artifact_info url returned is packages.chef.io versus what is set in PACKAGE_ROUTER_ENDPOINT environment variable

Version:

v3.11.2

Environment:

RHEL 5 + Chef 12.22.5

Scenario:

I am trying to use a mirror (behind corporate firewall) by using the PACKAGE_ROUTER_ENDPOINT environment variable so that artifact URLs returned are the mirror URL instead of packages.chef.io URL.

Steps to Reproduce:

$ chef exec irb
irb(main):001:0> require 'mixlib/install'
=> true
irb(main):002:0> ENV['PACKAGE_ROUTER_ENDPOINT'] = 'https://packages-mirror.domain.com'
=> "https://packages-mirror.domain.com"
irb(main):003:0> Mixlib::Install.new({:product_name=>"chef", :platform_version_compatibility_mode=>true, :platform=>"el", :platform_version=>"5", :architecture=>"x86_64", :channel=>:stable, :product_version=>'13'}).artifact_info.url
=> "https://packages-mirror.domain.com/files/stable/chef/13.12.3/el/7/chef-13.12.3-1.el7.x86_64.rpm"
irb(main):004:0> Mixlib::Install.new({:product_name=>"chef", :platform_version_compatibility_mode=>true, :platform=>"el", :platform_version=>"5", :architecture=>"x86_64", :channel=>:stable, :product_version=>'13.6.4'}).artifact_info.url
=> "https://packages.chef.io/files/stable/chef/13.12.3/el/7/chef-13.12.3-1.el7.x86_64.rpm"
irb(main):005:0> Mixlib::Install::VERSION
=> "3.11.5"

Expected Result:

I would expect that the PACKAGE_ROUTER_ENDPOINT URL would be returned by artifact_info.url regardless of the options passed.

Actual Result:

When specifying a more specific version, it returns the packages.chef.io instead of the value of PACKAGE_ROUTER_ENDPOINT

Reproduce the issue with Mixlib::Install using PACKAGE_ROUTER_ENDPOINT, comparing artifact_info.url for a broad product version and a specific version. Start at the Mixlib::Install artifact_info URL path and trace how the endpoint is selected; done means both calls return URLs using the configured mirror, with tests covering the specific-version case.