Bumps [rails](https://github.com/rails/rails) from 5.1.7 to 5.2.3.

- [Release notes](https://github.com/rails/rails/releases) - [Changelog](https://github.com/rails/rails/blob/master/CHANGELOG.md) - [Commits](https://github.com/rails/rails/compare/v5.1.7...v5.2.3)
2019-07-04 13:16:55 +02:00 · 2019-07-04 13:16:55 +02:00 · 5745fa46bd
commit 5745fa46bd
parent c788c3e053
70 changed files with 648 additions and 316 deletions
--- a/.rubocop.yml
+++ b/.rubocop.yml
@ -268,3 +268,11 @@ Layout/MultilineMethodCallIndentation:
 Style/HashSyntax:
  Exclude:
    - "**/*.rake"
+
+Rails/Exit:
+  Exclude:
+    - "config/initializers/*.rb"
+
+Rails/Output:
+  Exclude:
+    - "config/initializers/*.rb"
--- a/3
+++ b/3
@ -2,11 +2,12 @@ source 'https://rubygems.org'

 # core - base
 ruby '2.5.5'
-gem 'rails', '5.1.7'
+gem 'rails', '5.2.3'

 # core - rails additions
 gem 'activerecord-import'
 gem 'activerecord-session_store'
+gem 'bootsnap', require: false
 gem 'composite_primary_keys'
 gem 'json'
 gem 'rails-observers'
--- a/Gemfile.lock
+++ b/Gemfile.lock
@ -49,39 +49,39 @@ GEM
  specs:
    aasm (5.0.0)
      concurrent-ruby (~> 1.0)
-    actioncable (5.1.7)
-      actionpack (= 5.1.7)
+    actioncable (5.2.3)
+      actionpack (= 5.2.3)
      nio4r (~> 2.0)
-      websocket-driver (~> 0.6.1)
-    actionmailer (5.1.7)
-      actionpack (= 5.1.7)
-      actionview (= 5.1.7)
-      activejob (= 5.1.7)
+      websocket-driver (>= 0.6.1)
+    actionmailer (5.2.3)
+      actionpack (= 5.2.3)
+      actionview (= 5.2.3)
+      activejob (= 5.2.3)
      mail (~> 2.5, >= 2.5.4)
      rails-dom-testing (~> 2.0)
-    actionpack (5.1.7)
-      actionview (= 5.1.7)
-      activesupport (= 5.1.7)
+    actionpack (5.2.3)
+      actionview (= 5.2.3)
+      activesupport (= 5.2.3)
      rack (~> 2.0)
      rack-test (>= 0.6.3)
      rails-dom-testing (~> 2.0)
      rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (5.1.7)
-      activesupport (= 5.1.7)
+    actionview (5.2.3)
+      activesupport (= 5.2.3)
      builder (~> 3.1)
      erubi (~> 1.4)
      rails-dom-testing (~> 2.0)
      rails-html-sanitizer (~> 1.0, >= 1.0.3)
-    activejob (5.1.7)
-      activesupport (= 5.1.7)
+    activejob (5.2.3)
+      activesupport (= 5.2.3)
      globalid (>= 0.3.6)
-    activemodel (5.1.7)
-      activesupport (= 5.1.7)
-    activerecord (5.1.7)
-      activemodel (= 5.1.7)
-      activesupport (= 5.1.7)
-      arel (~> 8.0)
-    activerecord-import (1.0.1)
+    activemodel (5.2.3)
+      activesupport (= 5.2.3)
+    activerecord (5.2.3)
+      activemodel (= 5.2.3)
+      activesupport (= 5.2.3)
+      arel (>= 9.0)
+    activerecord-import (1.0.2)
      activerecord (>= 3.2)
    activerecord-nulldb-adapter (0.3.9)
      activerecord (>= 2.0.0)
@ -91,16 +91,20 @@ GEM
      multi_json (~> 1.11, >= 1.11.2)
      rack (>= 1.5.2, < 3)
      railties (>= 4.0)
-    activesupport (5.1.7)
+    activestorage (5.2.3)
+      actionpack (= 5.2.3)
+      activerecord (= 5.2.3)
+      marcel (~> 0.3.1)
+    activesupport (5.2.3)
      concurrent-ruby (~> 1.0, >= 1.0.2)
      i18n (>= 0.7, < 2)
      minitest (~> 5.1)
      tzinfo (~> 1.1)
-    acts_as_list (0.9.16)
+    acts_as_list (0.9.19)
      activerecord (>= 3.0)
    addressable (2.5.2)
      public_suffix (>= 2.0.2, < 4.0)
-    arel (8.0.0)
+    arel (9.0.0)
    argon2 (2.0.2)
      ffi (~> 1.9)
