fix: handle fullscreen windows on special workspaces (#12851)

* fix: handle fullscreen windows on special workspaces

inFullscreenMode() only checked m_activeWorkspace, missing fullscreen
windows on special workspaces. This caused crashes and incorrect
behavior when fullscreen windows were on special workspaces.

Changes:
- inFullscreenMode() now checks special workspace first since it
  renders on top of regular workspaces
- Added getFullscreenWindow() helper to safely get fullscreen window
  from either active or special workspace
- Updated callers (shouldSkipScheduleFrameOnMouseEvent, Renderer,
  getFSImageDescription) to use the new helper
- Reset m_aboveFullscreen for layer surfaces when opening, closing,
  or stealing special workspaces between monitors

* test: add special workspace fullscreen detection tests

Add tests for the new special workspace fullscreen handling introduced
in the previous commit. The tests cover:

1. Fullscreen detection on special workspace - verifies that a window
   made fullscreen on a special workspace is correctly detected

2. Special workspace fullscreen precedence - verifies that when both
   regular and special workspaces have fullscreen windows, the special
   workspace window can be focused when the special workspace is opened

3. Toggle special workspace behavior - verifies that toggling the
   special workspace off properly hides it and returns focus to the
   regular workspace's fullscreen window

These tests exercise the key code paths modified in the fix:
- inFullscreenMode() checking special workspace first
- getFullscreenWindow() helper returning correct window
- Layer surface m_aboveFullscreen reset on special workspace toggle

4 files changed, 126 insertions, 7 deletions

diff --git a/hyprtester/src/tests/main/workspaces.cpp b/hyprtester/src/tests/main/workspaces.cpp
index c1b9690a..036ddaf5 100644
--- a/hyprtester/src/tests/main/workspaces.cpp
+++ b/hyprtester/src/tests/main/workspaces.cpp
@@ -20,6 +20,91 @@ using namespace Hyprutils::Utils;
 #define UP CUniquePointer
 #define SP CSharedPointer
 
+static bool testSpecialWorkspaceFullscreen() {
+    NLog::log("{}Testing special workspace fullscreen detection", Colors::YELLOW);
+
+    CScopeGuard guard = {[&]() {
+        NLog::log("{}Cleaning up special workspace fullscreen test", Colors::YELLOW);
+        // Close special workspace if open
+        auto monitors = getFromSocket("/monitors");
+        if (monitors.contains("(special:test_fs_special)") && !monitors.contains("special workspace: 0 ()"))
+            getFromSocket("/dispatch togglespecialworkspace test_fs_special");
+        Tests::killAllWindows();
+        OK(getFromSocket("/reload"));
+    }};
+
+    getFromSocket("/dispatch workspace 1");
+    EXPECT(Tests::windowCount(), 0);
+
+    NLog::log("{}Test 1: Fullscreen detection on special workspace", Colors::YELLOW);
+
+    OK(getFromSocket("/dispatch workspace special:test_fs_special"));
+
+    if (!Tests::spawnKitty("kitty_special"))
+        return false;
+
+    {
+        auto str = getFromSocket("/activewindow");
+        EXPECT_CONTAINS(str, "class: kitty_special");
+        EXPECT_CONTAINS(str, "(special:test_fs_special)");
+    }
+
+    OK(getFromSocket("/dispatch fullscreen 0"));
+
+    {
+        auto str = getFromSocket("/activewindow");
+        EXPECT_CONTAINS(str, "fullscreen: 2");
+    }
+
+    {
+        auto str = getFromSocket("/monitors");
+        EXPECT_CONTAINS(str, "(special:test_fs_special)");
+    }
+
+    NLog::log("{}Test 2: Special workspace fullscreen precedence", Colors::YELLOW);
+
+    // Close special workspace before spawning on regular workspace
+    OK(getFromSocket("/dispatch togglespecialworkspace test_fs_special"));
+    getFromSocket("/dispatch workspace 1");
+
+    if (!Tests::spawnKitty("kitty_regular"))
+        return false;
+
+    OK(getFromSocket("/dispatch fullscreen 0"));
+
+    {
+        auto str = getFromSocket("/activewindow");
+        EXPECT_CONTAINS(str, "class: kitty_regular");
+        EXPECT_CONTAINS(str, "fullscreen: 2");
+    }
+
+    OK(getFromSocket("/dispatch togglespecialworkspace test_fs_special"));
+    OK(getFromSocket("/dispatch focuswindow class:kitty_special"));
+
+    {
+        auto str = getFromSocket("/activewindow");
+        EXPECT_CONTAINS(str, "class: kitty_special");
+    }
+
+    NLog::log("{}Test 3: Toggle special workspace hides it", Colors::YELLOW);
+
+    OK(getFromSocket("/dispatch togglespecialworkspace test_fs_special"));
+    OK(getFromSocket("/dispatch focuswindow class:kitty_regular"));
+
+    {
+        auto str = getFromSocket("/activewindow");
+        EXPECT_CONTAINS(str, "class: kitty_regular");
+        EXPECT_CONTAINS(str, "fullscreen: 2");
+    }
+
+    {
+        auto str = getFromSocket("/monitors");
+        EXPECT_CONTAINS(str, "special workspace: 0 ()");
+    }
+
+    return true;
+}
+
 static bool testAsymmetricGaps() {
     NLog::log("{}Testing asymmetric gap splits", Colors::YELLOW);
     {
@@ -449,6 +534,8 @@ static bool test() {
     NLog::log("{}Killing all windows", Colors::YELLOW);
     Tests::killAllWindows();
 
