Re: Problem with markers in sourceview

From: Mike Spivey <[email protected]>
> This test program allows markers to be set on lines in a GSourceView
> widget by clicking in the left margin.  On my setup (OCaml 3.10.2-3,
> Lablgtk 2.10.1-2, Ubuntu Intrepid), GTK shows critical errors after I
> click a couple of times.
> 
> (bug:12461): GLib-GObject-CRITICAL **: g_object_unref: assertion
> `G_IS_OBJECT (object)' failed
> 
> I've deliberately made the program turn over lots of memory; without the
> added code, it takes thirty clicks or so before the same message appears.
> 
> What am I doing wrong?
> 
> -- Mike

Nothing wrong on you side. This looks like a bug in LablGtkSourceView
(which was recently merged into lablgtk2), which assumed that a newly
created marker was owned by the user, whereas the documentation says
that it is owned by the buffer.
Here is a patch that fixes the problem (just removes the _new suffix)

Index: src/ml_gtksourceview.c
===================================================================
--- src/ml_gtksourceview.c	(revision 1429)
+++ src/ml_gtksourceview.c	(working copy)
@@ -361,7 +361,7 @@
 ML_1 (gtk_source_buffer_begin_not_undoable_action, GtkSourceBuffer_val, Unit)
 ML_1 (gtk_source_buffer_end_not_undoable_action, GtkSourceBuffer_val, Unit)
 ML_4 (gtk_source_buffer_create_marker, GtkSourceBuffer_val,
-      String_option_val, String_option_val, GtkTextIter_val, Val_GtkSourceMarker_new)
+      String_option_val, String_option_val, GtkTextIter_val, Val_GtkSourceMarker)
 ML_3 (gtk_source_buffer_move_marker, GtkSourceBuffer_val,
       GtkSourceMarker_val, GtkTextIter_val, Unit)
 ML_2 (gtk_source_buffer_delete_marker, GtkSourceBuffer_val,


[Your code]
> 
> let _ = GMain.init ()
> 
> let gensym = ref 0
> 
> let source_click (view : GSourceView.source_view) ev =
>   if GdkEvent.get_type ev = `BUTTON_PRESS
>       && view#get_window_type (GdkEvent.get_window ev) = `LEFT then begin
>     let (x, y) =
>       view#window_to_buffer_coords `LEFT
> 	(truncate (GdkEvent.Button.x ev))
> 	(truncate (GdkEvent.Button.y ev)) in
>     let (iter, _) = view#get_line_at_y y in
>     let buf = view#source_buffer in
>     let marks =
>       List.filter (fun mk -> mk#get_type = "breakpoint")
> 	(buf#get_markers_in_region iter iter) in
>     if marks <> [] then
>       buf#delete_marker (List.hd marks)
>     else begin
>       incr gensym;
>       ignore (buf#create_marker ~name:(string_of_int !gensym)
> 	~typ:"breakpoint" iter);
>     end
>   end;
> 
>   (* Create lots of garbage *)
>   let rec loop n xs = if n = 0 then () else loop (n-1) (n::xs) in
>   loop 1000000 [];
> 
>   (* Swallow the event *)
>   true
> 
> let main () =
>   let win = GWindow.window ~width:100 ~height:100 () in
>   let buf = GSourceView.source_buffer ~text:"1\n2\n3\n" () in
>   let view =
>     GSourceView.source_view ~source_buffer:buf
>       ~show_line_markers:true
>       ~packing:win#add () in
>   view#set_marker_pixbuf "breakpoint"
>     (GdkPixbuf.from_file "/usr/share/pixmaps/apple-red.png");
>   ignore (view#event#connect#button_press (source_click view));
>   win#show ();
>   GMain.main ()
> 
> let _ = main ()
> 
> 
> 
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