fix: The QtStartUpFunction function may be called repeatedly

Don't call pre routine function in qAddPreRoutine if
the qt_call_pre_routines is not called

Task-number: QTBUG-90341
Change-Id: I0ee70561dc57b857f8b3b1cf42c9dfe0cf45bd49
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
(cherry picked from commit 22e967c3049608f82abd32a0beb0b4b36ee134bf)

src/corelib/kernel/qcoreapplication.cpp

@@ -252,6 +252,7 @@ Q_GLOBAL_STATIC(QStartUpFuncList, preRList)
 typedef QList<QtCleanUpFunction> QVFuncList;
 Q_GLOBAL_STATIC(QVFuncList, postRList)
 static QBasicMutex globalRoutinesMutex;
+static bool preRoutinesCalled = false;
 
 /*!
     \internal
@@ -265,8 +266,10 @@ void qAddPreRoutine(QtStartUpFunction p)
     if (!list)
         return;
 
-    if (QCoreApplication::instance())
+    if (preRoutinesCalled) {
+        Q_ASSERT(QCoreApplication::instance());
         p();
+    }
 
     // Due to C++11 parallel dynamic initialization, this can be called
     // from multiple threads.
@@ -294,6 +297,9 @@ void qRemovePostRoutine(QtCleanUpFunction p)
 
 static void qt_call_pre_routines()
 {
+    // After will be allowed invoke QtStartUpFunction when calling qAddPreRoutine
+    preRoutinesCalled = true;
+
     if (!preRList.exists())
         return;
 
@@ -855,6 +861,8 @@ void QCoreApplicationPrivate::init()
 */
 QCoreApplication::~QCoreApplication()
 {
+    preRoutinesCalled = false;
+
     qt_call_post_routines();
 
     self = nullptr;

tests/auto/cmake/CMakeLists.txt

@@ -228,3 +228,6 @@ _qt_internal_test_expect_pass(test_add_resources_binary_generated
                               BINARY test_add_resources_binary_generated)
 
 include(test_plugin_shared_static_flavor.cmake)
+
+_qt_internal_test_expect_pass(tst_qaddpreroutine
+                              BINARY tst_qaddpreroutine)

tests/auto/cmake/tst_qaddpreroutine/CMakeLists.txt

@@ -0,0 +1,48 @@
+#####################################################################
+## tst_qaddpreroutine Test:
+#####################################################################
+cmake_minimum_required(VERSION 3.16)
+
+if(DEFINED CMAKE_Core_MODULE_MAJOR_VERSION)
+    set(project_version "${CMAKE_Core_MODULE_MAJOR_VERSION}.\
+${CMAKE_Core_MODULE_MINOR_VERSION}.${CMAKE_Core_MODULE_PATCH_VERSION}"
+    )
+else()
+    set(project_version "6.0.0")
+endif()
+
+project(tst_qaddpreroutine
+        LANGUAGES CXX
+        VERSION "${project_version}"
+)
+
+find_package(Qt6 COMPONENTS Core BuildInternals CONFIG REQUIRED)
+qt_prepare_standalone_project()
+
+find_package(Qt6 COMPONENTS Gui Test CONFIG REQUIRED)
+
+qt_internal_add_plugin(QTBUG_90341ThemePlugin
+    OUTPUT_NAME QTBUG_90341
+    OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}"
+    TYPE platformthemes
+    DEFAULT_IF FALSE
+    SOURCES
+        plugin.cpp
+    SKIP_INSTALL
+    PUBLIC_LIBRARIES
+        Qt::Core
+        Qt::Gui
+        Qt::GuiPrivate
+)
+
+qt_internal_add_test(tst_qaddpreroutine
+    SOURCES
+        tst_qaddpreroutine.cpp
+    PUBLIC_LIBRARIES
+        Qt::Gui
+)
+
+qt6_import_plugins(tst_qaddpreroutine INCLUDE QTBUG_90341)
+
+target_compile_definitions(tst_qaddpreroutine
+    PRIVATE QT_QPA_PLATFORM_PLUGIN_PATH=\"${CMAKE_BINARY_DIR}\")

