Building Rakudo Perl 6 For Arch Linux

One of my favorite features of my Linux distribution of choice, Arch Linux, is its package manager and the ecosystem built around it. I maintain my own repository of packages; some are custom builds of packages available in the standard repositories (like Vim), others are packages that don't exist in the standard repositories at all. One of the packages I maintain is for Rakudo Star, a Perl 6 distribution. I encountered some troubles creating a pacman package for the September release of Rakudo Star. I thought I would share my experiences so other package maintainers could learn from them.

The PKGBUILD I was using was copied from one I found on the AUR, and it was fairly straightforward:

perl Configure.pl --prefix=/usr
make
make install DESTDIR="$pkgdir"

However, while this used to work, it does not with the September release of Rakudo Star. I'll be describing the steps I went through to successfully create a package.

Fixing PERL6LIB

The first error message you see in the make install output is the following (plus a a lot more):

Could not find XML::Writer in any of: /home/rob/.perl6/lib, /usr/lib/parrot/4.8.0/languages/perl6/lib

After looking at this message, I realized that the installation process was expecting XML::Writer to have been installed to its permanent location, rather than to the staging area under DESTDIR. So fixing this was actually pretty easy:

# Before make install
export PERL6LIB="$pkgdir$(parrot_config libdir)$(parrot_config versiondir)/languages/perl6/lib"

Telling NQP Where To Find Perl6/Grammar.pbc

After adding that line to the PKGBUILD, I ran makepkg again, to find yet another error message:

/usr/bin/nqp --vmlibs=perl6_group,perl6_ops --target=pir \
  --output=modules/rakudo-debugger/perl6-debug.pir modules/rakudo-debugger/bin/perl6-debug.nqp
"load_bytecode" couldn't find file 'Perl6/Grammar.pbc'

Hooray! Something different! That must mean I made progress. In this line, you can see a program called "nqp" being invoked. NQP (or Not Quite Perl) is a minimalistic Perl 6 implementation used with the Parrot compiler tools to implement compilers for languages for the Parrot platform. From the error message, you can see that NQP is looking for a file called 'Perl6/Grammar.pbc', but isn't finding it. That file is the Perl 6 grammar that NQP uses to parse Perl 6 files. After looking at the NQP source code a bit, I couldn't find a good way to tell NQP where to find modules (PERL6LIB doesn't seem to work on NQP), but I did notice that in addition to system directories, NQP automatically searches for modules relative to the working directory. It's a dodgy hack, but I managed to fix this error by creating a symlink to the module directory under the working directory:

# again, put this before make install
if [[ -e Perl6 ]]; then
  unlink Perl6 # don't break successive builds
fi
ln -s "$pkgdir$(parrot_config libdir)$(parrot_config versiondir)/languages/nqp/lib/Perl6" .

Telling Parrot Where To Find perl_ops

After adding this and running makepkg yet again, I encountered this error after a few minutes of building:

/usr/bin/nqp --vmlibs=perl6_group,perl6_ops --target=pir \
  --output=modules/rakudo-debugger/perl6-debug.pir modules/rakudo-debugger/bin/perl6-debug.nqp
Could not load oplib `perl6_ops'

After looking under $pkgdir, I noticed a file named perl6_ops.so. I figured that the dynamic library loader was used to locate this file, so I just set LD_LIBRARY_PATH in my PKGBUILD:

# for the last time, before make install
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$pkgdir$(parrot_config libdir)$(parrot_config versiondir)/dynext"

It's important that I appended to LD_LIBRARY_PATH's existing value, because makepkg sets it up with some values and you don't want to break it.

After these three steps, however, I managed to get a working package of Rakudo Star built!

Fellow Archers, enjoy your shiny new Perl 6 installation! For you users of other distributions, please feel free to take what I've written here and make your own packages!

UPDATE: As of Rakudo Star 2013.01, the build process has been improved, so a perl Configure.PL/make/make install DESTDIR=$pkgdir style build process will work.