Improve debug output with really deep nesting

src/hb-private.hh

@@ -689,17 +689,20 @@ _hb_debug_msg_va (const char *what,
     fprintf (stderr, " %*s  ", (unsigned int) (2 * sizeof (void *)), "");
 
   if (indented) {
-/* One may want to add ASCII version of these.  See:
- * https://bugs.freedesktop.org/show_bug.cgi?id=50970 */
 #define VBAR	"\342\224\202"	/* U+2502 BOX DRAWINGS LIGHT VERTICAL */
 #define VRBAR	"\342\224\234"	/* U+251C BOX DRAWINGS LIGHT VERTICAL AND RIGHT */
 #define DLBAR	"\342\225\256"	/* U+256E BOX DRAWINGS LIGHT ARC DOWN AND LEFT */
 #define ULBAR	"\342\225\257"	/* U+256F BOX DRAWINGS LIGHT ARC UP AND LEFT */
 #define LBAR	"\342\225\264"	/* U+2574 BOX DRAWINGS LIGHT LEFT */
-    static const char bars[] = VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR;
+    static const char bars[] =
+      VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR
+      VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR
+      VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR
+      VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR
+      VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR VBAR;
     fprintf (stderr, "%2u %s" VRBAR "%s",
 	     level,
-	     bars + sizeof (bars) - 1 - MIN ((unsigned int) sizeof (bars), (unsigned int) (sizeof (VBAR) - 1) * level),
+	     bars + sizeof (bars) - 1 - MIN ((unsigned int) sizeof (bars) - 1, (unsigned int) (sizeof (VBAR) - 1) * level),
 	     level_dir ? (level_dir > 0 ? DLBAR : ULBAR) : LBAR);
   } else
     fprintf (stderr, "   " VRBAR LBAR);