tests/auto/cmake/tst_qaddpreroutine/plugin.cpp

@@ -0,0 +1,70 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 zccrs <zccrs@live.com>, JiDe Zhang <zhangjide@uniontech.com>.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <qpa/qplatformthemeplugin.h>
+#include <qpa/qplatformtheme.h>
+#include <QCoreApplication>
+
+QT_BEGIN_NAMESPACE
+
+// The "test_function_call_count" property will be used in the "tst_qaddpreroutine.cpp".
+// This plugin is part of the test case. It is used to call qAddPreRoutine through
+// Q_COREAPP_STARTUP_FUNCTION on the plugin loading. Please treat it as a whole
+// with "tst_qaddpreroutine.cpp".
+static void test()
+{
+    Q_ASSERT(qApp != nullptr);
+    int call_count = qApp->property("test_function_call_count").toInt();
+    // Record the number of times A is called, in this example, it should be called only once.
+    qApp->setProperty("test_function_call_count", call_count + 1);
+}
+Q_COREAPP_STARTUP_FUNCTION(test)
+
+class ThemePlugin : public QPlatformThemePlugin
+{
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID QPlatformThemeFactoryInterface_iid FILE "plugin.json")
+
+public:
+    QPlatformTheme *create(const QString &key, const QStringList &params) override;
+};
+
+QPlatformTheme *ThemePlugin::create(const QString &key, const QStringList &params)
+{
+    Q_UNUSED(key)
+    Q_UNUSED(params);
+
+    // Used to verify whether this plugin was successfully loaded.
+    qputenv("QTBUG_90341_ThemePlugin", "1");
+
+    return new QPlatformTheme();
+}
+
+QT_END_NAMESPACE
+
+#include "plugin.moc"

tests/auto/cmake/tst_qaddpreroutine/plugin.json

@@ -0,0 +1,3 @@
+{
+    "Keys": ["QTBUG_90341"]
+}

tests/auto/cmake/tst_qaddpreroutine/tst_qaddpreroutine.cpp

@@ -0,0 +1,69 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 zccrs <zccrs@live.com>, JiDe Zhang <zhangjide@uniontech.com>.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QTest>
+#include <QGuiApplication>
+
+class tst_qAddPreRoutine : public QObject
+{
+    Q_OBJECT
+
+public:
+    static void initMain()
+    {
+        // The purpose of this use case is indeed to test "qAddPreRoutine", but
+        // as you can see, there is nowhere to call "qAddPreRoutine". Please see
+        // the following two lines of code, which set the "QT_QPA_PLATFORM_PLUGIN_PATH"
+        // and "QT_QPA_PLATFORMTHEME" environment variables that a new platform
+        // theme plugin will be loaded, and the Q_COREAPP_STARTUP_FUNCTION macro
+        // is used in this plugin, which will cause "qAddPreRoutine" to be called
+        // indirectly in the Q*Application class when load the platform theme plugin.
+        // See the "plugin.cpp" file.
+#ifndef Q_OS_ANDROID // The plug-in is in the apk package, no need to specify its directory
+        qputenv("QT_QPA_PLATFORM_PLUGIN_PATH", QT_QPA_PLATFORM_PLUGIN_PATH);
+#endif
+        qputenv("QT_QPA_PLATFORMTHEME", "QTBUG_90341");
+    }
+
+private slots:
+    void tst_QTBUG_90341()
+    {
+#ifdef Q_OS_ANDROID
+        QSKIP("Android can't load the platform theme plugin this test needs, see QTBUG-92893");
+#endif
+        QVERIFY2(qEnvironmentVariableIsSet("QTBUG_90341_ThemePlugin"),
+                 "The \"QTBUG_90341\" theme plugin not loaded.");
+        // This "test_function_call_count" property is assigned in the "QTBUG_90341" plugin.
+        // See the "plugin.cpp" file.
+        QCOMPARE(qApp->property("test_function_call_count").toInt(), 1);
+    }
+};
+
+QTEST_MAIN(tst_qAddPreRoutine)
+
+#include "tst_qaddpreroutine.moc"