Add plugins of imported QtModules to the _qt_plugins property

This covers the following use case:
QtModuleX is pre-built and installed, it's imported. The plugin has
a PLUGIN_TYPE that is associated with QtModuleX and is built with
application that links QtModuleX. When deploying the application
it's expected that the plugin is deployed, as the one that belongs
to the linked QtModuleX.

This ensures that we udpate the internal _qt_plugins property that
is used in the __qt_internal_collect_plugin_targets_from_dependencies
function.

Pick-to: 6.5 6.6 6.7
Change-Id: I9824351ebab5a24509800da4db69f1e282a35884
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

4 files changed, 59 insertions, 0 deletions

diff --git a/tests/auto/cmake/CMakeLists.txt b/tests/auto/cmake/CMakeLists.txt
index f71468cee8..7152f820f5 100644
--- a/tests/auto/cmake/CMakeLists.txt
+++ b/tests/auto/cmake/CMakeLists.txt
@@ -393,3 +393,6 @@ endif()
 
 _qt_internal_test_expect_pass(test_config_expressions)
 _qt_internal_test_expect_pass(test_QTP0003)
+if(NOT NO_GUI)
+    _qt_internal_test_expect_pass(test_collecting_plugins)
+endif()
diff --git a/tests/auto/cmake/test_collecting_plugins/CMakeLists.txt b/tests/auto/cmake/test_collecting_plugins/CMakeLists.txt
new file mode 100644
index 0000000000..246acd4c71
--- /dev/null
+++ b/tests/auto/cmake/test_collecting_plugins/CMakeLists.txt
@@ -0,0 +1,31 @@
+# Copyright (C) 2024 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+cmake_minimum_required(VERSION 3.16)
+
+project(test_collecting_plugins
+    VERSION
+        "${CMAKE_Core_MODULE_MAJOR_VERSION}.${CMAKE_Core_MODULE_MINOR_VERSION}.${CMAKE_Core_MODULE_PATCH_VERSION}")
+
+find_package(Qt6 COMPONENTS Core Gui BuildInternals REQUIRED)
+
+qt_prepare_standalone_project()
+
+qt_internal_add_plugin(QTestImagePlugin
+    SHARED
+    PLUGIN_TYPE imageformats
+    SOURCES
+        plugin.cpp
+    LIBRARIES
+        Qt6::Gui
+    SKIP_INSTALL # Make sure that we do not package this plugin
+)
+
+qt_add_executable(TestExecutable main.cpp)
+target_link_libraries(TestExecutable PRIVATE Qt6::Gui)
+
+__qt_internal_collect_plugin_targets_from_dependencies(TestExecutable plugin_targets)
+
+if(NOT "QTestImagePlugin" IN_LIST plugin_targets)
+    message(FATAL_ERROR "QTestImagePlugin plugin is missing")
+endif()
diff --git a/tests/auto/cmake/test_collecting_plugins/main.cpp b/tests/auto/cmake/test_collecting_plugins/main.cpp
new file mode 100644
index 0000000000..09225de205
--- /dev/null
+++ b/tests/auto/cmake/test_collecting_plugins/main.cpp
@@ -0,0 +1,7 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
+
+int main(int, char *[])
+{
+    return 0;
+}
diff --git a/tests/auto/cmake/test_collecting_plugins/plugin.cpp b/tests/auto/cmake/test_collecting_plugins/plugin.cpp
new file mode 100644
index 0000000000..f844d86c4e
--- /dev/null
+++ b/tests/auto/cmake/test_collecting_plugins/plugin.cpp
@@ -0,0 +1,18 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
+
+#include <qimageiohandler.h>
+
+class TestImagePlugin : public QImageIOPlugin
+{
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QImageIOHandlerFactoryInterface")
+public:
+    Capabilities capabilities(QIODevice *, const QByteArray &) const override { return {}; }
+    QImageIOHandler *create(QIODevice *, const QByteArray & = QByteArray()) const override
+    {
+        return nullptr;
+    }
+};
+
+#include "plugin.moc"