I dug into this question b/c I noticed that in plugin.thrift, the
t_const_value seemed to not be behaving as a union should. To wit, it
seems that in the case of a type like
struct Foo {
1: required Enum E x = E.A
}
(for some enum E), the t_const_value that represents the initializer, ends
up having both a "identifier_val" and an "enum_val". And yet, in
plugin.thrift, it's a UNION.
So looking further, it seems that the (at least C++) code of a union, e.g.
union Bar {
1: i32 a ;
2: string b;
}
DOES NOT enforce the rule (from https://thrift.apache.org/docs/idl) that
Unions are similar to structs, except that they provide a means to
transport exactly one field of a possible set of fields, just like union {}
in C++. Consequently, union members are implicitly considered optional (see
requiredness).
In no way, is there any enforcement of "exactly one field".
It seems to me that this needs fixing. But it's a possibly- breaking
change.
I can starting fixing it in C++, Python, Ocaml, and a few other languages.
Should I do so?
--chet--
