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, 11 insertions, 0 deletions

diff --git a/src/qml/qml/qqmlimport.cpp b/src/qml/qml/qqmlimport.cpp
index 0bd7317470..ccd287e1b6 100644
--- a/src/qml/qml/qqmlimport.cpp
+++ b/src/qml/qml/qqmlimport.cpp
@@ -471,6 +471,17 @@ void findCompositeSingletons(const QQmlImportNamespace &set, QList<QQmlImports::
                 resultList.append(ref);
             }
         }
+
+        if (QQmlTypeModule *module = QQmlMetaType::typeModule(import->uri, import->majversion)) {
+            module->walkCompositeSingletons([&resultList, &set](const QQmlType &singleton) {
+                QQmlImports::CompositeSingletonReference ref;
+                ref.typeName = singleton.elementName();
+                ref.prefix = set.prefix;
+                ref.majorVersion = singleton.majorVersion();
+                ref.minorVersion = singleton.minorVersion();
+                resultList.append(ref);
+            });
+        }
     }
 }