[gnome-latex] Document: add hack to avoid crash on app shutdown

[Sébastien Wilmet <swilmet src gnome org>]

commit cfc9a5a7dea998bf7182c676b4d8bb16d2ec4410
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Thu May 31 18:17:20 2018 +0200

    Document: add hack to avoid crash on app shutdown
    
    With valac <= 0.40 the Document objects were anyway also leaked, see:
    https://gitlab.gnome.org/GNOME/gnome-latex/issues/35
    
    Maybe the easiest solution is to rewrite everything in C.
    
    Fixes https://gitlab.gnome.org/GNOME/gnome-latex/issues/57

 src/document.vala | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/src/document.vala b/src/document.vala
index 47a962a..c4ef85f 100644
--- a/src/document.vala
+++ b/src/document.vala
@@ -34,6 +34,11 @@ public class Document : Tepl.Buffer
 
     public Document ()
     {
+        // FIXME properly: horrible hack, keep the Document objects alive, to
+        // avoid a crash on application shutdown:
+        // https://gitlab.gnome.org/GNOME/gnome-latex/issues/57
+        this.ref ();
+
         // syntax highlighting: LaTeX by default
         var lm = Gtk.SourceLanguageManager.get_default ();
         set_language (lm.get_language ("latex"));