Re: pl/perl extension fails on Windows

On Wed, Jul 19, 2017 at 05:01:31PM -0400, Tom Lane wrote:
> Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com> writes:
> > Here are the list of macros and variables from 'intrpvar.h' file that
> > are just defined in perl module but not in plperl on Windows,
>
> > #ifdef PERL_USES_PL_PIDSTATUS
> > PERLVAR(I, pidstatus, HV *) /* pid-to-status mappings for waitpid */
> > #endif
>
> > #ifdef PERL_SAWAMPERSAND
> > PERLVAR(I, sawampersand, U8) /* must save all match strings */
> > #endif
>
> I am really suspicious that this means your libperl was built in an unsafe
> fashion, that is, by injecting configuration choices as random -D switches
> in the build process rather than making sure the choices were recorded in
> perl's config.h. As an example, looking at the perl 5.24.1 headers on
> a Fedora box, it looks to me like PERL_SAWAMPERSAND could only get defined
> if PERL_COPY_ON_WRITE were not defined, and the only way that that can
> happen is if PERL_NO_COW is defined, and there are no references to the
> latter anyplace except in this particular #if defined test in perl.h.
>
> Where did your perl installation come from, anyway? Are you sure the .h
> files match up with the executables?

I see corresponding symptoms with the following Perl distributions:

strawberry-perl-5.26.0.1-64bit.msi:
src/pl/plperl/Util.c: loadable library and perl binaries are mismatched (got handshake key 0000000011800080, needed 0000000011c00080)
ActivePerl-5.24.1.2402-MSWin32-x64-401627.exe:
src/pl/plperl/Util.c: loadable library and perl binaries are mismatched (got handshake key 0000000011500080, needed 0000000011900080)

So, this affects each of the two prominent families of Perl Windows binaries.
Notes for anyone trying to reproduce:

- Both of those Perl distributions require the hacks described here:
https://www.postgresql.org/message-id/flat/CABcP5fjEjgOsh097cWnQrsK9yCswo4DZxp-V47DKCH-MxY9Gig%40mail.gmail.com
- Add PERL_USE_UNSAFE_INC=1 to the environment until we update things to cope
with this Perl 5.26 change:
http://search.cpan.org/~xsawyerx/perl-5.26.0/pod/perldelta.pod#Removal_of_the_current_directory_(%22.%22)_from_(at)INC