      ffi-compiler (>= 0.1)
@ -112,6 +116,8 @@ GEM
    biz (1.8.2)
      clavius (~> 1.0)
      tzinfo
+    bootsnap (1.3.2)
+      msgpack (~> 1.0)
    browser (2.5.3)
    buftok (0.2.0)
    builder (3.2.3)
@ -141,8 +147,8 @@ GEM
      coffee-script
      execjs
      json
-    composite_primary_keys (10.0.5)
-      activerecord (~> 5.1.0, >= 5.1.6)
+    composite_primary_keys (11.2.0)
+      activerecord (~> 5.2.1)
    concurrent-ruby (1.1.5)
    coveralls (0.8.23)
      json (>= 1.8, < 3)
@ -156,7 +162,7 @@ GEM
    daemons (1.3.1)
    dalli (2.7.10)
    debug_inspector (0.0.3)
-    delayed_job (4.1.5)
+    delayed_job (4.1.7)
      activesupport (>= 3.0, < 5.3)
    delayed_job_active_record (4.1.3)
      activerecord (>= 3.0, < 5.3)
@ -268,17 +274,21 @@ GEM
      crass (~> 1.0.2)
      nokogiri (>= 1.5.9)
    lumberjack (1.0.13)
+    marcel (0.3.3)
+      mimemagic (~> 0.3.2)
    memoizable (0.4.2)
      thread_safe (~> 0.3, >= 0.3.1)
    method_source (0.9.2)
    mime-types (3.2.2)
      mime-types-data (~> 3.2015)
    mime-types-data (3.2019.0331)
+    mimemagic (0.3.3)
    mini_mime (1.0.1)
    mini_portile2 (2.4.0)
    mini_racer (0.2.4)
      libv8 (>= 6.3)
    minitest (5.11.3)
+    msgpack (1.2.4)
    multi_json (1.13.1)
    multi_xml (0.6.0)
    multipart-post (2.1.1)
@ -366,17 +376,18 @@ GEM
      rack
    rack-test (1.1.0)
      rack (>= 1.0, < 3)
-    rails (5.1.7)
-      actioncable (= 5.1.7)
-      actionmailer (= 5.1.7)
-      actionpack (= 5.1.7)
-      actionview (= 5.1.7)
-      activejob (= 5.1.7)
-      activemodel (= 5.1.7)
-      activerecord (= 5.1.7)
-      activesupport (= 5.1.7)
+    rails (5.2.3)
+      actioncable (= 5.2.3)
+      actionmailer (= 5.2.3)
+      actionpack (= 5.2.3)
+      actionview (= 5.2.3)
+      activejob (= 5.2.3)
+      activemodel (= 5.2.3)
+      activerecord (= 5.2.3)
+      activestorage (= 5.2.3)
+      activesupport (= 5.2.3)
      bundler (>= 1.3.0)
-      railties (= 5.1.7)
+      railties (= 5.2.3)
      sprockets-rails (>= 2.0.0)
    rails-controller-testing (1.0.4)
      actionpack (>= 5.0.1.x)
@ -389,12 +400,12 @@ GEM
      loofah (~> 2.2, >= 2.2.2)
    rails-observers (0.1.5)
      activemodel (>= 4.0)
-    railties (5.1.7)
-      actionpack (= 5.1.7)
-      activesupport (= 5.1.7)
+    railties (5.2.3)
+      actionpack (= 5.2.3)
+      activesupport (= 5.2.3)
      method_source
      rake (>= 0.8.7)
-      thor (>= 0.18.1, < 2.0)
+      thor (>= 0.19.0, < 2.0)
    rainbow (3.0.0)
    raindrops (0.19.0)
    rake (12.3.2)
@ -522,9 +533,9 @@ GEM
      addressable (>= 2.3.6)
      crack (>= 0.3.2)
      hashdiff
-    websocket-driver (0.6.5)
+    websocket-driver (0.7.1)
      websocket-extensions (>= 0.1.0)
-    websocket-extensions (0.1.3)
+    websocket-extensions (0.1.4)
    writeexcel (1.0.5)
    xpath (3.2.0)
      nokogiri (~> 1.8)
@ -548,6 +559,7 @@ DEPENDENCIES
  autodiscover!
  autoprefixer-rails
  biz
+  bootsnap
  browser
  byebug
  capybara
@ -602,7 +614,7 @@ DEPENDENCIES
  pry-stack_explorer
  puma
  rack-livereload
-  rails (= 5.1.7)
+  rails (= 5.2.3)
  rails-controller-testing
  rails-observers
  rb-fsevent
--- a/app/controllers/application_controller/prevents_csrf.rb
+++ b/app/controllers/application_controller/prevents_csrf.rb
@ -2,6 +2,9 @@ module ApplicationController::PreventsCsrf
  extend ActiveSupport::Concern

