Ensure that QOpenGLMultiGroupSharedResources are cleaned up

When a GL context group is destroyed, all multi-group shared
resources associated with the group should be cleaned up.
Otherwise we could get a double deletion in the resource's
destructor, because it still retained a pointer to the
deleted group.

The missing cleanup resulted in a crash when the global
static qt_gl_functions_resource was destroyed, first seen
in the tst_examples autotest in qtdeclarative. It possibly
didn't manifest before because it's event loop-dependent
(the contexts are deleted via deleteLater()).

Change-Id: I6b1e0bfdfbbb2bff8e795f545e680fcdfa094768
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

1 files changed, 23 insertions, 0 deletions

diff --git a/tests/auto/gui/qopengl/tst_qopengl.cpp b/tests/auto/gui/qopengl/tst_qopengl.cpp
index 479c1c8e2e..a3e0cf4fba 100644
--- a/tests/auto/gui/qopengl/tst_qopengl.cpp
+++ b/tests/auto/gui/qopengl/tst_qopengl.cpp
@@ -42,6 +42,7 @@
 
 #include <QtGui/private/qopenglcontext_p.h>
 #include <QtGui/QOpenGLFramebufferObject>
+#include <QtGui/QOpenGLFunctions>
 #include <QtGui/QOpenGLPaintDevice>
 #include <QtGui/QPainter>
 #include <QtGui/QScreen>
@@ -55,6 +56,7 @@ Q_OBJECT
 
 private slots:
     void sharedResourceCleanup();
+    void multiGroupSharedResourceCleanup();
     void fboSimpleRendering();
     void fboRendering();
     void fboHandleNulledAfterContextDestroyed();
@@ -172,6 +174,27 @@ void tst_QOpenGL::sharedResourceCleanup()
     QCOMPARE(tracker.destructorCalls, 1);
 }
 
+void tst_QOpenGL::multiGroupSharedResourceCleanup()
+{
+    QWindow window;
+    window.setGeometry(0, 0, 10, 10);
+    window.create();
+
+    for (int i = 0; i < 10; ++i) {
+        QOpenGLContext *gl = new QOpenGLContext();
+        gl->create();
+        gl->makeCurrent(&window);
+        {
+            // Cause QOpenGLMultiGroupSharedResource instantiation.
+            QOpenGLFunctions func(gl);
+        }
+        delete gl;
+        // Cause context group's deleteLater() to be processed.
+        QCoreApplication::sendPostedEvents(0, QEvent::DeferredDelete);
+    }
+    // Shouldn't crash when application exits.
+}
+
 static bool fuzzyComparePixels(const QRgb testPixel, const QRgb refPixel, const char* file, int line, int x = -1, int y = -1)
 {
     static int maxFuzz = 1;