Improve Qt initialization order hack

In CppGenerator::finishGeneration(), the code tried to reorder the
classlist such that the initialization of QMetaObject is written
before the initialization of QObject by re-inserting the QMetaObject
class entry in front of QObject. This does not consider the dependency
of QMetaObject::Connection on QMetaObject and worked only by
coincidence since the old parser did not recognize
QMetaObject::Connection as an inner class due to it being
forward-declared.

With the Clang-based parser, which recognizes this, the initialization
for QMetaObject::Connection would be called before the initialization
of QMetaObject, causing a crash.

Fix this by making it possible to pass additional dependencies
as pairs of QString to the topological sorting functions, which
then generate the correct sequence.

Task-number: PYSIDE-323
Change-Id: Ia915b47131d57e71df366876a1a9f317cfd8d497
Reviewed-by: Christian Tismer <tismer@stackless.com>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

3 files changed, 17 insertions, 11 deletions

diff --git a/generator/generator.cpp b/generator/generator.cpp
index 20a7e9c..bde69f1 100644
--- a/generator/generator.cpp
+++ b/generator/generator.cpp
@@ -177,9 +177,9 @@ AbstractMetaClassList Generator::classes() const
     return m_d->apiextractor->classes();
 }
 
-AbstractMetaClassList Generator::classesTopologicalSorted() const
+AbstractMetaClassList Generator::classesTopologicalSorted(const Dependencies &additionalDependencies) const
 {
-    return m_d->apiextractor->classesTopologicalSorted();
+    return m_d->apiextractor->classesTopologicalSorted(additionalDependencies);
 }
 
 AbstractMetaFunctionList Generator::globalFunctions() const
diff --git a/generator/generator.h b/generator/generator.h
index e570d8b..ac78d62 100644
--- a/generator/generator.h
+++ b/generator/generator.h
@@ -30,6 +30,7 @@
 #define GENERATOR_H
 
 #include <abstractmetalang_typedefs.h>
+#include <dependency.h>
 #include <QtCore/QObject>
 #include <QtCore/QSharedPointer>
 #include <QtCore/QTextStream>
@@ -120,7 +121,7 @@ public:
     ///
     /// The classes are ordered such that derived classes appear later in the list than
     /// their parent classes.
-    AbstractMetaClassList classesTopologicalSorted() const;
+    AbstractMetaClassList classesTopologicalSorted(const Dependencies &additionalDependencies = Dependencies()) const;
 
     /// Returns all global functions found by APIExtractor
     AbstractMetaFunctionList globalFunctions() const;
diff --git a/generator/shiboken2/cppgenerator.cpp b/generator/shiboken2/cppgenerator.cpp
index efdcbaf..74c061c 100644
--- a/generator/shiboken2/cppgenerator.cpp
+++ b/generator/shiboken2/cppgenerator.cpp
@@ -4691,6 +4691,9 @@ void CppGenerator::writeGetattroFunction(QTextStream& s, const AbstractMetaClass
     s << '}' << endl;
 }
 
+static inline QString qObjectClassName() { return QStringLiteral("QObject"); }
+static inline QString qMetaObjectClassName() { return QStringLiteral("QMetaObject"); }
+
 bool CppGenerator::finishGeneration()
 {
     //Generate CPython wrapper file
@@ -4727,14 +4730,16 @@ bool CppGenerator::finishGeneration()
 
     //this is a temporary solution before new type revison implementation
     //We need move QMetaObject register before QObject
-    AbstractMetaClassList lst = classesTopologicalSorted();
-    AbstractMetaClass* klassQObject = lst.findClass(QLatin1String("QObject"));
-    AbstractMetaClass* klassQMetaObject = lst.findClass(QLatin1String("QMetaObject"));
-    if (klassQObject && klassQMetaObject) {
-        lst.removeAll(klassQMetaObject);
-        int indexOf = lst.indexOf(klassQObject);
-        lst.insert(indexOf, klassQMetaObject);
-    }
+    Dependencies additionalDependencies;
+    const AbstractMetaClassList &allClasses = classes();
+    if (allClasses.findClass(qObjectClassName()) != Q_NULLPTR
+        && allClasses.findClass(qMetaObjectClassName()) != Q_NULLPTR) {
+        Dependency dependency;
+        dependency.parent = qMetaObjectClassName();
+        dependency.child = qObjectClassName();
+        additionalDependencies.append(dependency);
+    }
+    const AbstractMetaClassList lst = classesTopologicalSorted(additionalDependencies);
 
     foreach (const AbstractMetaClass* cls, lst) {
         if (!shouldGenerate(cls))