fix: migrate windows and layer surfaces on primary output hot-unplug

src/core/layersurfacecontainer.cpp

@@ -64,19 +64,26 @@ void LayerSurfaceContainer::removeOutput(Output *output)
     Q_ASSERT(container);
     m_surfaceContainers.removeOne(container);
 
+    OutputLayerSurfaceContainer *targetContainer = m_surfaceContainers.isEmpty()
+        ? nullptr
+        : m_surfaceContainers.first();
+
     const auto surfaces = container->surfaces();
     for (SurfaceWrapper *surface : surfaces) {
-        auto layerSurface = qobject_cast<WLayerSurface *>(surface->shellSurface());
-        Q_ASSERT(layerSurface);
-        // Needs to be moved to the new primary output
-        if (!layerSurface->output() && rootContainer()->primaryOutput()) {
-            container->removeSurface(surface);
-            addSurfaceToContainer(surface);
+        container->removeSurface(surface);
+        if (targetContainer) {
+            targetContainer->addSurface(surface);
         } else {
-            layerSurface->closed();
+            auto layerSurface = qobject_cast<WLayerSurface *>(surface->shellSurface());
+            if (layerSurface)
+                layerSurface->closed();
         }
     }
 
+    if (targetContainer) {
+        targetContainer->output()->arrangeLayerSurfaces();
+    }
+
     container->deleteLater();
 }
 

src/core/rootsurfacecontainer.cpp

@@ -149,6 +149,13 @@ void RootSurfaceContainer::removeOutput(Output *output)
         }
     }
 
+    // Save positions of remaining outputs before layout removal
+    QMap<Output *, QPointF> oldPositions;
+    for (auto o : outputs()) {
+        if (o != output)
+            oldPositions[o] = o->outputItem()->position();
+    }
+
     m_outputLayout->remove(output->output());
     if (m_primaryOutput == output) {
         const auto outputs = m_outputLayout->outputs();
@@ -158,6 +165,28 @@ void RootSurfaceContainer::removeOutput(Output *output)
         }
     }
 
+    // Correct positions of surfaces on remaining outputs after layout change
+    for (auto o : outputs()) {
+        if (o == output)
+            continue;
+        auto it = oldPositions.find(o);
+        if (it == oldPositions.end())
+            continue;
+        QPointF delta = o->outputItem()->position() - it.value();
+        if (!delta.isNull()) {
+            for (auto *surface : surfaces()) {
+                if (surface->type() != SurfaceWrapper::Type::Layer && surface->ownsOutput() == o) {
+                    surface->setPosition(surface->position() + delta);
+                    if (surface->type() == SurfaceWrapper::Type::XdgToplevel) {
+                        auto normalGeo = surface->normalGeometry();
+                        normalGeo.moveTopLeft(normalGeo.topLeft() + delta);
+                        surface->moveNormalGeometryInOutput(normalGeo.topLeft());
+                    }
+                }
+            }
+        }
+    }
+
     // ensure cursor within output
     const auto outputPos = output->outputItem()->position();
     if (output->geometry().contains(m_cursor->position()) && m_primaryOutput) {

src/output/output.h

@@ -90,6 +90,7 @@ class Output : public SurfaceListModel
     void adjustToOutputBounds(QPointF &pos,
                               const QRectF &normalGeo,
                               const QRectF &outputRect) const;
+    void arrangeLayerSurfaces();
 
 Q_SIGNALS:
     void exclusiveZoneChanged();
@@ -110,7 +111,6 @@ public Q_SLOTS:
     void setExclusiveZone(Qt::Edge edge, QObject *object, int value);
     bool removeExclusiveZone(QObject *object);
     void arrangeLayerSurface(SurfaceWrapper *surface);
-    void arrangeLayerSurfaces();
     void arrangeNonLayerSurface(SurfaceWrapper *surface, const QSizeF &sizeDiff);
     void arrangePopupSurface(SurfaceWrapper *surface);
     void arrangeNonLayerSurfaces();

src/output/outputlifecyclemanager.cpp

@@ -59,6 +59,23 @@ void OutputLifecycleManager::switchPrimaryOutput(Output *from,
     m_rootContainer->moveSurfacesToOutput(surfaces, to, from);
 }
 
+void OutputLifecycleManager::migrateSurfacesToNewPrimary(Output *removedOutput,
+                                                         const QList<SurfaceWrapper *> &surfaces)
+{
+    // NOTE: This must be called while removedOutput's Output item still has valid position
+    // data. The call chain is: Helper::onOutputRemoved -> removeOutput (switches primary)
+    // -> onScreenRemoved -> migrateSurfacesToNewPrimary. At this point the removed output
+    // has been removed from the layout, but the Output object (and its item position) still
+    // exists because `delete o` happens after onScreenRemoved returns.
+    if (!m_rootContainer || surfaces.isEmpty())
+        return;
+
+    auto newPrimary = m_rootContainer->primaryOutput();
+    if (newPrimary) {
+        m_rootContainer->moveSurfacesToOutput(surfaces, newPrimary, removedOutput);
+    }
+}
+
 void OutputLifecycleManager::onScreenAdded(Output *output)
 {
     if (!output || !m_configState)
@@ -91,11 +108,8 @@ void OutputLifecycleManager::onScreenRemoved(Output *output,
         markScreenAsPrimaryIntent(output);
     }
 
-    if (!isCurrentPrimary && !wasPrimaryBeforeRemoval) {
-        auto primaryOutput = m_rootContainer->primaryOutput();
-        if (primaryOutput) {
-            m_rootContainer->moveSurfacesToOutput(surfaces, primaryOutput, output);
-        }
+    if (!isCurrentPrimary) {
+        migrateSurfacesToNewPrimary(output, surfaces);
     }
 }
 
@@ -120,10 +134,7 @@ void OutputLifecycleManager::onScreenDisabled(Output *output,
             switchPrimaryOutput(output, nextPrimary, surfaces);
         }
     } else if (!isCurrentPrimary) {
-        auto primaryOutput = m_rootContainer->primaryOutput();
-        if (primaryOutput) {
-            m_rootContainer->moveSurfacesToOutput(surfaces, primaryOutput, output);
-        }
+        migrateSurfacesToNewPrimary(output, surfaces);
     }
 }
 

src/output/outputlifecyclemanager.h

@@ -1,4 +1,4 @@
-// Copyright (C) 2025 UnionTech Software Technology Co., Ltd.
+// Copyright (C) 2025-2026 UnionTech Software Technology Co., Ltd.
 // SPDX-License-Identifier: Apache-2.0 OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
 #pragma once
@@ -32,6 +32,7 @@ class OutputLifecycleManager : public QObject {
     void onScreenRemoved(Output *output, const QList<SurfaceWrapper *> &surfaces);
     void onScreenDisabled(Output *output, const QList<SurfaceWrapper *> &surfaces);
     void onScreenEnabled(Output *output);
+    void migrateSurfacesToNewPrimary(Output *removedOutput, const QList<SurfaceWrapper *> &surfaces);
     void setMode(Mode mode) {
         m_mode = mode;
     }