  included do
+    # disable Rails default (>= 5.2) CSRF checks
+    skip_before_action :verify_authenticity_token, raise: false
+
    before_action :verify_csrf_token
    after_action  :set_csrf_token_headers
  end
--- a/app/controllers/monitoring_controller.rb
+++ b/app/controllers/monitoring_controller.rb
@ -102,7 +102,7 @@ curl http://localhost/api/v1/monitoring/health_check?token=XXX
    handler_attempts_map = {}
    failed_jobs.order(:created_at).limit(10).each do |job|

-      job_name = if job.name == 'ActiveJob::QueueAdapters::DelayedJobAdapter::JobWrapper'.freeze
+      job_name = if job.class.name == 'Delayed::Backend::ActiveRecord::Job'.freeze && job.payload_object.respond_to?(:job_data)
                   job.payload_object.job_data['job_class']
                 else
                   job.name
--- a/app/jobs/application_job.rb
+++ b/app/jobs/application_job.rb
@ -9,12 +9,9 @@ class ApplicationJob < ActiveJob::Base
  # e.g. in the MonitoringController.
  # This is a workaround to sync ActiveJob#executions to Delayed::Job#attempts
  # until we resolve this dependency.
-  around_enqueue do |job, block|
-    block.call.tap do |delayed_job|
-      # skip test adapter
-      break if delayed_job.is_a?(Array)
-
-      delayed_job.update!(attempts: job.executions)
-    end
+  after_enqueue do |job|
+    # update the column right away without loading Delayed::Job record
+    # see: https://stackoverflow.com/a/34264580
+    Delayed::Job.where(id: job.provider_job_id).update_all(attempts: job.executions) # rubocop:disable Rails/SkipsModelValidations
  end
 end
--- a/app/models/activity_stream.rb
+++ b/app/models/activity_stream.rb
@ -5,8 +5,8 @@ class ActivityStream < ApplicationModel
  self.table_name = 'activity_streams'

  # rubocop:disable Rails/InverseOf
-  belongs_to :object, class_name: 'ObjectLookup', foreign_key: 'activity_stream_object_id'
-  belongs_to :type,   class_name: 'TypeLookup',   foreign_key: 'activity_stream_type_id'
+  belongs_to :object, class_name: 'ObjectLookup', foreign_key: 'activity_stream_object_id', optional: true
+  belongs_to :type,   class_name: 'TypeLookup',   foreign_key: 'activity_stream_type_id', optional: true
  # rubocop:enable Rails/InverseOf

