Fix qml cache invalidation when changing dependent C++ registered QML singletons

When a qml file uses a qml singleton, we need to reliably detect when
the singleton changes and re-generate the cache of the qml file using
it. This is a scenario covered and fixed by commit
5b94de09cc738837d1539e28b3c0dccd17c18d29, with the exception that
currently QML singletons registered via qmlRegisterSingleton were not
added to the list of dependent singletons for a qml file. We can fix
this by extending findCompositeSingletons() to also cover the singletons
that do not originate from a qmldir file.

[ChangeLog][Qt][Qml] Fixed bug where sometimes changes to a qml
singleton would not propagate to the users or cause crashes.

Task-number: QTBUG-62243
Change-Id: I16c3d9ba65fd82e898a29b946c341907751135a9
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/qml/qml/qqmlmetatype.cpp b/src/qml/qml/qqmlmetatype.cpp
index 5bbc250d5e..8f5d11a96f 100644
--- a/src/qml/qml/qqmlmetatype.cpp
+++ b/src/qml/qml/qqmlmetatype.cpp
@@ -1258,6 +1258,18 @@ QQmlType QQmlTypeModule::type(const QV4::String *name, int minor) const
     return QQmlType();
 }
 
+void QQmlTypeModule::walkCompositeSingletons(const std::function<void(const QQmlType &)> &callback) const
+{
+    QMutexLocker lock(metaTypeDataLock());
+    for (auto typeCandidates = d->typeHash.begin(), end = d->typeHash.end();
+         typeCandidates != end; ++typeCandidates) {
+        for (auto type: typeCandidates.value()) {
+            if (type->regType == QQmlType::CompositeSingletonType)
+                callback(QQmlType(type));
+        }
+    }
+}
+
 QQmlTypeModuleVersion::QQmlTypeModuleVersion()
 : m_module(0), m_minor(0)
 {