin_target} is a static qml plugin, recursively get its private dependencies (or its
+    # If ${plugin_target} is a static qml plugin, recursively get its private dependencies (and its
     # backing lib private deps), identify which of those are qml modules, extract any associated qml
     # plugin target from those qml modules and make them dependencies of ${plugin_target}.
     #
@@ -2187,10 +2185,25 @@ function(_qt_internal_add_static_qml_plugin_dependencies plugin_target backing_t
     set(additional_plugin_deps "")
 
     if(plugin_type STREQUAL "STATIC_LIBRARY")
+        set(all_private_deps "")
+
+        # We walk both plugin_target and backing_lib private deps because they can have differing
+        # dependencies and we want to consider all of them.
         __qt_internal_collect_all_target_dependencies(
-            "${target_with_candidate_qml_module_deps}" plugin_private_deps)
+            "${plugin_target}" plugin_private_deps)
+        if(plugin_private_deps)
+            list(APPEND all_private_deps ${plugin_private_deps})
+        endif()
+
+        if(has_backing_lib)
+            __qt_internal_collect_all_target_dependencies(
+                "${backing_target}" backing_lib_private_deps)
+            if(backing_lib_private_deps)
+                list(APPEND all_private_deps ${backing_lib_private_deps})
+            endif()
+        endif()
 
-        foreach(dep IN LISTS plugin_private_deps)
+        foreach(dep IN LISTS all_private_deps)
             if(NOT TARGET "${dep}")
                 continue()
             endif()
@@ -2218,7 +2231,11 @@ function(_qt_internal_add_static_qml_plugin_dependencies plugin_target backing_t
                     set(associated_qml_plugin "${associated_qml_plugin_candidate}")
                 endif()
 
-                if(associated_qml_plugin)
+                # We need to filter out adding the plugin_target as a dependency to itself,
+                # when walking the backing lib of the plugin_target.
+                if(associated_qml_plugin
+                        AND NOT associated_qml_plugin STREQUAL plugin_target
+                        AND NOT associated_qml_plugin STREQUAL installed_plugin_target)
                     # Abuse a genex marker, to skip the dependency to be added into prl files.
                     # TODO: Introduce a more generic marker name in qtbase specifically
                     # for skipping deps in prl file deps generation.