Fix bidi_cache_find when NEUTRALS_OK is false; RLI no longer aborts.

1 files changed, 13 insertions, 8 deletions

diff --git a/src/bidi.c b/src/bidi.c
index 2e980e92b27..6d5f281d571 100644
--- a/src/bidi.c
+++ b/src/bidi.c
@@ -358,6 +358,12 @@ bidi_get_category (bidi_type_t type)
     }
 }
 
+static bool
+bidi_isolate_fmt_char (bidi_type_t ch_type)
+{
+  return (ch_type == LRI || ch_type == RLI || ch_type == PDI || ch_type == FSI);
+}
+
 /* Return the mirrored character of C, if it has one.  If C has no
    mirrored counterpart, return C.
    Note: The conditions in UAX#9 clause L4 regarding the surrounding
@@ -804,8 +810,13 @@ bidi_cache_find (ptrdiff_t charpos, bool neutrals_ok, struct bidi_it *bidi_it)
 
   if (i >= bidi_cache_start
       && (neutrals_ok
+          /* Callers that don't want to resolve neutrals (and set
+             neutrals_ok = false) need to be sure that there's enough
+             info in the cached state to resolve the neutrals and
+             isolates, and if not, they don't want the cached state.  */
           || !(bidi_cache[i].resolved_level == -1
-               && bidi_get_category (bidi_cache[i].type) == NEUTRAL
+               && (bidi_get_category (bidi_cache[i].type) == NEUTRAL
+                   || bidi_isolate_fmt_char (bidi_cache[i].type))
                && bidi_cache[i].next_for_neutral.type == UNKNOWN_BT)))
     {
       bidi_dir_t current_scan_dir = bidi_it->scan_dir;
@@ -2037,12 +2048,6 @@ bidi_resolve_explicit (struct bidi_it *bidi_it)
   return bidi_it->resolved_level;
 }
 
-static bool
-bidi_isolate_fmt_char (bidi_type_t ch_type)
-{
-  return (ch_type == LRI || ch_type == RLI || ch_type == PDI || ch_type == FSI);
-}
-
 /* Advance in the buffer/string, resolve weak types and return the
    type of the next character after weak type resolution.  */
 static bidi_type_t
@@ -2837,7 +2842,7 @@ bidi_level_of_next_char (struct bidi_it *bidi_it)
               eassert (bidi_it->resolved_level >= 0);
               return bidi_it->resolved_level;
             }
-          else if (next_char_pos >= bob - 1)
+          else
             {
               level = bidi_it->level_stack[bidi_it->stack_idx].level;
               if (bidi_get_category (type) == NEUTRAL