rewrite linger to not do any prefetching

fixes: #302
fixes: #301

Author: trefzer

lib/puppet/provider/loginctl_user/ruby.rb

@@ -5,30 +5,18 @@
 # @see https://wiki.archlinux.org/title/Systemd/User
 Puppet::Type.type(:loginctl_user).provide(:ruby) do
   desc 'custom provider to manage systemd user sessions/linger'
-  commands loginctl: 'loginctl'
 
-  def self.instances
-    users = loginctl('list-users', '--no-legend').split("\n").map { |l| l.split[1] }
-    loginctl('show-user', '-p', 'Name', '-p', 'Linger', *users).split("\n\n").map do |u|
-      user = u.split("\n").to_h { |f| f.split('=') }
-      linger = if user['Linger'] == 'yes'
-                 'enabled'
-               else
-                 'disabled'
-               end
-      new(name: user['Name'],
-          linger: linger)
-    end
-  end
+  commands loginctl: 'loginctl'
 
-  def self.prefetch(resources)
-    instances.each do |prov|
-      resources[prov.name].provider = prov if resources[prov.name]
-    end
+  def linger
+    # loginctl is only successful if the user has an active session (so either logged in or lingering
+    # so if loginctl fails, linger is definitly disabled, for users with an active session
+    # (eg. logged in or running a timer or ...), the Linger property displays if lingering is activated.
+    :enabled if loginctl('show-user', resource[:name], '--property=Linger', '--value').chomp == 'yes'
+  rescue Puppet::ExecutionFailure
+    :disabled
   end
 
-  mk_resource_methods
-
   def linger=(value)
     case value
     when :enabled

spec/unit/puppet/provider/loginctl_user/ruby_spec.rb

@@ -13,20 +13,6 @@
     }
   end
 
-  context 'when listing instances' do
-    it 'finds all entries' do
-      allow(provider_class).to receive(:loginctl).
-        with('list-users', '--no-legend').
-        and_return("0 root\n42 foo\n314 bar\n")
-      allow(provider_class).to receive(:loginctl).
-        with('show-user', '-p', 'Name', '-p', 'Linger', 'root', 'foo', 'bar').
-        and_return("Name=root\nLinger=no\n\nName=foo\nLinger=yes\n\nName=bar\nLinger=no\n")
-      inst = provider_class.instances.map!
-
-      expect(inst.size).to eq(3)
-    end
-  end
-
   it 'enables linger' do
     resource = Puppet::Type.type(:loginctl_user).new(common_params)
     expect(provider_class).to receive(:loginctl).with('enable-linger', 'foo')