Fix unsupported time zone or locale preventing sign-up

app/models/user.rb

@@ -96,11 +96,9 @@ class User < ApplicationRecord
   accepts_nested_attributes_for :invite_request, reject_if: ->(attributes) { attributes['text'].blank? && !Setting.require_invite_text }
   validates :invite_request, presence: true, on: :create, if: :invite_text_required?
 
-  validates :locale, inclusion: I18n.available_locales.map(&:to_s), if: :locale?
   validates_with BlacklistedEmailValidator, if: -> { ENV['EMAIL_DOMAIN_LISTS_APPLY_AFTER_CONFIRMATION'] == 'true' || !confirmed? }
   validates_with EmailMxValidator, if: :validate_email_dns?
   validates :agreement, acceptance: { allow_nil: false, accept: [true, 'true', '1'] }, on: :create
-  validates :time_zone, inclusion: { in: ActiveSupport::TimeZone.all.map { |tz| tz.tzinfo.name } }, allow_blank: true
 
   # Honeypot/anti-spam fields
   attr_accessor :registration_form_time, :website, :confirm_password
@@ -124,6 +122,8 @@ class User < ApplicationRecord
 
   before_validation :sanitize_languages
   before_validation :sanitize_role
+  before_validation :sanitize_time_zone
+  before_validation :sanitize_locale
   before_create :set_approved
   after_commit :send_pending_devise_notifications
   after_create_commit :trigger_webhooks
@@ -451,9 +451,15 @@ def sanitize_languages
   end
 
   def sanitize_role
-    return if role.nil?
+    self.role = nil if role.present? && role.everyone?
+  end
+
+  def sanitize_time_zone
+    self.time_zone = nil if time_zone.present? && ActiveSupport::TimeZone[time_zone].nil?
+  end
 
-    self.role = nil if role.everyone?
+  def sanitize_locale
+    self.locale = nil if locale.present? && I18n.available_locales.exclude?(locale.to_sym)
   end
 
   def prepare_new_user!

spec/controllers/settings/preferences/appearance_controller_spec.rb

@@ -28,11 +28,5 @@
 
       expect(response).to redirect_to(settings_preferences_appearance_path)
     end
-
-    it 'renders show on failure' do
-      put :update, params: { user: { locale: 'fake option' } }
-
-      expect(response).to render_template('preferences/appearance/show')
-    end
   end
 end

spec/models/user_spec.rb

@@ -27,12 +27,6 @@
       expect(user).to model_have_error_on_field(:account)
     end
 
-    it 'is invalid without a valid locale' do
-      user = Fabricate.build(:user, locale: 'toto')
-      user.valid?
-      expect(user).to model_have_error_on_field(:locale)
-    end
-
     it 'is invalid without a valid email' do
       user = Fabricate.build(:user, email: 'john@')
       user.valid?