Do not auto-clean components with live inline components

The inline components do not hold a strong reference to their outer type
because that would be a reference cycle.

Fixes: QTBUG-92236
Change-Id: I6d76a114352653210f0ece6c198cf761d3b4eda1
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit d0d4cc528ba9e3c39c15a2292066dac1d457abd5)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

4 files changed, 57 insertions, 1 deletions

diff --git a/src/qml/qml/qqmlmetatype.cpp b/src/qml/qml/qqmlmetatype.cpp
index 16aafac6d1..f74bec6003 100644
--- a/src/qml/qml/qqmlmetatype.cpp
+++ b/src/qml/qml/qqmlmetatype.cpp
@@ -1405,6 +1405,16 @@ void QQmlMetaType::unregisterType(int typeIndex)
     }
 }
 
+static bool hasActiveInlineComponents(const QQmlTypePrivate *d)
+{
+    for (const QQmlType &ic : qAsConst(d->objectIdToICType)) {
+        const QQmlTypePrivate *icPriv = ic.priv();
+        if (icPriv && icPriv->count() > 1)
+            return true;
+    }
+    return false;
+}
+
 void QQmlMetaType::freeUnusedTypesAndCaches()
 {
     QQmlMetaTypeDataPtr data;
@@ -1419,7 +1429,7 @@ void QQmlMetaType::freeUnusedTypesAndCaches()
         QList<QQmlType>::Iterator it = data->types.begin();
         while (it != data->types.end()) {
             const QQmlTypePrivate *d = (*it).priv();
-            if (d && d->count() == 1) {
+            if (d && d->count() == 1 && !hasActiveInlineComponents(d)) {
                 deletedAtLeastOneType = true;
 
                 removeQQmlTypePrivate(data->idToType, d);
diff --git a/tests/auto/qml/qqmllanguage/data/Tab1.qml b/tests/auto/qml/qqmllanguage/data/Tab1.qml
new file mode 100644
index 0000000000..e1cd6d8c34
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/Tab1.qml
@@ -0,0 +1,9 @@
+import QtQuick 2.15
+
+Item {
+    component LeftTab: Item {
+    }
+
+    component RightTab: Item {
+    }
+}
diff --git a/tests/auto/qml/qqmllanguage/data/bareInline.qml b/tests/auto/qml/qqmllanguage/data/bareInline.qml
new file mode 100644
index 0000000000..cb79021250
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/bareInline.qml
@@ -0,0 +1,9 @@
+import QtQuick 2.9
+
+Item {
+    width: 800
+    height: 600
+    visible: true
+
+    Tab1.RightTab {}
+}
diff --git a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
index 3b527a8f50..41fb80d8ed 100644
--- a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
+++ b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
@@ -49,6 +49,7 @@
 #include <private/qqmlscriptstring_p.h>
 #include <private/qqmlvmemetaobject_p.h>
 #include <private/qqmlcomponent_p.h>
+#include <private/qqmltype_p_p.h>
 
 #include "testtypes.h"
 #include "testhttpserver.h"
@@ -337,6 +338,7 @@ private slots:
     void arrayToContainer();
     void qualifiedScopeInCustomParser();
     void accessNullPointerPropertyCache();
+    void bareInlineComponent();
 
     void checkUncreatableNoReason();
 
@@ -6248,6 +6250,32 @@ void tst_qqmllanguage::qtbug_85615()
     QCOMPARE(o->property("resultNull").metaType(), QMetaType(QMetaType::Nullptr));
 }
 
+void tst_qqmllanguage::bareInlineComponent()
+{
+    QQmlEngine engine;
+
+    QQmlComponent c(&engine, testFileUrl("bareInline.qml"));
+    QVERIFY2(c.isReady(), qPrintable(c.errorString()));
+    QScopedPointer<QObject> o(c.create());
+    QVERIFY(!o.isNull());
+
+    QQmlMetaType::freeUnusedTypesAndCaches();
+
+    bool tab1Found = false;
+    const auto types = QQmlMetaType::qmlTypes();
+    for (const QQmlType &type : types) {
+        if (type.elementName() == QStringLiteral("Tab1")) {
+            QVERIFY(type.module().isEmpty());
+            tab1Found = true;
+            const auto ics = type.priv()->objectIdToICType;
+            QVERIFY(ics.size() > 0);
+            for (const QQmlType &ic : ics)
+                QVERIFY(ic.containingType() == type);
+        }
+    }
+    QVERIFY(tab1Found);
+}
+
 QTEST_MAIN(tst_qqmllanguage)
 
 #include "tst_qqmllanguage.moc"