+    testSpecialWorkspaceFullscreen();
+
     testAsymmetricGaps();
 
     NLog::log("{}Expecting 0 windows", Colors::YELLOW);
diff --git a/src/helpers/Monitor.cpp b/src/helpers/Monitor.cpp
index 5069f5d8..397df6ee 100644
--- a/src/helpers/Monitor.cpp
+++ b/src/helpers/Monitor.cpp
@@ -1026,8 +1026,8 @@ bool CMonitor::shouldSkipScheduleFrameOnMouseEvent() {
     static auto PMINRR   = CConfigValue<Hyprlang::INT>("cursor:min_refresh_rate");
 
     // skip scheduling extra frames for fullsreen apps with vrr
-    const bool shouldSkip = inFullscreenMode() && (*PNOBREAK == 1 || (*PNOBREAK == 2 && m_activeWorkspace->getFullscreenWindow()->getContentType() == CONTENT_TYPE_GAME)) &&
-        m_output->state->state().adaptiveSync;
+    const auto FS_WINDOW  = getFullscreenWindow();
+    const bool shouldSkip = FS_WINDOW && (*PNOBREAK == 1 || (*PNOBREAK == 2 && FS_WINDOW->getContentType() == CONTENT_TYPE_GAME)) && m_output->state->state().adaptiveSync;
 
     // keep requested minimum refresh rate
     if (shouldSkip && *PMINRR && m_lastPresentationTimer.getMillis() > 1000.0f / *PMINRR) {
@@ -1357,6 +1357,12 @@ void CMonitor::setSpecialWorkspace(const PHLWORKSPACE& pWorkspace) {
             g_pDesktopAnimationManager->startAnimation(m_activeSpecialWorkspace, CDesktopAnimationManager::ANIMATION_TYPE_OUT, false);
             g_pEventManager->postEvent(SHyprIPCEvent{"activespecial", "," + m_name});
             g_pEventManager->postEvent(SHyprIPCEvent{"activespecialv2", ",," + m_name});
+
+            // Reset layer surface state when closing special workspace
+            for (auto const& ls : g_pCompositor->m_layers) {
+                if (ls->m_monitor == m_self)
+                    ls->m_aboveFullscreen = false;
+            }
         }
         m_activeSpecialWorkspace.reset();
 
@@ -1396,6 +1402,12 @@ void CMonitor::setSpecialWorkspace(const PHLWORKSPACE& pWorkspace) {
         g_pEventManager->postEvent(SHyprIPCEvent{"activespecial", "," + PMWSOWNER->m_name});
         g_pEventManager->postEvent(SHyprIPCEvent{"activespecialv2", ",," + PMWSOWNER->m_name});
 
