(maint) Read system custom facts when running as user

When Facter is run as a user, the system custom facts are not available.

Always take system custom facts into accound, and if Facter is running
as another user, prepend this user custom facts directories to the list
of search directories.

Author: smortex

lib/facter/custom_facts/util/config.rb

@@ -37,24 +37,23 @@ def self.facts_cache_dir
       end
 
       def self.setup_default_ext_facts_dirs
-        if LegacyFacter::Util::Root.root?
-          windows_dir = windows_data_dir
-          Facter::Options[:default_external_dir] = if windows_dir
-                                                     [File.join(windows_dir, 'PuppetLabs', 'facter', 'facts.d')]
-                                                   else
-                                                     [
-                                                       '/etc/puppetlabs/facter/facts.d',
-                                                       '/etc/facter/facts.d/',
-                                                       '/opt/puppetlabs/facter/facts.d'
-                                                     ]
-                                                   end
-        elsif ENV['HOME']
-          Facter::Options[:default_external_dir] =
-            [File.join(ENV['HOME'], '.facter', 'facts.d'),
-             File.join(ENV['HOME'], '.puppetlabs', 'opt', 'facter', 'facts.d')]
-        else
-          Facter::Options[:default_external_dir] = []
-        end
+        windows_dir = windows_data_dir
+        Facter::Options[:default_external_dir] = if windows_dir
+                                                   [File.join(windows_dir, 'PuppetLabs', 'facter', 'facts.d')]
+                                                 else
+                                                   [
+                                                     '/etc/puppetlabs/facter/facts.d',
+                                                     '/etc/facter/facts.d/',
+                                                     '/opt/puppetlabs/facter/facts.d'
+                                                   ]
+                                                 end
+
+        return unless !LegacyFacter::Util::Root.root? && ENV['HOME']
+
+        Facter::Options[:default_external_dir].prepend(
+          File.join(ENV['HOME'], '.facter', 'facts.d'),
+          File.join(ENV['HOME'], '.puppetlabs', 'opt', 'facter', 'facts.d')
+        )
       end
 
       if LegacyFacter::Util::Config.windows?

spec/custom_facts/util/config_spec.rb

@@ -6,19 +6,6 @@
 describe LegacyFacter::Util::Config do
   include PuppetlabsSpec::Files
 
-  describe "ENV['HOME'] is unset", unless: LegacyFacter::Util::Root.root? do
-    around do |example|
-      Facter::Core::Execution.with_env('HOME' => nil) do
-        example.run
-      end
-    end
-
-    it 'does not set @external_facts_dirs' do
-      LegacyFacter::Util::Config.setup_default_ext_facts_dirs
-      expect(LegacyFacter::Util::Config.external_facts_dirs).to be_empty
-    end
-  end
-
   describe 'is_windows? function' do
     it "detects windows if Ruby RbConfig::CONFIG['host_os'] returns a windows OS" do
       host_os = %w[mswin win32 dos mingw cygwin]
@@ -85,7 +72,10 @@
       LegacyFacter::Util::Config.setup_default_ext_facts_dirs
       expect(LegacyFacter::Util::Config.external_facts_dirs)
         .to eq [File.join(ENV['HOME'], '.facter', 'facts.d'),
-                File.join(ENV['HOME'], '.puppetlabs', 'opt', 'facter', 'facts.d')]
+                File.join(ENV['HOME'], '.puppetlabs', 'opt', 'facter', 'facts.d'),
+                '/etc/puppetlabs/facter/facts.d',
+                '/etc/facter/facts.d/',
+                '/opt/puppetlabs/facter/facts.d']
     end
 
     it 'includes additional values when user appends to the list' do