Fixes #3818 - Owner should get cleared if not listed in changed group.

app/models/core_workflow/attributes.rb

@@ -238,13 +238,10 @@ class CoreWorkflow::Attributes
   end
 
   def saved_attribute_value(attribute)
-    saved_attribute_value = saved_only&.try(attribute[:name])
 
     # special case for owner_id
-    if saved_only&.class == Ticket && attribute[:name] == 'owner_id' && saved_attribute_value == 1
-      saved_attribute_value = nil
-    end
+    return if saved_only&.class == Ticket && attribute[:name] == 'owner_id'
 
-    saved_attribute_value
+    saved_only&.try(attribute[:name])
   end
 end

spec/system/ticket/update_spec.rb

@@ -322,10 +322,10 @@ RSpec.describe 'Ticket Update', type: :system do
   end
 
   context 'when group will be changed' do
-    let(:user) { create(:user) }
+    let(:user) { User.find_by(email: 'agent1@example.com') }
     let(:ticket) { create(:ticket, group: group, owner: user) }
 
-    it 'check that owner is resetet after group change' do
+    it 'check that owner resets after group change' do
       visit "#ticket/zoom/#{ticket.id}"
 
       expect(page).to have_field('owner_id', with: user.id)

spec/system/ticket/zoom_spec.rb

@@ -2235,4 +2235,36 @@ RSpec.describe 'Ticket zoom', type: :system do
       expect(page).to have_selector('form.article-add.is-open')
     end
   end
+
+  context 'Owner should get cleared if not listed in changed group #3818', authenticated_as: :authenticate do
+    let(:group1) { create(:group) }
+    let(:group2) { create(:group) }
+    let(:agent1) { create(:agent) }
+    let(:agent2) { create(:agent) }
+    let(:ticket) { create(:ticket, group: group1, owner: agent1) }
+
+    def authenticate
+      agent1.group_names_access_map = {
+        group1.name => 'full',
+        group2.name => %w[read change overview]
+      }
+      agent2.group_names_access_map = {
+        group1.name => 'full',
+        group2.name => 'full',
+      }
+      agent1
+    end
+
+    before do
+      visit "#ticket/zoom/#{ticket.id}"
+    end
+
+    it 'does clear agent1 on select of group 2' do
+      select group2.name, from: 'Group'
+      wait(5).until { page.find('select[name=owner_id]').value != agent1.id.to_s }
+      expect(page.find('select[name=owner_id]').value).to eq('')
+      expect(page.all('select[name=owner_id] option').map(&:value)).not_to include(agent1.id.to_s)
+      expect(page.all('select[name=owner_id] option').map(&:value)).to include(agent2.id.to_s)
+    end
+  end
 end