Cannot use cpan/cpanm to build Perl modules #867

jacoby opened this Issue Aug 11, 2016 · 5 comments


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jacoby commented Aug 11, 2016 edited

Please use the following bug reporting template to help produce actionable and reproducible issues:

  • A brief description

Perl devs often use cpan to build/install modules where no .deb exists or the .deb is much older than the current one. I tried to use cpanm to install YAML::XS, and it failed tests, specifically relating to newlines. I use Ubuntu 14.04 LTS and cpan, and can assert this passes there.

cpanm YAML::XS
  • Expected results

A working YAML::XS module.

  • Actual results (with terminal output if applicable)

log file in a gist linked below. Errors come at lines 146, 162 and 207. This package installs flawlessly on other systems, including Strawberry Perl on the same machine.

  • Your Windows build number


  • Steps / commands required to reproduce the error

sudo apt-get install cpanm
sudo cpanm YAML::XS

  • Strace of the failing command
  • Required packages and commands to install

cpanm (A faster version of Perl's cpan command)

See our contributing instructions for assistance.

jacoby commented Aug 11, 2016 edited

Log exists as a Github Gist:

Errors are on lines 146, 162 and 207.

mbeijen commented Sep 25, 2016 edited

Hi @jacoby
You can't install the module because File::Find can not recurse directories on the file system that is in use by Ubuntu on Windows.

The solution is to edit

sudo vi /usr/lib/perl/5.18.2/

Set dont_use_nlink to 'define':

dont_use_nlink => 'define',

Now it's possible to install all modules you want!
(this is a duplicate of #186)

wyoung commented Oct 5, 2016

For 16.04, the correct path to edit is /usr/lib/x86_64-linux-gnu/perl/5.22.1/

Given that this reflects a fundamental difference between Windows and "real" Ubuntu Linux, shouldn't WSL Perl ship with this patch already in place? I get that the project is trying to use upstream packages untouched, but does the WSL project really want to make all Perl users hand-hack their install to allow cpanm and such to work?

I wouldn't be asking if this weren't a long-term problem with a simple, known solution, which has just bitten me for the second time.

mbeijen commented Oct 5, 2016

I'd also very much like an 'upstream' patch from Ubuntu/Microsoft here!


See #910 and #186. Either WSL or perl will fix this, depending on where the fix should live. I thought File::Find, but after seeing 910 I'm no longer so sure.

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