  # the noop is needed since Layout/EmptyLines detects
--- a/app/models/application_model/can_associations.rb
+++ b/app/models/application_model/can_associations.rb
@ -134,7 +134,7 @@ returns
      next if association_attributes_ignored.include?(assoc_name)

      eager_load.push(assoc_name)
-      pluck.push("#{ActiveRecord::Base.connection.quote_table_name(assoc.table_name)}.id AS #{ActiveRecord::Base.connection.quote_table_name(assoc_name)}")
+      pluck.push(Arel.sql("#{ActiveRecord::Base.connection.quote_table_name(assoc.table_name)}.id AS #{ActiveRecord::Base.connection.quote_table_name(assoc_name)}"))
      keys.push("#{assoc_name.to_s.singularize}_ids")
    end

--- a/app/models/authorization.rb
+++ b/app/models/authorization.rb
@ -1,7 +1,7 @@
 # Copyright (C) 2012-2016 Zammad Foundation, http://zammad-foundation.org/

 class Authorization < ApplicationModel
-  belongs_to    :user
+  belongs_to    :user, optional: true
  after_create  :delete_user_cache
  after_update  :delete_user_cache
  after_destroy :delete_user_cache
--- a/app/models/avatar.rb
+++ b/app/models/avatar.rb
@ -1,7 +1,7 @@
 # Copyright (C) 2012-2016 Zammad Foundation, http://zammad-foundation.org/

 class Avatar < ApplicationModel
-  belongs_to :object_lookup
+  belongs_to :object_lookup, optional: true

 =begin

--- a/app/models/channel.rb
+++ b/app/models/channel.rb
@ -3,7 +3,7 @@
 class Channel < ApplicationModel
  include Channel::Assets

-  belongs_to :group
+  belongs_to :group, optional: true

  store :options
  store :preferences
--- a/app/models/concerns/can_be_published.rb
+++ b/app/models/concerns/can_be_published.rb
@ -31,7 +31,7 @@ module CanBePublished
      local  = "#{scope_name}_by".to_sym
      remote = inverse_relation_name(scope_name).to_sym

-      belongs_to local, class_name: 'User', inverse_of: remote
+      belongs_to local, class_name: 'User', inverse_of: remote, optional: true

      User.has_many remote, class_name: model_name, inverse_of: local, foreign_key: "#{local}_id"
      User.association_attributes_ignored remote
--- a/app/models/concerns/has_group_relation_definition.rb
+++ b/app/models/concerns/has_group_relation_definition.rb
@ -7,8 +7,8 @@ module HasGroupRelationDefinition
    self.table_name   = "groups_#{group_relation_model_identifier}s"
    self.primary_keys = ref_key, :group_id, :access

-    belongs_to group_relation_model_identifier
-    belongs_to :group
+    belongs_to group_relation_model_identifier, optional: true
+    belongs_to :group, optional: true

    validates :access, presence: true
    validate :validate_access
--- a/app/models/concerns/has_groups.rb
+++ b/app/models/concerns/has_groups.rb
@ -72,7 +72,7 @@ module HasGroups
    access   = self.class.ensure_group_access_list_parameter(access)

    # check direct access
-    return true if group_through.klass.includes(:group).exists?(
+    return true if group_through.klass.eager_load(:group).exists?(
      group_through.foreign_key => id,
      group_id: group_id,
      access: access,
@ -108,13 +108,13 @@ module HasGroups
    klass       = group_through.klass

    # check direct access
-    ids   = klass.includes(:group).where(foreign_key => id, access: access, groups: { active: true }).pluck(:group_id)
+    ids   = klass.eager_load(:group).where(foreign_key => id, access: access, groups: { active: true }).pluck(:group_id)
    ids ||= []

    # check indirect access through roles if possible
    return ids if !respond_to?(:role_ids)

-    role_group_ids = RoleGroup.includes(:group).where(role_id: role_ids, access: access, groups: { active: true }).pluck(:group_id)
+    role_group_ids = RoleGroup.eager_load(:group).where(role_id: role_ids, access: access, groups: { active: true }).pluck(:group_id)

    # combines and removes duplicates
    # and returns them in one statement
--- a/app/models/concerns/has_roles.rb
+++ b/app/models/concerns/has_roles.rb
@ -23,7 +23,7 @@ module HasRoles
    group_id = self.class.ensure_group_id_parameter(group_id)
    access   = self.class.ensure_group_access_list_parameter(access)

