shiboken: Introduce a function to get the type name of a polymorphic class

Helps for hierarchies that do not have virtual destructors where the
default typeid(t).name() does not work (QStyleOption).

Pick-to: 6.3
Fixes: PYSIDE-1909
Change-Id: I9ce3769a8c3550d011023597eede0ae6f8c9ad68
Reviewed-by: Christian Tismer <tismer@stackless.com>

9 files changed, 171 insertions, 3 deletions

diff --git a/sources/pyside6/PySide6/QtWidgets/typesystem_widgets_common.xml b/sources/pyside6/PySide6/QtWidgets/typesystem_widgets_common.xml
index fa973e52d..7a74d1820 100644
--- a/sources/pyside6/PySide6/QtWidgets/typesystem_widgets_common.xml
+++ b/sources/pyside6/PySide6/QtWidgets/typesystem_widgets_common.xml
@@ -88,7 +88,10 @@
   <function signature="qDrawPlainRect(QPainter*,int,int,int,int,const QColor&amp;,int,const QBrush*)"/>
   <function signature="qDrawPlainRect(QPainter*,const QRect&amp;,const QColor&amp;,int,const QBrush*)"/>
 
-  <object-type name="QStyleOption" polymorphic-id-expression="%1-&gt;type == QStyleOption::SO_Default">
+  <object-type name="QStyleOption" polymorphic-id-expression="%1-&gt;type == QStyleOption::SO_Default"
+               polymorphic-name-function="styleOptionType">
+    <inject-code class="native" position="beginning" file="../glue/qtwidgets.cpp"
+                 snippet="qstyleoption-typename"/>
     <enum-type name="OptionType"/>
     <enum-type name="StyleOptionType"/>
     <enum-type name="StyleOptionVersion"/>
diff --git a/sources/pyside6/PySide6/glue/qtwidgets.cpp b/sources/pyside6/PySide6/glue/qtwidgets.cpp
index 7511e89cc..b355f41cb 100644
--- a/sources/pyside6/PySide6/glue/qtwidgets.cpp
+++ b/sources/pyside6/PySide6/glue/qtwidgets.cpp
@@ -719,6 +719,63 @@ QAction *cppResult = %CPPSELF.exec(%1, %2, %3, %4);
 %PYARG_0 = %CONVERTTOPYTHON[QAction*](cppResult);
 // @snippet qmenu-exec-3
 
