[gtk] textbuffer: Be careful with tags when copying

[Matthias Clasen <matthiasc src gnome org>]

commit 0add6268224e705f6e3f8f26289846e046098a81
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Aug 2 13:54:06 2020 -0400

    textbuffer: Be careful with tags when copying
    
    We can only insert tags in the buffer if they come
    from the same GtkTextTagTable as the buffer uses.
    If that is not the case, paste the text without tags.
    
    Fixes: #2991

 gtk/gtktextbuffer.c | 39 +++++++++++++++++++--------------------
 1 file changed, 19 insertions(+), 20 deletions(-)
---
diff --git a/gtk/gtktextbuffer.c b/gtk/gtktextbuffer.c
index 3e7e12c0fa..1f616bdce1 100644
--- a/gtk/gtktextbuffer.c
+++ b/gtk/gtktextbuffer.c
@@ -1605,15 +1605,15 @@ insert_range_not_inside_self (GtkTextBuffer     *buffer,
   GtkTextIter end = *orig_end;
   GtkTextIter range_start;
   GtkTextIter range_end;
-  
+
   if (gtk_text_iter_equal (orig_start, orig_end))
     return;
-  
+
   gtk_text_iter_order (&start, &end);
 
   range_start = start;
-  range_end = start;  
-  
+  range_end = start;
+
   while (TRUE)
     {
       int start_offset;
@@ -1621,12 +1621,12 @@ insert_range_not_inside_self (GtkTextBuffer     *buffer,
       GSList *tags;
       GSList *tmp_list;
       Range *r;
-      
+
       if (gtk_text_iter_equal (&range_start, &end))
         break; /* All done */
 
       g_assert (gtk_text_iter_compare (&range_start, &end) < 0);
-      
+
       gtk_text_iter_forward_to_tag_toggle (&range_end, NULL);
 
       g_assert (!gtk_text_iter_equal (&range_start, &range_end));
@@ -1634,33 +1634,32 @@ insert_range_not_inside_self (GtkTextBuffer     *buffer,
       /* Clamp to the end iterator */
       if (gtk_text_iter_compare (&range_end, &end) > 0)
         range_end = end;
-      
+
       /* We have a range with unique tags; insert it, and
        * apply all tags.
        */
       start_offset = gtk_text_iter_get_offset (iter);
 
       r = save_range (&range_start, &range_end, &end);
-      
+
       insert_range_untagged (buffer, iter, &range_start, &range_end, interactive);
 
       restore_range (r);
       r = NULL;
-      
-      gtk_text_buffer_get_iter_at_offset (buffer, &start_iter, start_offset);
-      
-      tags = gtk_text_iter_get_tags (&range_start);
-      tmp_list = tags;
-      while (tmp_list != NULL)
+
+      if (gtk_text_buffer_get_tag_table (gtk_text_iter_get_buffer (orig_start)) == 
gtk_text_buffer_get_tag_table (buffer))
         {
-          gtk_text_buffer_apply_tag (buffer,
-                                     tmp_list->data,
-                                     &start_iter,
-                                     iter);
+          gtk_text_buffer_get_iter_at_offset (buffer, &start_iter, start_offset);
 
-          tmp_list = tmp_list->next;
+          tags = gtk_text_iter_get_tags (&range_start);
+          tmp_list = tags;
+          while (tmp_list != NULL)
+            {
+              gtk_text_buffer_apply_tag (buffer, tmp_list->data, &start_iter, iter);
+              tmp_list = tmp_list->next;
+            }
+          g_slist_free (tags);
         }
-      g_slist_free (tags);
 
       range_start = range_end;
     }