-    RoleGroup.includes(:group, :role).exists?(
+    RoleGroup.eager_load(:group, :role).exists?(
      role_id:  roles.pluck(:id),
      group_id: group_id,
      access:   access,
@ -58,7 +58,7 @@ module HasRoles
      group_id = ensure_group_id_parameter(group_id)
      access   = ensure_group_access_list_parameter(access)

-      role_ids   = RoleGroup.includes(:role).where(group_id: group_id, access: access, roles: { active: true }).pluck(:role_id)
+      role_ids   = RoleGroup.eager_load(:role).where(group_id: group_id, access: access, roles: { active: true }).pluck(:role_id)
      join_table = reflect_on_association(:roles).join_table
      joins(:roles).where(active: true, join_table => { role_id: role_ids }).distinct.select(&:groups_access_permission?)
    end
--- a/app/models/cti/caller_id.rb
+++ b/app/models/cti/caller_id.rb
@ -53,7 +53,7 @@ returns
          Cti::CallerId.select('MAX(id) as caller_id')
                       .where({ caller_id: caller_id, level: level }.compact)
                       .group(:user_id)
-                       .order('caller_id DESC') # not used as `caller_id: :desc` because is needed for `as caller_id`
+                       .order(Arel.sql('caller_id DESC')) # not used as `caller_id: :desc` because is needed for `as caller_id`
                       .limit(20)
                       .map(&:caller_id)
        end.find(&:present?)
--- a/app/models/email_address.rb
+++ b/app/models/email_address.rb
@ -4,7 +4,7 @@ class EmailAddress < ApplicationModel
  include ChecksLatestChangeObserved

  has_many        :groups,   after_add: :cache_update, after_remove: :cache_update
-  belongs_to      :channel
+  belongs_to      :channel, optional: true
  validates       :realname, presence: true
  validates       :email,    presence: true

--- a/app/models/group.rb
+++ b/app/models/group.rb
@ -8,8 +8,8 @@ class Group < ApplicationModel
  include HasHistory
  include HasObjectManagerAttributesValidation

-  belongs_to :email_address
-  belongs_to :signature
+  belongs_to :email_address, optional: true
+  belongs_to :signature, optional: true

  validates :name, presence: true

--- a/app/models/history.rb
+++ b/app/models/history.rb
@ -6,9 +6,9 @@ class History < ApplicationModel

  self.table_name = 'histories'

-  belongs_to :history_type,      class_name: 'History::Type'
-  belongs_to :history_object,    class_name: 'History::Object'
-  belongs_to :history_attribute, class_name: 'History::Attribute'
+  belongs_to :history_type,      class_name: 'History::Type', optional: true
+  belongs_to :history_object,    class_name: 'History::Object', optional: true
+  belongs_to :history_attribute, class_name: 'History::Attribute', optional: true

  # the noop is needed since Layout/EmptyLines detects
  # the block commend below wrongly as the measurement of
--- a/app/models/karma/activity_log.rb
+++ b/app/models/karma/activity_log.rb
@ -1,7 +1,7 @@
 # Copyright (C) 2012-2016 Zammad Foundation, http://zammad-foundation.org/

 class Karma::ActivityLog < ApplicationModel
-  belongs_to :object_lookup
+  belongs_to :object_lookup, optional: true

  self.table_name = 'karma_activity_logs'

--- a/app/models/knowledge_base/category.rb
+++ b/app/models/knowledge_base/category.rb
@ -22,7 +22,8 @@ class KnowledgeBase::Category < ApplicationModel
  belongs_to :parent,   class_name:  'KnowledgeBase::Category',
                        foreign_key: :parent_id,
                        inverse_of:  :children,
-                        touch:       true
+                        touch:       true,
+                        optional:    true

  validates :category_icon, presence: true

--- a/app/models/link.rb
+++ b/app/models/link.rb
@ -2,8 +2,8 @@

 class Link < ApplicationModel

-  belongs_to :link_type,   class_name: 'Link::Type'
-  belongs_to :link_object, class_name: 'Link::Object'
+  belongs_to :link_type,   class_name: 'Link::Type', optional: true
+  belongs_to :link_object, class_name: 'Link::Object', optional: true

  after_destroy :touch_link_references

--- a/app/models/object_manager/attribute.rb
+++ b/app/models/object_manager/attribute.rb
@ -22,7 +22,7 @@ class ObjectManager::Attribute < ApplicationModel

  self.table_name = 'object_manager_attributes'