+// @snippet qstyleoption-typename
+const char *styleOptionType(const QStyleOption *o)
+{
+    switch (o->type) {
+    case QStyleOption::SO_Default:
+        break;
+    case QStyleOption::SO_FocusRect:
+        return "StyleOptionFocusRect";
+    case QStyleOption::SO_Button:
+        return "StyleOptionButton";
+    case QStyleOption::SO_Tab:
+        return "StyleOptionTab";
+    case QStyleOption::SO_MenuItem:
+        return "StyleOptionMenuItem";
+    case QStyleOption::SO_Frame:
+        return "StyleOptionFrame";
+    case QStyleOption::SO_ProgressBar:
+        return "StyleOptionProgressBar";
+    case QStyleOption::SO_ToolBox:
+        return "StyleOptionToolBox";
+    case QStyleOption::SO_Header:
+        return "StyleOptionHeader";
+    case QStyleOption::SO_DockWidget:
+        return "StyleOptionDockWidget";
+    case QStyleOption::SO_ViewItem:
+        return "StyleOptionViewItem";
+    case QStyleOption::SO_TabWidgetFrame:
+        return "StyleOptionTabWidgetFrame";
+    case QStyleOption::SO_TabBarBase:
+        return "StyleOptionTabBarBase";
+    case QStyleOption::SO_RubberBand:
+        return "StyleOptionRubberBand";
+    case QStyleOption::SO_ToolBar:
+        return "StyleOptionToolBar";
+    case QStyleOption::SO_GraphicsItem:
+        return "StyleOptionGraphicsItem";
+    case QStyleOption::SO_Slider:
+        return "StyleOptionSlider";
+    case QStyleOption::SO_SpinBox:
+        return "StyleOptionSpinBox";
+    case QStyleOption::SO_ToolButton:
+        return "StyleOptionToolButton";
+    case QStyleOption::SO_ComboBox:
+        return "StyleOptionComboBox";
+    case QStyleOption::SO_TitleBar:
+        return "StyleOptionTitleBar";
+    case QStyleOption::SO_GroupBox:
+        return "StyleOptionGroupBox";
+    case QStyleOption::SO_SizeGrip:
+        return "StyleOptionSizeGrip";
+    default:
+        break;
+    }
+    return "QStyleOption";
+}
+// @snippet qstyleoption-typename
+
 /*********************************************************************
  * CONVERSIONS
  ********************************************************************/
diff --git a/sources/pyside6/tests/QtWidgets/CMakeLists.txt b/sources/pyside6/tests/QtWidgets/CMakeLists.txt
index 8978df9a4..5989c0625 100644
--- a/sources/pyside6/tests/QtWidgets/CMakeLists.txt
+++ b/sources/pyside6/tests/QtWidgets/CMakeLists.txt
@@ -106,6 +106,7 @@ PYSIDE_TEST(qpicture_test.py)
 PYSIDE_TEST(qpushbutton_test.py)
 PYSIDE_TEST(qsplitter_test.py)
 PYSIDE_TEST(qstyle_test.py)
+PYSIDE_TEST(qstyleoption_test.py)
 PYSIDE_TEST(qtableview_test.py)
 PYSIDE_TEST(qtabwidget_test.py)
 PYSIDE_TEST(qtabwidgetclear_test.py)
diff --git a/sources/pyside6/tests/QtWidgets/qstyleoption_test.py b/sources/pyside6/tests/QtWidgets/qstyleoption_test.py
new file mode 100644
index 000000000..2cbdfcfbd
--- /dev/null
+++ b/sources/pyside6/tests/QtWidgets/qstyleoption_test.py
@@ -0,0 +1,68 @@
+#############################################################################
+##
+## Copyright (C) 2022 The Qt Company Ltd.
+## Contact: https://www.qt.io/licensing/
+##
+## This file is part of the test suite of Qt for Python.
+##
+## $QT_BEGIN_LICENSE:GPL-EXCEPT$
+## 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.
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+import sys
+import os
+import unittest
+
+from pathlib import Path
+sys.path.append(os.fspath(Path(__file__).resolve().parents[1]))
+from init_paths import init_test_paths
+init_test_paths(False)
+
+from helper.usesqapplication import UsesQApplication
+
+from PySide6.QtWidgets import (QApplication, QCommonStyle, QPushButton)
+
+
+text = ''
+
+
+class Style(QCommonStyle):
+
+    def drawControl(self, element, option, painter, widget=None):
+        # This should be a QStyleOptionButton with a "text" field
+        global text
+        text = option.text
+
+
+class StyleOptionTest(UsesQApplication):
+    '''PYSIDE-1909: Test cast to derived style option classes.'''
+
+    def testStyle(self):
+        global text
+        button = QPushButton("Hello World")
+        button.setStyle(Style())
+        button.show()
+        while not text:
+            QApplication.processEvents()
+        self.assertEqual(text, button.text())
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/sources/shiboken6/ApiExtractor/typesystem.cpp b/sources/shiboken6/ApiExtractor/typesystem.cpp
index ca9bcc67d..101be0c79 100644
--- a/sources/shiboken6/ApiExtractor/typesystem.cpp
+++ b/sources/shiboken6/ApiExtractor/typesystem.cpp
@@ -1242,6 +1242,7 @@ public:
     uint m_deleteInMainThread : 1;
 
     QString m_polymorphicIdValue;
+    QString m_polymorphicNameFunction;
     QString m_targetType;
     ComplexTypeEntry::TypeFlags m_typeFlags;
     ComplexTypeEntry::CopyableFlag m_copyableFlag = ComplexTypeEntry::Unknown;
@@ -1421,6 +1422,18 @@ QString ComplexTypeEntry::polymorphicIdValue() const
     return d->m_polymorphicIdValue;
 }
 
+QString ComplexTypeEntry::polymorphicNameFunction() const
+{
+    S_D(const ComplexTypeEntry);
+    return d->m_polymorphicNameFunction;
+}
+
+void ComplexTypeEntry::setPolymorphicNameFunction(const QString &n)
+{
+    S_D(ComplexTypeEntry);
+    d->m_polymorphicNameFunction = n;
+}
+
 QString ComplexTypeEntry::targetType() const
 {
     S_D(const ComplexTypeEntry);
diff --git a/sources/shiboken6/ApiExtractor/typesystem.h b/sources/shiboken6/ApiExtractor/typesystem.h
index 5c4689839..dd8b1524a 100644
--- a/sources/shiboken6/ApiExtractor/typesystem.h
+++ b/sources/shiboken6/ApiExtractor/typesystem.h
@@ -597,6 +597,9 @@ public:
     void setPolymorphicIdValue(const QString &value);
     QString polymorphicIdValue() const;
 
