How do I make Alien use an existing tarball instead of downloading? - perl

Question

My distro does not offer any gsl <2.6 any more.
Given:
Alien::GSL 1.01
/tmp/gsl-2.5.tar.gz
How do I force it to compile that gsl instead of downloading from GNU FTP version 2.6, which I already have on the system anyway but is not delectable to Math::GSL 0.40?
I unsuccessfully tried:
copying the tarball into the unpacked Alien::GSL base directory
messing with alien_repository
This is for a throw-away project. I'm okay with manual installation instructions and patching toolchain code.

Answer 1

ikegami found the decisive hint:
It looks like you can set protocol of local to use a local file
Tested step-by-step instructions, plus some additional work-arounds; to me it looks like the build systems of the two modules are buggy/insufficiently tested:
cpanm --look Alien::GSL
patch Build.PL
diff --git a/Build.PL b/Build.PL
index 32f3057..6537138 100644
--- a/Build.PL
+++ b/Build.PL
## -20,10 +20,9 ## my $builder = Alien::Base::ModuleBuild->new(
alien_name => 'gsl',
alien_repository => [
{
- protocol => 'ftp',
- host => 'ftp.gnu.org',
- location => '/gnu/gsl',
- pattern => qr/^gsl-([\d\.]+)\.tar\.gz$/,
+ protocol => 'local',
+ location => '/tmp',
+ pattern => 'gsl-2.5.tar.gz',
},
],
meta_merge => {
--
2.23.0
perl Build.PL
./Build
Pay attention to the generated configure/libtool commands here, they match the Perl configuration. A manual installation without those various options is not guaranteed to be compatible or usable. (This is not superstition: a similar problem historically shows up when installing mod_perl2 and libapreq2 from source on a system httpd; perl needs to be compiled first, then httpd to match, then the other packages, otherwise it won't work.) This shows the value of installing through Alien, since it delegates to M::B, the correct options will be figured out. It's above my level of knowledge to accurately create them from scratch.
./Build test
gsl-config in blib now erroneously contains build paths, not install paths, fix:
perl -MConfig -i -lpe'
s|/.*(/auto/share/dist/Alien-GSL)|$Config{installsitelib}$1|
' blib/lib/auto/share/dist/Alien-GSL/bin/gsl-config
./Build install
exit # cpanm
cpanm --look Math::GSL
# let it pick up gsl-config on PATH
export PATH=$PATH:$(perl -mAlien::GSL -e'print Alien::GSL->bin_dir')
perl Build.PL
./Build
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$(gsl-config --libs | perl -lne'/-L(\S+) / && print $1')
./Build test
./Build install
exit # cpanm
Finally rëexport the variables whenever you want to use Math::GSL.