Based on the conversation at [1]. This caches the Perl site directory after we've installed IPC::Run. After consulting with Christoph Berg and David Wheeler on the Discord, I've set up the cache to key on the output of `perl -V`, so that we'll rebuild it after any change to Perl underneath us.
I went back and forth on doing the bare minimum (just save off the CPAN source+build caches, then run CPAN each time) vs the more involved strategy presented here (don't use CPAN at all on a cache hit). The simpler approach only saved us about half of the up-to-60s installation delay, because I can't seem to get CPAN to skip the installation if IPC::Run is already installed. So this patch is more code, but it's a lot faster once the cache is warm. (The cache is also much smaller, as a minor bonus, but it was only ~3MB to start with.) --Jacob [1] https://postgr.es/m/CAOYmi%2BkyuJHC7NTJWbzLBX25QnCsMVDbYWmv5tveSveNUyBAUw%40mail.gmail.com
0001-ci-Cache-the-CPAN-installation-on-Windows-runners.patch
Description: Binary data
