Upvalues removed from 'openupval' before being closed
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.
diff --git a/lfunc.c b/lfunc.c
index c4360f0..6608592 100644
--- a/lfunc.c
+++ b/lfunc.c
@@ -220,24 +220,38 @@
}
+/*
+** 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;
}
diff --git a/manual/manual.of b/manual/manual.of
index 164e359..5d0c35c 100644
--- a/manual/manual.of
+++ b/manual/manual.of
@@ -1630,7 +1630,6 @@
If there is any error while running a closing method,
that error is handled like an error in the regular code
where the variable was defined.
-However, Lua may call the method one more time.
After an error,
the other pending closing methods will still be called.
diff --git a/testes/locals.lua b/testes/locals.lua
index e2f6f35..d32a9a3 100644
--- a/testes/locals.lua
+++ b/testes/locals.lua
@@ -392,21 +392,13 @@
local y <close> =
func2close(function (self, msg)
- assert(string.find(msg, "@z")) -- first error in 'z'
- checkwarn("@z") -- second error in 'z' generated a warning
+ assert(string.find(msg, "@z")) -- error in 'z'
error("@y")
end)
- local first = true
local z <close> =
- -- 'z' close is called twice
func2close(function (self, msg)
- if first then
- assert(msg == nil)
- first = false
- else
- assert(string.find(msg, "@z")) -- own error
- end
+ assert(msg == nil)
error("@z")
end)
@@ -468,8 +460,8 @@
local function foo (...)
do
local x1 <close> =
- func2close(function ()
- checkwarn("@X")
+ func2close(function (self, msg)
+ assert(string.find(msg, "@X"))
error("@Y")
end)
@@ -494,8 +486,6 @@
local st, msg = xpcall(foo, debug.traceback)
assert(string.match(msg, "^[^ ]* @x123"))
assert(string.find(msg, "in metamethod 'close'"))
- checkwarn("@x123") -- from second call to close 'x123'
-
endwarn()
end
@@ -686,8 +676,10 @@
local x = 0
local y = 0
co = coroutine.wrap(function ()
- local xx <close> = func2close(function ()
- y = y + 1; checkwarn("XXX"); error("YYY")
+ local xx <close> = func2close(function (_, err)
+ y = y + 1;
+ assert(string.find(err, "XXX"))
+ error("YYY")
end)
local xv <close> = func2close(function ()
x = x + 1; error("XXX")
@@ -697,7 +689,7 @@
end)
assert(co() == 100); assert(x == 0)
local st, msg = pcall(co)
- assert(x == 2 and y == 1) -- first close is called twice
+ assert(x == 1 and y == 1)
-- should get first error raised
assert(not st and string.find(msg, "%w+%.%w+:%d+: XXX"))
checkwarn("YYY")
