bug: __newindex metamethod may not work if metatable is its own

metatable + luaV_settable does not create entry when there is a
metamethod (and therefore entry is useless)

1 files changed, 17 insertions, 12 deletions

diff --git a/ltable.c b/ltable.c
index b2f40083..1bfe616c 100644
--- a/ltable.c
+++ b/ltable.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ltable.c,v 2.60 2011/06/16 14:14:31 roberto Exp roberto $
+** $Id: ltable.c,v 2.61 2011/08/09 20:58:29 roberto Exp roberto $
 ** Lua tables (hash)
 ** See Copyright Notice in lua.h
 */
@@ -322,8 +322,11 @@ void luaH_resize (lua_State *L, Table *t, int nasize, int nhsize) {
   /* re-insert elements from hash part */
   for (i = twoto(oldhsize) - 1; i >= 0; i--) {
     Node *old = nold+i;
-    if (!ttisnil(gval(old)))
+    if (!ttisnil(gval(old))) {
+      /* doesn't need barrier/invalidate cache, as entry was
+         already present in the table */
       setobjt2t(L, luaH_set(L, t, gkey(old)), gval(old));
+    }
   }
   if (!isdummy(nold))
     luaM_freearray(L, nold, twoto(oldhsize));  /* free old array */
@@ -398,14 +401,18 @@ static Node *getfreepos (Table *t) {
 ** put new key in its main position; otherwise (colliding node is in its main
 ** position), new key goes to an empty position.
 */
-static TValue *newkey (lua_State *L, Table *t, const TValue *key) {
+TValue *luaH_newkey (lua_State *L, Table *t, const TValue *key) {
   Node *mp = mainposition(t, key);
+  if (ttisnil(key)) luaG_runerror(L, "table index is nil");
+  else if (ttisnumber(key) && luai_numisnan(L, nvalue(key)))
+    luaG_runerror(L, "table index is NaN");
   if (!ttisnil(gval(mp)) || isdummy(mp)) {  /* main position is taken? */
     Node *othern;
     Node *n = getfreepos(t);  /* get a free place */
     if (n == NULL) {  /* cannot find a free place? */
       rehash(L, t, key);  /* grow table */
-      return luaH_set(L, t, key);  /* re-insert key into grown table */
+      /* whatever called 'newkey' take care of TM cache and GC barrier */
+      return luaH_set(L, t, key);  /* insert key into grown table */
     }
     lua_assert(!isdummy(n));
     othern = mainposition(t, gkey(mp));
@@ -493,17 +500,15 @@ const TValue *luaH_get (Table *t, const TValue *key) {
 }
 
 
+/*
+** beware: when using this function you probably need to check a GC
+** barrier and invalidate the TM cache.
+*/
 TValue *luaH_set (lua_State *L, Table *t, const TValue *key) {
   const TValue *p = luaH_get(t, key);
-  t->flags = 0;
   if (p != luaO_nilobject)
     return cast(TValue *, p);
-  else {
-    if (ttisnil(key)) luaG_runerror(L, "table index is nil");
-    else if (ttisnumber(key) && luai_numisnan(L, nvalue(key)))
-      luaG_runerror(L, "table index is NaN");
-    return newkey(L, t, key);
-  }
+  else return luaH_newkey(L, t, key);
 }
 
 
@@ -515,7 +520,7 @@ void luaH_setint (lua_State *L, Table *t, int key, TValue *value) {
   else {
     TValue k;
     setnvalue(&k, cast_num(key));
-    cell = newkey(L, t, &k);
+    cell = luaH_newkey(L, t, &k);
   }
   setobj2t(L, cell, value);
 }