Bug#578547: libdata-alias-perl: FTBFS with Perl 5.12: 'Nullsv' undeclared

[Niko Tyni]

On Thu, Apr 22, 2010 at 09:12:22PM +0300, Niko Tyni wrote:
 
> I got as far as getting it to compile (patch attached) without breaking
> 5.10.1, but the tests segfault on 5.12.

I have some good and some bad news.

The bad news is that fixing the segfaults looks far from trivial.
The Perl change that broke this is probably
 http://perl5.git.perl.org/perl.git/commit/f7461760003db2ce68155c97ea6c1658e96fcd27

AIUI, Data::Alias hooks onto OP_RV2CV and modifies the parser state, but
the change makes the rv2cv op get generated earlier and the modifications
break. I doubt I'll be able to put a fix together (but I haven't quite
given up yet.)

The good news is that the only direct reverse dependency,
libdata-visitor-perl, only uses Data::Alias::deref(), which works fine
with 5.12. Furthermore, it's really a soft dependency and the relevant
tests are skipped if Data::Alias is not installed.

This gives us a few new options, assuming libdata-alias-perl doesn't
get fixed in time (or at all):

A: disable the test suite in libdata-alias-perl and ship a package
   that works just 'well enough'

B: remove libdata-alias-perl from the archive: either
  B1. remove the libdata-visitor-perl dependency on libdata-alias-perl
    and hope that no libdata-visitor-perl reverse dependencies need
    the removed functionality
 OR
  B2. split Data::Alias::deref() out into a new package and make
    libdata-visitor-perl use that.
 OR
  B3. find another dereferencing implementation and make
    libdata-visitor-perl use that.

B2 or B3 are the only options that look "right" to me.

Obviously upstream should be involved.
-- 
Niko Tyni   ntyni at debian.org