How to install cpanm with github action workflow with linux runner? - perl

Question

I am not able to install cpanm with this simple workflow:
name: linux-cpanm-test
on: [push, pull_request]
jobs:
build-dist:
runs-on: ubuntu-20.04
steps:
- uses: actions/checkout#v2
- name: perl info
run: |
perl --version
- name: install cpanm
run: cpan App::cpanminus
- name: test cpanm
run: cpanm -v Path::Tiny
Here is a link to the test repository. As can be seen, cpan App::cpanminus fails with:
Use of uninitialized value $_[0] in substitution (s///) at /usr/share/perl/5.30/File/Basename.pm line 341.
fileparse(): need a valid pathname at /usr/share/perl/5.30/CPAN/FirstTime.pm line 1413.
Error: Process completed with exit code 255.
Any ideas what can be the problem?

Answer 1

I've been using shogu82148/actions-setup-perl. That installs cpanm for me and I've never had any problems.
The jobs section of my workflow files look like this:
jobs:
build:
runs-on: ${{ matrix.os }}
strategy:
matrix:
os: ['ubuntu-latest', 'macos-latest', 'windows-latest']
perl: [ 'latest' ]
name: Perl ${{ matrix.perl }} on ${{ matrix.os }}
steps:
- uses: actions/checkout#v2
- name: Set up perl
uses: shogo82148/actions-setup-perl#v1
with:
perl-version: ${{ matrix.perl }}
- run: perl -V
- run: cpanm --installdeps .
- run: prove -lv t

Answer 2

In my Github workflows, I don't use cpan to install cpanminus. I've run into issues with openssl on the ubuntu hosts.
- name: Install cpanm and multiple modules
run: |
curl -L https://cpanmin.us | perl - App::cpanminus
cpanm --notest ...
But, I also break my workflows for different platforms into separate files. See PerlPowerTools/.github/workflows for instance. That one is not very complicated.
I don't spend the time to try to make them all act like each other—that's too much complexity. I don't want to debug someone's action when it's not doing exactly what I want. Also, when one platform has a problem, I can create a branch and trigger just that platform on that branch. You might be able to do that with a single file runner too, but that's too much complexity for me to want to manage.
Also, I've had lots of spurious failures with CPAN mirrors with a bare call to cpan. I've updated all of my actions to point to the CDN version of CPAN and haven't seen that problem since:
cpan -M https://www.cpan.org ...
And, lately I've been careful to install dependencies first using the "no test" features of either client. This mostly saves a lot of time. After that, I then run the tests for my module:
cpanm --notest ...
cpan -T ...

Answer 3

It seems that cpan App::cpanminus tries to install local::lib into /home/runner/perl5/. I tried to bootstrap local::lib manually to $GITHUB_WORKSPACE/perl5 instead. This seems to fix the problem (I am not sure why, but I guess it has to do with permissions):
name: linux-cpanm-test
on: [push, pull_request]
jobs:
build-dist:
runs-on: ubuntu-20.04
steps:
- uses: actions/checkout#v2
- name: perl info
run: |
perl --version
- name: setup locallib
run: |
tempdir=$(mktemp -d)
cd $tempdir
wget https://cpan.metacpan.org/authors/id/H/HA/HAARG/local-lib-2.000024.tar.gz
tar zxvf local-lib-2.000024.tar.gz
cd local-lib-2.000024
PERL_LOCAL_LIB_ROOT=$GITHUB_WORKSPACE/perl5
perl Makefile.PL --bootstrap=$PERL_LOCAL_LIB_ROOT
make
make test
echo "PERL_LOCAL_LIB_ROOT=$PERL_LOCAL_LIB_ROOT" >> $GITHUB_ENV
echo "PERL5LIB=$PERL_LOCAL_LIB_ROOT/lib/perl5" >> $GITHUB_ENV
echo "PERL_MB_OPT=--install_base \"$PERL_LOCAL_LIB_ROOT/\"" >> $GITHUB_ENV
echo "PERL_MM_OPT=INSTALL_BASE=$PERL_LOCAL_LIB_ROOT" >> $GITHUB_ENV
echo "PATH=$PERL_LOCAL_LIB_ROOT/bin:$PATH" >> $GITHUB_ENV
- name: install cpanm
run: cpan App::cpanminus
- name: test cpanm
run: cpanm -v Path::Tiny
Here is a link to the new build log, showing that it now works.
Edit:
Here is a simplified workflow file as suggested by #ikegami. This also works:
name: linux-cpanm-test
on: [push, pull_request]
jobs:
build-dist:
runs-on: ubuntu-20.04
steps:
- uses: actions/checkout#v2
- name: perl info
run: |
perl --version
- name: setup locallib
run: |
PERL_LOCAL_LIB_ROOT="$HOME/perl5"
>>"$GITHUB_ENV" echo "PERL_LOCAL_LIB_ROOT=$PERL_LOCAL_LIB_ROOT"
>>"$GITHUB_ENV" echo "PERL5LIB=$PERL_LOCAL_LIB_ROOT/lib/perl5"
>>"$GITHUB_ENV" echo "PERL_MB_OPT=--install_base \"$PERL_LOCAL_LIB_ROOT/\""
>>"$GITHUB_ENV" echo "PERL_MM_OPT=INSTALL_BASE=$PERL_LOCAL_LIB_ROOT"
>>"$GITHUB_ENV" echo "PATH=$PERL_LOCAL_LIB_ROOT/bin:$PATH"
- name: install cpanm
run: cpan App::cpanminus
- name: test cpanm
run: cpanm -v Path::Tiny
Here is the log.