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Upvalues removed from 'openupval' before being closed

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Undo commit c220b0a5d0: '__close' is not called again in case of
errors. (Upvalue is removed from the list before the call.) The
common error that justified that change was C stack overflows, which
are much rarer with the stackless implementation.
This commit is contained in:
Roberto Ierusalimschy
2020-12-21 15:21:45 -03:00
parent 409256b784
commit f9d29b0c44
3 changed files with 31 additions and 26 deletions
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30
lfunc.c
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@@ -220,24 +220,38 @@ void luaF_unlinkupval (UpVal *uv) {
}
/*
** Close all upvalues up to the given stack level. 'status' indicates
** how/why the function was called:
** - LUA_OK: regular code exiting the scope of a variable; may raise
** an error due to errors in __close metamethods;
** - CLOSEPROTECT: finishing a thread; run all metamethods in protected
** mode;
** - NOCLOSINGMETH: close upvalues without running __close metamethods;
** - other values: error status from previous errors, to be propagated.
**
** Returns the resulting status, either the original status or an error
** in a closing method.
*/
int luaF_close (lua_State *L, StkId level, int status) {
UpVal *uv;
while ((uv = L->openupval) != NULL && uplevel(uv) >= level) {
StkId upl; /* stack index pointed by 'uv' */
while ((uv = L->openupval) != NULL && (upl = uplevel(uv)) >= level) {
TValue *slot = &uv->u.value; /* new position for value */
lua_assert(uplevel(uv) < L->top);
if (uv->tbc && status != NOCLOSINGMETH) {
/* must run closing method, which may change the stack */
ptrdiff_t levelrel = savestack(L, level);
status = callclosemth(L, uplevel(uv), status);
level = restorestack(L, levelrel);
}
luaF_unlinkupval(uv);
luaF_unlinkupval(uv); /* remove upvalue from 'openupval' list */
setobj(L, slot, uv->v); /* move value to upvalue slot */
uv->v = slot; /* now current value lives here */
if (!iswhite(uv)) { /* neither white nor dead? */
nw2black(uv); /* closed upvalues cannot be gray */
luaC_barrier(L, uv, slot);
}
if (uv->tbc && status != NOCLOSINGMETH) {
/* must run closing method, which may change the stack */
ptrdiff_t levelrel = savestack(L, level);
status = callclosemth(L, upl, status);
level = restorestack(L, levelrel);
}
}
return status;
}