Add Env.with_clean_env for resetting the Ruby and Rubygems environment

lib/vagrant/util.rb

@@ -2,6 +2,7 @@ module Vagrant
   module Util
     autoload :Busy,                      'vagrant/util/busy'
     autoload :Counter,                   'vagrant/util/counter'
+    autoload :Env,                       'vagrant/util/env'
     autoload :HashWithIndifferentAccess, 'vagrant/util/hash_with_indifferent_access'
     autoload :Platform,                  'vagrant/util/platform'
     autoload :Retryable,                 'vagrant/util/retryable'

lib/vagrant/util/env.rb

@@ -0,0 +1,43 @@
+module Vagrant
+  module Util
+    class Env
+      #
+      # Execute the given command, removing any Ruby-specific environment
+      # variables. This is an "enhanced" version of `Bundler.with_clean_env`,
+      # which only removes Bundler-specific values. We need to remove all
+      # values, specifically:
+      #
+      # - _ORIGINAL_GEM_PATH
+      # - GEM_PATH
+      # - GEM_HOME
+      # - GEM_ROOT
+      # - BUNDLE_BIN_PATH
+      # - BUNDLE_GEMFILE
+      # - RUBYLIB
+      # - RUBYOPT
+      # - RUBY_ENGINE
+      # - RUBY_ROOT
+      # - RUBY_VERSION
+      #
+      # This will escape Vagrant's environment entirely, which is required if
+      # calling an executable that lives in another Ruby environment. The
+      # original environment restored at the end of this call.
+      #
+      # @param [Proc] block
+      #   the block to execute with the cleaned environment
+      #
+      def with_clean_env(&block)
+        original = ENV.to_hash
+
+        ENV.delete('_ORIGINAL_GEM_PATH')
+        ENV.delete_if { |k,_| k.start_with?('BUNDLE_') }
+        ENV.delete_if { |k,_| k.start_with?('GEM_') }
+        ENV.delete_if { |k,_| k.start_with?('RUBY') }
+
+        yield
+      ensure
+        ENV.replace(original.to_hash)
+      end
+    end
+  end
+end

plugins/provisioners/chef/provisioner/chef_client.rb

@@ -110,7 +110,7 @@ module VagrantPlugins
           # Knife is not part of the current Vagrant bundle, so it needs to run
           # in the context of the system.
           Vagrant.global_lock do
-            Bundler.with_clean_env do
+            Vagrant::Util::Env.with_clean_env do
               command = ["knife", deletable, "delete", "--yes", node_name]
               r = Vagrant::Util::Subprocess.execute(*command)
               if r.exit_code != 0