Re: plperl fails with perl 5.28

Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com> writes:
> On 05/22/2018 07:18 AM, Christoph Berg wrote:
>> plperl fails to install with perl 5.27.11, which is to be released as 5.28.0:

> I have a tiny bit more info:
> andrew=# load 'plperl.so';
> ERROR:
> CONTEXT: while running Perl initialization
> andrew=#

I get the same behavior with a build of 5.27.11 on Fedora 28.

> That means it's failing at line 860 of plperl.c.

Tracing through it, the problem is that perl_run is returning 0x100,
rather than zero as we expect, even though there was no failure.
This happens because perl.c:S_run_body() falls off the end of the
initialization code and does "my_exit(0);". Apparently it's done that for
a long time, but what's new is that perl_run() does this in response
after catching the longjmp from my_exit():

if (exit_called) {
ret = STATUS_EXIT;
if (ret == 0) ret = 0x100;
} else {
ret = 0;
}

That traces to this recent commit:

https://perl5.git.perl.org/perl.git/commitdiff/0301e899536a22752f40481d8a1d141b7a7dda82

which seems rather brain-dead from here, because it claims that it's
defining perl_run's result as a truth value, which it is not any more.

So assuming that this holds and the Perl guys don't see the error
of their ways, we'd need something like this, I think:

- if (perl_run(plperl) != 0)
+ if ((perl_run(plperl) & 0xFF) != 0)

but TBH I think someone oughta file a bug report first. They can't
seriously intend that callers must do that, especially when there does
not seem to be any big bold warning about it in perl*delta.pod.

(Also, since perl_parse and perl_run are now specified to have identical
return conventions, we'd probably want to change the perl_parse call
likewise, even though it's not failing today.)

(Alternatively, perhaps it's a bad idea that the plperl initialization
script falls off the end rather than explicitly returning?)

regards, tom lane