Finalizers must be callable
Non-function __gc metamethods are not ignored; if present, the
metamethod will be called even if it is not a function.
diff --git a/lgc.c b/lgc.c
index c834319..8cb3e9f 100644
--- a/lgc.c
+++ b/lgc.c
@@ -832,7 +832,7 @@
lua_assert(!g->gcemergency);
setgcovalue(L, &v, udata2finalize(g));
tm = luaT_gettmbyobj(L, &v, TM_GC);
- if (ttisfunction(tm)) { /* is the finalizer a function? */
+ if (!notm(tm)) { /* is there a finalizer? */
int status;
lu_byte oldah = L->allowhook;
int running = g->gcrunning;
diff --git a/manual/manual.of b/manual/manual.of
index 63e78f9..1e4ca85 100644
--- a/manual/manual.of
+++ b/manual/manual.of
@@ -689,10 +689,8 @@
Lua goes through that list.
For each object in the list,
it checks the object's @idx{__gc} metamethod:
-If it is a function,
-Lua calls it with the object as its single argument;
-if the metamethod is not a function,
-Lua simply ignores it.
+If it is present,
+Lua calls it with the object as its single argument.
At the end of each garbage-collection cycle,
the finalizers for objects are called in
@@ -726,6 +724,9 @@
Finalizers cannot yield.
+Any error while running a finalizer generates a warning;
+it is not propagated.
+
}
@sect3{weak-table| @title{Weak Tables}
@@ -7279,6 +7280,11 @@
with maximum alignment of 1 (no alignment)
and native endianness.
+Native endianness assumes that the whole system is
+either big or little endian.
+The packing functions will not emulate correctly the behavior
+of mixed-endian formats.
+
Alignment works as follows:
For each option,
the format gets extra padding until the data starts
@@ -7288,6 +7294,7 @@
Options @St{c} and @St{z} are not aligned;
option @St{s} follows the alignment of its starting integer.
+
All padding is filled with zeros by @Lid{string.pack}
(and ignored by @Lid{string.unpack}).
@@ -8720,6 +8727,14 @@
block.
}
+@item{
+When finalizing an object,
+Lua does not ignore @idx{__gc} metamethods that are not functions.
+Any value will be called, if present.
+(Non-callable values will generate a warning,
+like any other error when calling a finalizer.)
+}
+
}
}
