[gspell] InlineCheckerTextBuffer: replace asserts by more useful warnings

[Sébastien Wilmet <swilmet src gnome org>]

commit bc52e8383c47c2f295e91ef7f4d77cd9e4b98a6c
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sun Apr 2 17:12:58 2017 +0200

    InlineCheckerTextBuffer: replace asserts by more useful warnings
    
    If the bug happens, it doesn't depend on gspell code, it depends on
    lower-level libraries (GTK+, Pango). By printing warnings we avoid the
    crash, and more useful info is printed.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=778883

 gspell/gspell-inline-checker-text-buffer.c |   29 ++++++++++++++++++++++++---
 1 files changed, 25 insertions(+), 4 deletions(-)
---
diff --git a/gspell/gspell-inline-checker-text-buffer.c b/gspell/gspell-inline-checker-text-buffer.c
index b7c2268..3c6b400 100644
--- a/gspell/gspell-inline-checker-text-buffer.c
+++ b/gspell/gspell-inline-checker-text-buffer.c
@@ -467,6 +467,7 @@ check_visible_region_in_view (GspellInlineCheckerTextBuffer *spell,
                GtkTextIter end;
                GtkTextIter orig_start;
                GtkTextIter orig_end;
+               gboolean bug = FALSE;
 
                if (!_gspell_region_iter_get_subregion (&intersect_iter, &start, &end))
                {
@@ -497,11 +498,31 @@ check_visible_region_in_view (GspellInlineCheckerTextBuffer *spell,
                }
 
                /* Ensure that we don't have an infinite loop. We must subtract
-                * from scan_region at least [start, end], otherwise we will
-                * re-check the same subregion again and again.
+                * from scan_region at least [orig_start, orig_end], otherwise
+                * we will re-check the same subregion again and again.
                 */
-               g_assert (gtk_text_iter_compare (&start, &orig_start) <= 0);
-               g_assert (gtk_text_iter_compare (&orig_end, &end) <= 0);
+               if (gtk_text_iter_compare (&orig_start, &start) < 0)
+               {
+                       g_warning ("Should not reach this code path.");
+                       bug = TRUE;
+                       start = orig_start;
+               }
+               if (gtk_text_iter_compare (&end, &orig_end) < 0)
+               {
+                       g_warning ("Should not reach this code path.");
+                       bug = TRUE;
+                       end = orig_end;
+               }
+
+               if (bug)
+               {
+                       gchar *text;
+
+                       text = gtk_text_iter_get_slice (&start, &end);
+                       g_warning ("Text that caused the bug: '%s'", text);
+                       g_warning ("Please report the bug to: " PACKAGE_BUGREPORT);
+                       g_free (text);
+               }
 
                _gspell_region_subtract_subregion (spell->scan_region, &start, &end);