1 files changed, 30 insertions, 16 deletions

diff --git a/libs/liblua/src/ltable.c b/libs/liblua/src/ltable.c
index 5a0d066faa..7e7cbed97c 100644
--- a/libs/liblua/src/ltable.c
+++ b/libs/liblua/src/ltable.c
@@ -166,17 +166,30 @@ static Node *mainpositionTV (const Table *t, const TValue *key) {
 
 
 /*
-** Check whether key 'k1' is equal to the key in node 'n2'.
-** This equality is raw, so there are no metamethods. Floats
-** with integer values have been normalized, so integers cannot
-** be equal to floats. It is assumed that 'eqshrstr' is simply
-** pointer equality, so that short strings are handled in the
-** default case.
-*/
-static int equalkey (const TValue *k1, const Node *n2) {
-  if (rawtt(k1) != keytt(n2))  /* not the same variants? */
+** Check whether key 'k1' is equal to the key in node 'n2'. This
+** equality is raw, so there are no metamethods. Floats with integer
+** values have been normalized, so integers cannot be equal to
+** floats. It is assumed that 'eqshrstr' is simply pointer equality, so
+** that short strings are handled in the default case.
+** A true 'deadok' means to accept dead keys as equal to their original
+** values. All dead keys are compared in the default case, by pointer
+** identity. (Only collectable objects can produce dead keys.) Note that
+** dead long strings are also compared by identity.
+** Once a key is dead, its corresponding value may be collected, and
+** then another value can be created with the same address. If this
+** other value is given to 'next', 'equalkey' will signal a false
+** positive. In a regular traversal, this situation should never happen,
+** as all keys given to 'next' came from the table itself, and therefore
+** could not have been collected. Outside a regular traversal, we
+** have garbage in, garbage out. What is relevant is that this false
+** positive does not break anything.  (In particular, 'next' will return
+** some other valid item on the table or nil.)
+*/
+static int equalkey (const TValue *k1, const Node *n2, int deadok) {
+  if ((rawtt(k1) != keytt(n2)) &&  /* not the same variants? */
+       !(deadok && keyisdead(n2) && iscollectable(k1)))
    return 0;  /* cannot be same key */
-  switch (ttypetag(k1)) {
+  switch (keytt(n2)) {
     case LUA_VNIL: case LUA_VFALSE: case LUA_VTRUE:
       return 1;
     case LUA_VNUMINT:
@@ -187,7 +200,7 @@ static int equalkey (const TValue *k1, const Node *n2) {
       return pvalue(k1) == pvalueraw(keyval(n2));
     case LUA_VLCF:
       return fvalue(k1) == fvalueraw(keyval(n2));
-    case LUA_VLNGSTR:
+    case ctb(LUA_VLNGSTR):
       return luaS_eqlngstr(tsvalue(k1), keystrval(n2));
     default:
       return gcvalue(k1) == gcvalueraw(keyval(n2));
@@ -251,11 +264,12 @@ static unsigned int setlimittosize (Table *t) {
 /*
 ** "Generic" get version. (Not that generic: not valid for integers,
 ** which may be in array part, nor for floats with integral values.)
+** See explanation about 'deadok' in function 'equalkey'.
 */
-static const TValue *getgeneric (Table *t, const TValue *key) {
+static const TValue *getgeneric (Table *t, const TValue *key, int deadok) {
   Node *n = mainpositionTV(t, key);
   for (;;) {  /* check whether 'key' is somewhere in the chain */
-    if (equalkey(key, n))
+    if (equalkey(key, n, deadok))
       return gval(n);  /* that's it */
     else {
       int nx = gnext(n);
@@ -292,7 +306,7 @@ static unsigned int findindex (lua_State *L, Table *t, TValue *key,
   if (i - 1u < asize)  /* is 'key' inside array part? */
     return i;  /* yes; that's the index */
   else {
-    const TValue *n = getgeneric(t, key);
+    const TValue *n = getgeneric(t, key, 1);
     if (unlikely(isabstkey(n)))
       luaG_runerror(L, "invalid key to 'next'");  /* key not found */
     i = cast_int(nodefromval(n) - gnode(t, 0));  /* key index in hash table */
@@ -730,7 +744,7 @@ const TValue *luaH_getstr (Table *t, TString *key) {
   else {  /* for long strings, use generic case */
     TValue ko;
     setsvalue(cast(lua_State *, NULL), &ko, key);
-    return getgeneric(t, &ko);
+    return getgeneric(t, &ko, 0);
   }
 }
 
@@ -750,7 +764,7 @@ const TValue *luaH_get (Table *t, const TValue *key) {
       /* else... */
     }  /* FALLTHROUGH */
     default:
-      return getgeneric(t, key);
+      return getgeneric(t, key, 0);
   }
 }