git-gui: Work around random missing scrollbar in revision list

If the horizontal scrollbar isn't currently visible (because it has
not been needed) but we get an update to the scroll port we may find
the scrollbar window exists but the Tcl command doesn't.  Apparently
it is possible for Tk to have partially destroyed the scrollbar by
removing the Tcl procedure name but still leaving the widget name in
the window registry.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

diff --git a/lib/choose_rev.tcl b/lib/choose_rev.tcl
index a063c5bc49fc9bad58f7fd78e7446a097ce86b88..c8821c146386f850c0794df70f605cd9f18dcff3 100644 (file)
--- a/lib/choose_rev.tcl
+++ b/lib/choose_rev.tcl
@@ -451,7 +451,8 @@ method _sb_set {sb orient first last} {
                        focus $old_focus
                }
        }
-       $sb set $first $last
+
+       catch {$sb set $first $last}
 }
 
 method _show_tooltip {pos} {