1 files changed, 16 insertions, 34 deletions

diff --git a/src/composite.c b/src/composite.c
index 392da1ceba1..233f9ac8969 100644
--- a/src/composite.c
+++ b/src/composite.c
@@ -969,7 +969,9 @@ autocmp_chars (Lisp_Object rule, EMACS_INT charpos, EMACS_INT bytepos, EMACS_INT
 static Lisp_Object _work_val;
 static int _work_char;
 
-/* 1 iff the character C is composable.  */
+/* 1 iff the character C is composable.  Characters of general
+   category Z? or C? are not composable except for ZWNJ and ZWJ. */
+
 #define CHAR_COMPOSABLE_P(C)                                            \
   ((C) == 0x200C || (C) == 0x200D                                       \
    || (_work_val = CHAR_TABLE_REF (Vunicode_category_table, (C)),       \
@@ -1028,19 +1030,6 @@ composition_compute_stop_pos (struct composition_it *cmp_it, EMACS_INT charpos,
       cmp_it->stop_pos = endpos = start;
       cmp_it->ch = -1;
     }
-  if (NILP (string))
-    {
-      /* A composition never strides over PT.  */
-      if (PT > charpos)
-        {
-          if (PT < endpos)
-            cmp_it->stop_pos = endpos = PT;
-        }
-      else if (PT < charpos && PT > endpos)
-        {
-          cmp_it->stop_pos = endpos = PT - 1;
-        }
-    }
   if (NILP (current_buffer->enable_multibyte_characters)
       || NILP (Vauto_composition_mode))
     return;
@@ -1091,6 +1080,16 @@ composition_compute_stop_pos (struct composition_it *cmp_it, EMACS_INT charpos,
                 }
             }
         }
+      if (charpos == endpos)
+        {
+          /* We couldn't find a composition point before ENDPOS.  But,
+             some character after ENDPOS may be composed with
+             characters before ENDPOS.  So, we should stop at the safe
+             point.  */
+          charpos = endpos - MAX_AUTO_COMPOSITION_LOOKBACK;
+          if (charpos < start)
+            charpos = start;
+        }
     }
   else if (charpos > endpos)
     {
@@ -1223,23 +1222,8 @@ composition_compute_stop_pos (struct composition_it *cmp_it, EMACS_INT charpos,
 int
 composition_reseat_it (struct composition_it *cmp_it, EMACS_INT charpos, EMACS_INT bytepos, EMACS_INT endpos, struct window *w, struct face *face, Lisp_Object string)
 {
-  if (endpos <= charpos)
-    {
-      if (NILP (string))
-        {
-          if (endpos < 0)
-            endpos = BEGV;
-          if (endpos < PT && PT < charpos)
-            endpos = PT;
-        }
-      else if (endpos < 0)
-        endpos = 0;
-    }
-  else
-    {
-      if (NILP (string) && charpos < PT && PT < endpos)
-        endpos = PT;
-    }
+  if (endpos < 0)
+    endpos = NILP (string) ? BEGV : 0;
 
   if (cmp_it->ch == -2)
     {
@@ -1301,7 +1285,7 @@ composition_reseat_it (struct composition_it *cmp_it, EMACS_INT charpos, EMACS_I
               elt = XCAR (val);
               if (cmp_it->lookback > 0)
                 {
-                  cpos -= cmp_it->lookback;
+                  cpos = charpos - cmp_it->lookback;
                   if (STRINGP (string))
                     bpos = string_char_to_byte (string, cpos);
                   else
@@ -1763,8 +1747,6 @@ should be ignored.  */)
 
   CHECK_NATNUM (from);
   CHECK_NATNUM (to);
-  if (XINT (to) > XINT (from) + MAX_COMPOSITION_COMPONENTS)
-    to = make_number (XINT (from) + MAX_COMPOSITION_COMPONENTS);
   if (! FONT_OBJECT_P (font_object))
     {
       struct coding_system *coding;