'index2value' more robust
'index2value' accepts pseudo-indices also when called from a Lua
function, through a hook.
diff --git a/lapi.c b/lapi.c
index f8f70cd..3467891 100644
--- a/lapi.c
+++ b/lapi.c
@@ -53,6 +53,10 @@
#define isupvalue(i) ((i) < LUA_REGISTRYINDEX)
+/*
+** Convert an acceptable index to a pointer to its respective value.
+** Non-valid indices return the special nil value 'G(L)->nilvalue'.
+*/
static TValue *index2value (lua_State *L, int idx) {
CallInfo *ci = L->ci;
if (idx > 0) {
@@ -70,22 +74,26 @@
else { /* upvalues */
idx = LUA_REGISTRYINDEX - idx;
api_check(L, idx <= MAXUPVAL + 1, "upvalue index too large");
- if (ttislcf(s2v(ci->func))) /* light C function? */
- return &G(L)->nilvalue; /* it has no upvalues */
- else {
+ if (ttisCclosure(s2v(ci->func))) { /* C closure? */
CClosure *func = clCvalue(s2v(ci->func));
return (idx <= func->nupvalues) ? &func->upvalue[idx-1]
: &G(L)->nilvalue;
}
+ else { /* light C function or Lua function (through a hook)?) */
+ api_check(L, ttislcf(s2v(ci->func)), "caller not a C function");
+ return &G(L)->nilvalue; /* no upvalues */
+ }
}
}
-
+/*
+** Convert a valid actual index (not a pseudo-index) to its address.
+*/
static StkId index2stack (lua_State *L, int idx) {
CallInfo *ci = L->ci;
if (idx > 0) {
StkId o = ci->func + idx;
- api_check(L, o < L->top, "unacceptable index");
+ api_check(L, o < L->top, "invalid index");
return o;
}
else { /* non-positive index */
