nasty GC bug: upvalue must be turned white when not keeping invariant,

but barrier was not being called when uv->v were already white.

lfunc.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lfunc.c,v 2.21 2010/03/26 20:58:11 roberto Exp roberto $
+** $Id: lfunc.c,v 2.22 2010/04/29 17:34:35 roberto Exp roberto $
 ** Auxiliary functions to manipulate prototypes and closures
 ** See Copyright Notice in lua.h
 */
@@ -101,11 +101,7 @@ void luaF_close (lua_State *L, StkId level) {
       uv->v = &uv->u.value;  /* now current value lives here */
       gch(o)->next = g->allgc;  /* link upvalue into 'allgc' list */
       g->allgc = o;
-      lua_assert(!isblack(o));  /* open upvalues are never black */
-      if (isgray(o)) {  /* is it marked? */
-        gray2black(o);  /* could not be black; now it can */
-        luaC_barrier(L, uv, uv->v);
-      }
+      luaC_checkupvalcolor(g, uv);
     }
   }
 }

lgc.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lgc.c,v 2.80 2010/04/26 17:58:00 roberto Exp roberto $
+** $Id: lgc.c,v 2.81 2010/04/29 17:32:40 roberto Exp roberto $
 ** Garbage Collector
 ** See Copyright Notice in lua.h
 */
@@ -146,6 +146,26 @@ void luaC_barrierback (lua_State *L, Table *t) {
 }
 
 
+/*
+** check color (and invariants) for an upvalue that was closed,
+** i.e., moved into the 'allgc' list
+*/
+void luaC_checkupvalcolor (global_State *g, UpVal *uv) {
+  GCObject *o = obj2gco(uv);
+  lua_assert(!isblack(o));  /* open upvalues are never black */
+  if (isgray(o)) {
+    if (keepinvariant(g)) {
+      gray2black(o);  /* it is being visited now */
+      markvalue(g, uv->v);
+    }
+    else {
+      lua_assert(issweepphase(g));
+      makewhite(g, o);
+    }
+  }
+}
+
+
 /*
 ** create a new collectable object (with given type and size) and link
 ** it to '*list'. 'offset' tells how many bytes to allocate before the

lgc.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lgc.h,v 2.30 2010/03/25 13:06:36 roberto Exp roberto $
+** $Id: lgc.h,v 2.31 2010/04/29 17:32:40 roberto Exp roberto $
 ** Garbage Collector
 ** See Copyright Notice in lua.h
 */
@@ -9,6 +9,7 @@
 
 
 #include "lobject.h"
+#include "lstate.h"
 
 
 /*
@@ -120,6 +121,6 @@ LUAI_FUNC GCObject *luaC_newobj (lua_State *L, int tt, size_t sz,
 LUAI_FUNC void luaC_barrierf (lua_State *L, GCObject *o, GCObject *v);
 LUAI_FUNC void luaC_barrierback (lua_State *L, Table *t);
 LUAI_FUNC void luaC_checkfinalizer (lua_State *L, Udata *u);
-
+LUAI_FUNC void luaC_checkupvalcolor (global_State *g, UpVal *uv);
 
 #endif