layout: fix crash on monitor reconnect due to stale workspace state

Guard against null/expired workspace and monitor pointers during layout recalculation triggered by arrangeMonitors after sleep/wake.

3 files changed, 18 insertions, 3 deletions

diff --git a/src/layout/algorithm/Algorithm.cpp b/src/layout/algorithm/Algorithm.cpp
index cfb5b7e3..b83a03a3 100644
--- a/src/layout/algorithm/Algorithm.cpp
+++ b/src/layout/algorithm/Algorithm.cpp
@@ -105,7 +105,10 @@ void CAlgorithm::recalculate() {
     m_floating->recalculate();
 
     const auto PWORKSPACE = m_space->workspace();
-    const auto PMONITOR   = PWORKSPACE->m_monitor;
+    if (!PWORKSPACE)
+        return;
+
+    const auto PMONITOR = PWORKSPACE->m_monitor;
 
     if (PWORKSPACE->m_hasFullscreenWindow && PMONITOR) {
         // massive hack from the fullscreen func
diff --git a/src/layout/algorithm/tiled/scrolling/ScrollingAlgorithm.cpp b/src/layout/algorithm/tiled/scrolling/ScrollingAlgorithm.cpp
index 7b9a1752..e3f326e8 100644
--- a/src/layout/algorithm/tiled/scrolling/ScrollingAlgorithm.cpp
+++ b/src/layout/algorithm/tiled/scrolling/ScrollingAlgorithm.cpp
@@ -422,7 +422,8 @@ SP<SColumnData> SScrollingData::atCenter() {
 }
 
 void SScrollingData::recalculate(bool forceInstant) {
-    if (!algorithm->m_parent->space()->workspace() || algorithm->m_parent->space()->workspace()->m_hasFullscreenWindow)
+    if (!algorithm->m_parent || !algorithm->m_parent->space() || !algorithm->m_parent->space()->workspace() || !algorithm->m_parent->space()->workspace()->m_monitor ||
+        algorithm->m_parent->space()->workspace()->m_hasFullscreenWindow)
         return;
 
     static const auto PFSONONE = CConfigValue<Hyprlang::INT>("scrolling:fullscreen_on_one_column");
@@ -1505,6 +1506,9 @@ eScrollDirection CScrollingAlgorithm::getDynamicDirection() {
 }
 
 CBox CScrollingAlgorithm::usableArea() {
+    if (!m_parent || !m_parent->space())
+        return {};
+
     CBox box = m_parent->space()->workArea();
 
     // doesn't matter, this happens when this algo is about to be destroyed
diff --git a/src/layout/space/Space.cpp b/src/layout/space/Space.cpp
index db3925f6..a02ba517 100644
--- a/src/layout/space/Space.cpp
+++ b/src/layout/space/Space.cpp
@@ -21,8 +21,16 @@ CSpace::CSpace(PHLWORKSPACE parent) : m_parent(parent) {
 
     // NOLINTNEXTLINE
     m_geomUpdateCallback = Event::bus()->m_events.monitor.layoutChanged.listen([this] {
+        // During monitor disconnect/reconnect (e.g. sleep/wake), some workspaces
+        // may have stale or null monitors. Guard against that to avoid crashing
+        // when recalculating layout for workspaces mid-migration.
+        if (!m_parent || !m_parent->m_monitor)
+            return;
+
         recheckWorkArea();
-        m_algorithm->recalculate();
+
+        if (m_algorithm)
+            m_algorithm->recalculate();
     });
 }