From bd5c566399bb8f1432c4bd94f73be71cefad8675 Mon Sep 17 00:00:00 2001
From: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
Date: Wed, 22 Nov 2023 09:59:42 +0200
Subject: [PATCH] plugins/screentransform: Avoid mangling with opengl context
 when a screen is removed

For the most part, the screen transform effect is inactive. So if a
screen is removed, it's likely that m_states contains no entry for it.
---
 src/plugins/screentransform/screentransform.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/plugins/screentransform/screentransform.cpp b/src/plugins/screentransform/screentransform.cpp
index dea933774a..6bbd6a2f2a 100644
--- a/src/plugins/screentransform/screentransform.cpp
+++ b/src/plugins/screentransform/screentransform.cpp
@@ -116,9 +116,10 @@ void ScreenTransformEffect::addScreen(Output *screen)
 
 void ScreenTransformEffect::removeScreen(Output *screen)
 {
-    effects->makeOpenGLContextCurrent();
-    m_states.remove(screen);
-    effects->doneOpenGLContextCurrent();
+    if (auto it = m_states.find(screen); it != m_states.end()) {
+        effects->makeOpenGLContextCurrent();
+        m_states.erase(it);
+    }
 }
 
 void ScreenTransformEffect::prePaintScreen(ScreenPrePaintData &data, std::chrono::milliseconds presentTime)