[gnome-shell] st-label: Unset clutter text instance on disposal

[Florian Müllner <fmuellner src gnome org>]

commit 44894262f49b9f8b2809321ebcf1cd9426303fd6
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Tue May 29 02:28:26 2018 +0300

    st-label: Unset clutter text instance on disposal
    
    The instance is owned by the actor (being its child), and thus when the
    disposal happens for the parent the text is disposed too, thus it's just
    safer to nullify its reference so that we won't try to access to invalid
    objects later, and this might be the case since the JS objects could be kept
    around until they aren't finalized.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=788931

 src/st/st-label.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/st/st-label.c b/src/st/st-label.c
index a7893b074..515e34323 100644
--- a/src/st/st-label.c
+++ b/src/st/st-label.c
@@ -180,6 +180,7 @@ st_label_dispose (GObject   *object)
 {
   StLabelPrivate *priv = ST_LABEL (object)->priv;
 
+  priv->label = NULL;
   g_clear_pointer (&priv->text_shadow_pipeline, cogl_object_unref);
 
   G_OBJECT_CLASS (st_label_parent_class)->dispose (object);