Rebuild failing after adding discourse-saml plugin

After adding the discourse-saml plugin, when running ./launcher rebuild app we’re seeing the following fatal error:

ERROR:  While executing gem ... (TypeError)
    no implicit conversion of nil into String
I, [2017-07-26T18:49:17.968340 #7]  INFO -- : gem install macaddr -v 1.0.0 -i /var/www/discourse/plugins/discourse-saml/gems/2.4.1 --no-document --ignore-dependencies

You are specifying the gem macaddr in /var/www/discourse/plugins/discourse-saml/plugin.rb, however it does not exist!

The discourse-saml plugin.rb does indeed express some gem dependencies. By the looks of the above INFO message, it is supposed to try to install for itself, but it just stops immediately. Possibly because of the earlier(? are these log messages actually in order?) error about “no implicit conversion of nil into String”.

Anyone know what’s wrong with this?


It looks like this process worked correctly if I had HTTP(S)_PROXY (and lowercase) correctly defined for the whole installation process rather than just the parts that I thought needed it.