symbol::read_archive(): explicitly set status_flags::evaluated (and
status_flags::expanded) on object being unarchived. These flags get
reset by basic::operator=(const basic&) for realsymbol and possymbol,
and nothing sets (except symbol ctor), so automatic evaluation never
terminates (or rather, terminates due to a stack overflow). Therefore
it's necessary need to set status_flags::evaluated explicitly.
Thanks to Markus Fröb for a bugreport and a test case.
(cherry picked from commit
e99d0d58c1bbaa8ee73e4a90a90aa1086f2f813d)
for (lst::const_iterator it = sym_lst.begin(); it != sym_lst.end(); ++it) {
if (is_a<symbol>(*it) && (ex_to<symbol>(*it).name == tmp_name)) {
*this = ex_to<symbol>(*it);
+ // XXX: This method is responsible for reading realsymbol
+ // and possymbol objects too. But
+ // basic::operator=(const basic& other)
+ // resets status_flags::evaluated if other and *this are
+ // of different types. Usually this is a good idea, but
+ // doing this for symbols is wrong (for one, nothing is
+ // going to set status_flags::evaluated, evaluation will
+ // loop forever). Therefore we need to restore flags.
+ setflag(status_flags::evaluated | status_flags::expanded);
return;
}
}