[gjs/gnome-3-24] closure: Prevent collection of invalidated closure

[Philip Chimento <pchimento src gnome org>]

commit 3e00e7adcba12c6b702ed77aba2721194843912e
Author: Philip Chimento <philip chimento gmail com>
Date:   Tue Aug 22 22:58:56 2017 -0700

    closure: Prevent collection of invalidated closure
    
    It's not possible to stop tracing an object in the middle of GC. However,
    by using JS::ExposeObjectToActiveJS(), it is possible to mark an object
    as reachable for the duration of one GC. This is exactly what we need for
    closures, to keep the closure's callable object from disappearing while
    GC is going on.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=786668
    
    https://bugzilla.gnome.org/show_bug.cgi?id=785657

 gi/closure.cpp |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/gi/closure.cpp b/gi/closure.cpp
index 54971aa..9cbc60f 100644
--- a/gi/closure.cpp
+++ b/gi/closure.cpp
@@ -166,6 +166,7 @@ closure_set_invalid(gpointer  data,
 {
     Closure *self = &((GjsClosure*) closure)->priv;
 
+    JS::ExposeObjectToActiveJS(self->obj);
     self->obj.reset();
     self->context = nullptr;