Safe navigation

.rubocop.yml

     - 'app/models/token.rb'
     - 'app/models/user.rb'
 
-# Offense count: 3
-# Cop supports --auto-correct.
-# Configuration parameters: ConvertCodeThatCanStartToReturnNil, Whitelist.
-# Whitelist: present?, blank?, presence, try, try!
-Style/SafeNavigation:
-  Exclude:
-    - 'app/controllers/authentication_controller.rb'
-    - 'app/models/person.rb'
-
 # Offense count: 215
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle, ConsistentQuotesInMultiline.
     - 'app/models/member.rb'
     - 'db/migrate/20180904163645_generate_calendar_tokens.rb'
 
-# Offense count: 1
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyleForMultiline.
-# SupportedStylesForMultiline: comma, consistent_comma, no_comma
-Style/TrailingCommaInArguments:
-  Exclude:
-    - 'app/models/activity.rb'
-
 # Offense count: 3
 # Cop supports --auto-correct.
 # Configuration parameters: WordRegex.

app/controllers/authentication_controller.rb

     else
       u = User.find_by(email: params[:session][:email])
 
-      if u && u.confirmed && u.authenticate(params[:session][:password])
+      if u&.confirmed && u&.authenticate(params[:session][:password])
         log_in(u, params[:session][:remember_me].to_i)
 
         flash_message(:success, I18n.t(:greeting, name: u.person.first_name))
     end
 
     user = User.find_by(person: person)
-    if user && user.confirmed
+    if user&.confirmed
       flash_message(:warning, I18n.t('authentication.already_activated'))
       redirect_to action: 'login'
       return

app/models/activity.rb

     people.each do |p|
       Participant.create(
         activity: self,
-        person: p,
+        person: p
       )
     end
   end

app/models/person.rb

   # Ensure the person's user email is updated at the same time as the person's
   # email.
   def update_user_email
-    unless self.user.nil?
-      self.user.update!(email: self.email)
-    end
+    self.user&.update!(email: self.email)
   end
 end