[gtk+] entry: Fix a corner case of overwrite mode

[Matthias Clasen <matthiasc src gnome org>]

commit ddd1ac093436e4c0d5a10b00d30a0f0d39d50bf1
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Oct 5 12:20:14 2016 -0400

    entry: Fix a corner case of overwrite mode
    
    We currently beep when a character is appended at the end in
    overwrite mode. That is obviously not right. Patch based on
    a patch by Ian MacDonald.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=772389

 gtk/gtkentry.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkentry.c b/gtk/gtkentry.c
index 79588a1..312277a 100644
--- a/gtk/gtkentry.c
+++ b/gtk/gtkentry.c
@@ -6021,6 +6021,7 @@ gtk_entry_enter_text (GtkEntry       *entry,
   GtkEditable *editable = GTK_EDITABLE (entry);
   gint tmp_pos;
   gboolean old_need_im_reset;
+  guint text_length;
 
   old_need_im_reset = priv->need_im_reset;
   priv->need_im_reset = FALSE;
@@ -6030,7 +6031,11 @@ gtk_entry_enter_text (GtkEntry       *entry,
   else
     {
       if (priv->overwrite_mode)
-        gtk_entry_delete_from_cursor (entry, GTK_DELETE_CHARS, 1);
+        {
+          text_length = gtk_entry_buffer_get_length (get_buffer (entry));
+          if (priv->current_pos < text_length)
+            gtk_entry_delete_from_cursor (entry, GTK_DELETE_CHARS, 1);
+        }
     }
 
   tmp_pos = priv->current_pos;