+    QString polymorphicNameFunction() const;
+    void setPolymorphicNameFunction(const QString &n);
+
     QString targetType() const;
     void setTargetType(const QString &code);
 
diff --git a/sources/shiboken6/ApiExtractor/typesystemparser.cpp b/sources/shiboken6/ApiExtractor/typesystemparser.cpp
index a7ce0b3d5..2de95fcdc 100644
--- a/sources/shiboken6/ApiExtractor/typesystemparser.cpp
+++ b/sources/shiboken6/ApiExtractor/typesystemparser.cpp
@@ -1728,6 +1728,8 @@ void TypeSystemParser::applyComplexTypeAttributes(const ConditionalStreamReader
             ctype->setTargetLangName(attributes->takeAt(i).value().toString());
         } else if (name == u"polymorphic-base") {
             ctype->setPolymorphicIdValue(attributes->takeAt(i).value().toString());
+        } else if (name == u"polymorphic-name-function") {
+            ctype->setPolymorphicNameFunction(attributes->takeAt(i).value().toString());
         } else if (name == u"polymorphic-id-expression") {
             ctype->setPolymorphicIdValue(attributes->takeAt(i).value().toString());
         } else if (name == copyableAttribute()) {
diff --git a/sources/shiboken6/doc/typesystem_specifying_types.rst b/sources/shiboken6/doc/typesystem_specifying_types.rst
index 5459046e0..caacc5cb3 100644
--- a/sources/shiboken6/doc/typesystem_specifying_types.rst
+++ b/sources/shiboken6/doc/typesystem_specifying_types.rst
@@ -401,6 +401,8 @@ object-type
              hash-function="..."
              isNull ="yes | no"
              operator-bool="yes | no"
+             polymorphic-id-expression="..."
+             polymorphic-name-function="..."
              private="yes | no"
              qt-register-metatype = "yes | no | base"
              stream="yes | no"
@@ -457,6 +459,19 @@ object-type
     to override the command line setting for generating bool casts
     (see :ref:`bool-cast`).
 
+    The *optional* **polymorphic-id-expression** attribute specifies an
+    expression checking whether a base class pointer is of the matching
+    type. For example, in a ``virtual eventHandler(BaseEvent *e)``
+    function, this is used to construct a Python wrapper matching
+    the derived class (for example, a ``MouseEvent`` or similar).
+
+    The *optional* **polymorphic-name-function** specifies the name of a
+    function returning the type name of a derived class on the base class
+    type entry. Normally, ``typeid(ptr).name()`` is used for this.
+    However, this fails if the type hierarchy does not have virtual functions.
+    In this case, a function is required which typically decides depending
+    on some type enumeration.
+
 interface-type
 ^^^^^^^^^^^^^^
 
diff --git a/sources/shiboken6/generator/shiboken/cppgenerator.cpp b/sources/shiboken6/generator/shiboken/cppgenerator.cpp
index b6dc533c8..a3a1dce63 100644
--- a/sources/shiboken6/generator/shiboken/cppgenerator.cpp
+++ b/sources/shiboken6/generator/shiboken/cppgenerator.cpp
@@ -1633,8 +1633,14 @@ void CppGenerator::writeConverterFunctions(TextStream &s, const AbstractMetaClas
         c << "}\n"
             << "bool changedTypeName = false;\n"
             << "auto tCppIn = reinterpret_cast<const " << typeName << R"( *>(cppIn);
-const char *typeName = typeid(*tCppIn).name();
-auto sbkType = Shiboken::ObjectType::typeForTypeName(typeName);
+const char *typeName = )";
+
+        const QString nameFunc = metaClass->typeEntry()->polymorphicNameFunction();
+        if (nameFunc.isEmpty())
+            c << "typeid(*tCppIn).name();\n";
+        else
+            c << nameFunc << "(tCppIn);\n";
+        c << R"(auto sbkType = Shiboken::ObjectType::typeForTypeName(typeName);
 if (sbkType && Shiboken::ObjectType::hasSpecialCastFunction(sbkType)) {
     typeName = typeNameOf(tCppIn);
     changedTypeName = true;