From e13a30f00fc77e0182db9968ede9574d15029da8 Mon Sep 17 00:00:00 2001
From: David Edmundson <kde@davidedmundson.co.uk>
Date: Mon, 18 Mar 2024 10:20:29 +0000
Subject: [PATCH] effects: Do not take ownership of QuickEffect::delegate

QuickEffect::setDelegate is exposed QML API.

The lifespan of assigned objects is therefore managed by the QML engine,
and we should be watching for deletion not actually deleting it.
---
 src/effect/quickeffect.cpp              | 11 ++++++-----
 src/plugins/overview/overvieweffect.cpp |  2 +-
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/effect/quickeffect.cpp b/src/effect/quickeffect.cpp
index 4fa0ab023b..e8a6061c4b 100644
--- a/src/effect/quickeffect.cpp
+++ b/src/effect/quickeffect.cpp
@@ -65,7 +65,7 @@ public:
     }
     bool isItemOnScreen(QQuickItem *item, Output *screen) const;
 
-    std::unique_ptr<QQmlComponent> delegate;
+    QPointer<QQmlComponent> delegate;
     QUrl source;
     std::map<Output *, std::unique_ptr<QQmlContext>> contexts;
     std::map<Output *, std::unique_ptr<QQmlIncubator>> incubators;
@@ -248,7 +248,7 @@ void QuickSceneEffect::setSource(const QUrl &url)
     }
     if (d->source != url) {
         d->source = url;
-        d->delegate.reset();
+        d->delegate.clear();
     }
 }
 
@@ -265,7 +265,7 @@ void QuickSceneEffect::setDelegate(QQmlComponent *delegate)
     }
     if (d->delegate.get() != delegate) {
         d->source = QUrl();
-        d->delegate.reset(delegate);
+        d->delegate = delegate;
         Q_EMIT delegateChanged();
     }
 }
@@ -472,11 +472,12 @@ void QuickSceneEffect::startInternal()
             return;
         }
 
-        d->delegate = std::make_unique<QQmlComponent>(effects->qmlEngine());
+        d->delegate = new QQmlComponent(effects->qmlEngine(), this);
         d->delegate->loadUrl(d->source);
+
         if (d->delegate->isError()) {
             qWarning().nospace() << "Failed to load " << d->source << ": " << d->delegate->errors();
-            d->delegate.reset();
+            d->delegate.clear();
             return;
         }
         Q_EMIT delegateChanged();
diff --git a/src/plugins/overview/overvieweffect.cpp b/src/plugins/overview/overvieweffect.cpp
index 58ccb04ec0..bb71edac27 100644
--- a/src/plugins/overview/overvieweffect.cpp
+++ b/src/plugins/overview/overvieweffect.cpp
@@ -158,7 +158,7 @@ OverviewEffect::OverviewEffect()
     OverviewConfig::instance(effects->config());
     reconfigure(ReconfigureAll);
 
-    auto delegate = new QQmlComponent(effects->qmlEngine());
+    auto delegate = new QQmlComponent(effects->qmlEngine(), this);
     connect(delegate, &QQmlComponent::statusChanged, this, [delegate]() {
         if (delegate->isError()) {
             qWarning() << "Failed to load overview:" << delegate->errorString();