Some time ago, I wrote about Environment Leakage, and I'm happy to report that this is much less of a problem today. As of Puppet 4.8 and Puppet Enterprise 2016.5, most custom types will no longer be subject to environment leakage. It's transparent for the end user, when Puppet Enterprise Code Manager is configured, and can be used in Puppet Open Source by following the documentation.
Welcome back; gather 'round. Today we're going to talk about a topic we've all been wondering how to bring up. We'll be talking about leakage--no, not that kind of leakage! (Those of you too young to get that joke are highly encouraged to not go look up the history of Olestra.)
Update: In many cases, environments no longer leak on Puppet 4.8 and above.