+        // Reset layer surfaces on the old monitor when special workspace is stolen
+        for (auto const& ls : g_pCompositor->m_layers) {
+            if (ls->m_monitor == PMWSOWNER)
+                ls->m_aboveFullscreen = false;
+        }
+
         const auto PACTIVEWORKSPACE = PMWSOWNER->m_activeWorkspace;
         g_pDesktopAnimationManager->setFullscreenFadeAnimation(PACTIVEWORKSPACE,
                                                                PACTIVEWORKSPACE && PACTIVEWORKSPACE->m_hasFullscreenWindow ? CDesktopAnimationManager::ANIMATION_TYPE_IN :
@@ -1409,6 +1421,12 @@ void CMonitor::setSpecialWorkspace(const PHLWORKSPACE& pWorkspace) {
     m_activeSpecialWorkspace            = pWorkspace;
     m_activeSpecialWorkspace->m_visible = true;
 
+    // Reset layer surface state when opening special workspace
+    for (auto const& ls : g_pCompositor->m_layers) {
+        if (ls->m_monitor == m_self)
+            ls->m_aboveFullscreen = false;
+    }
+
     if (POLDSPECIAL)
         POLDSPECIAL->m_events.activeChanged.emit();
 
@@ -2017,16 +2035,28 @@ bool CMonitor::inHDR() {
 }
 
 bool CMonitor::inFullscreenMode() {
+    // Check special workspace first since it renders on top of regular workspaces
+    if (m_activeSpecialWorkspace && m_activeSpecialWorkspace->m_hasFullscreenWindow && m_activeSpecialWorkspace->m_fullscreenMode == FSMODE_FULLSCREEN)
+        return true;
     return m_activeWorkspace && m_activeWorkspace->m_hasFullscreenWindow && m_activeWorkspace->m_fullscreenMode == FSMODE_FULLSCREEN;
 }
 
+PHLWINDOW CMonitor::getFullscreenWindow() {
+    // Check special workspace first since it renders on top of regular workspaces
+    if (m_activeSpecialWorkspace && m_activeSpecialWorkspace->m_hasFullscreenWindow && m_activeSpecialWorkspace->m_fullscreenMode == FSMODE_FULLSCREEN)
+        return m_activeSpecialWorkspace->getFullscreenWindow();
+    if (m_activeWorkspace && m_activeWorkspace->m_hasFullscreenWindow && m_activeWorkspace->m_fullscreenMode == FSMODE_FULLSCREEN)
+        return m_activeWorkspace->getFullscreenWindow();
+    return nullptr;
+}
+
 std::optional<NColorManagement::PImageDescription> CMonitor::getFSImageDescription() {
     if (!inFullscreenMode())
         return {};
 
-    const auto FS_WINDOW = m_activeWorkspace->getFullscreenWindow();
+    const auto FS_WINDOW = getFullscreenWindow();
     if (!FS_WINDOW)
-        return {}; // should be unreachable
+        return {};
 
     const auto ROOT_SURF = FS_WINDOW->wlSurface()->resource();
     const auto SURF      = ROOT_SURF->findWithCM();
diff --git a/src/helpers/Monitor.hpp b/src/helpers/Monitor.hpp
index 98d672e6..339497a5 100644
--- a/src/helpers/Monitor.hpp
+++ b/src/helpers/Monitor.hpp
@@ -327,8 +327,10 @@ class CMonitor {
 
     bool        inHDR();
 
-    /// Has an active workspace with a real fullscreen window
-    bool                                               inFullscreenMode();
+    /// Has an active workspace with a real fullscreen window (includes special workspace)
+    bool inFullscreenMode();
+    /// Get fullscreen window from active or special workspace
+    PHLWINDOW                                          getFullscreenWindow();
     std::optional<NColorManagement::PImageDescription> getFSImageDescription();
 
     bool                                               needsCM();
diff --git a/src/render/Renderer.cpp b/src/render/Renderer.cpp
index 1aa85f15..6a24c0d3 100644
--- a/src/render/Renderer.cpp
+++ b/src/render/Renderer.cpp
@@ -1567,7 +1567,7 @@ bool CHyprRenderer::commitPendingAndDoExplicitSync(PHLMONITOR pMonitor) {
     const bool  configuredHDR = (pMonitor->m_cmType == NCMType::CM_HDR_EDID || pMonitor->m_cmType == NCMType::CM_HDR);
     bool        wantHDR       = configuredHDR;
 
-    const auto  FS_WINDOW = pMonitor->inFullscreenMode() ? pMonitor->m_activeWorkspace->getFullscreenWindow() : nullptr;
+    const auto  FS_WINDOW = pMonitor->getFullscreenWindow();
 
     if (pMonitor->supportsHDR()) {
         // HDR metadata determined by