Handle user create race condition

Fixes ManageIQ#20041

app/models/authenticator/base.rb

@@ -137,7 +137,18 @@ def authorize(taskid, username, *args)
  end
 
  user.lastlogon = Time.now.utc
- user.save!
+ if user.new_record?
+ User.with_lock do
+ user.save!
+ rescue ActiveRecord::RecordInvalid # Try update when catching create race condition.
+ userid, user = find_or_initialize_user(identity, username)
+ update_user_attributes(user, userid, identity)
+ user.miq_groups = matching_groups
+ user.save!
+ end
+ else
+ user.save!
+ end
 
  _log.info("Authorized User: [#{user.userid}]")
  task.userid = user.userid

spec/models/authenticator/httpd_spec.rb

@@ -272,6 +272,18 @@ def authenticate
  'X-Remote-User-Email' => 'Sally@example.com')
  end
 
+ context "with a race condition on create user" do
+ before do
+ authenticate
+ end
+
+ it "update the exiting user" do
+ allow(User).to receive(:lookup_by_userid).and_return(nil)
+ allow(User).to receive(:in_my_region).and_return(User.none, User.all)
+ expect { authenticate }.not_to(change { User.where(:userid => 'sally@example.com').count }.from(1))
+ end
+ end
+
  context "when user record with userid in upn format already exists" do
  let!(:sally_username) { FactoryBot.create(:user, :userid => 'sAlly') }
  let!(:sally_dn) { FactoryBot.create(:user, :userid => dn) }