-  belongs_to :object_lookup
+  belongs_to :object_lookup, optional: true

  validates :name, presence: true
  validates :data_type, inclusion: { in: DATA_TYPES, msg: '%{value} is not a valid data type' }
--- a/app/models/online_notification.rb
+++ b/app/models/online_notification.rb
@ -3,10 +3,10 @@
 class OnlineNotification < ApplicationModel
  include OnlineNotification::Assets

-  belongs_to :user
+  belongs_to :user, optional: true
  # rubocop:disable Rails/InverseOf
-  belongs_to :object, class_name: 'ObjectLookup', foreign_key: 'object_lookup_id'
-  belongs_to :type,   class_name: 'TypeLookup',   foreign_key: 'type_lookup_id'
+  belongs_to :object, class_name: 'ObjectLookup', foreign_key: 'object_lookup_id', optional: true
+  belongs_to :type,   class_name: 'TypeLookup',   foreign_key: 'type_lookup_id', optional: true
  # rubocop:enable Rails/InverseOf

  after_create    :notify_clients_after_change
--- a/app/models/organization/search.rb
+++ b/app/models/organization/search.rb
@ -104,7 +104,7 @@ returns
        # - stip out * we already search for *query* -
        query.delete! '*'
        organizations = Organization.where_or_cis(%i[name note], "%#{query}%")
-                                    .order(order_sql)
+                                    .order(Arel.sql(order_sql))
                                    .offset(offset)
                                    .limit(limit)
                                    .to_a
@ -118,7 +118,7 @@ returns
        organizations_by_user = Organization.select("DISTINCT(organizations.id), #{order_select_sql}")
                                            .joins('LEFT OUTER JOIN users ON users.organization_id = organizations.id')
                                            .where(User.or_cis(%i[firstname lastname email], "%#{query}%"))
-                                            .order(order_sql)
+                                            .order(Arel.sql(order_sql))
                                            .limit(limit)

        organizations_by_user.each do |organization_by_user|
--- a/app/models/recent_view.rb
+++ b/app/models/recent_view.rb
@ -4,8 +4,8 @@ class RecentView < ApplicationModel
  include RecentView::Assets

  # rubocop:disable Rails/InverseOf
-  belongs_to :ticket, foreign_key: 'o_id'
-  belongs_to :object, class_name: 'ObjectLookup', foreign_key: 'recent_view_object_id'
+  belongs_to :ticket, foreign_key: 'o_id', optional: true
+  belongs_to :object, class_name: 'ObjectLookup', foreign_key: 'recent_view_object_id', optional: true
  # rubocop:enable Rails/InverseOf

  after_create  :notify_clients
@ -42,7 +42,7 @@ class RecentView < ApplicationModel
                                     'MAX(id) as id')
                             .group(:o_id, :recent_view_object_id, :created_by_id)
                             .where(created_by_id: user.id)
-                             .order('MAX(created_at) DESC, MAX(id) DESC')
+                             .order(Arel.sql('MAX(created_at) DESC, MAX(id) DESC'))
                             .limit(limit)

    if object_name.present?
--- a/app/models/sla.rb
+++ b/app/models/sla.rb
@ -9,5 +9,5 @@ class Sla < ApplicationModel
  store      :condition
  store      :data
  validates  :name, presence: true
-  belongs_to :calendar
+  belongs_to :calendar, optional: true
 end
--- a/app/models/stats_store.rb
+++ b/app/models/stats_store.rb
@ -5,8 +5,8 @@ class StatsStore < ApplicationModel
  include StatsStore::SearchIndex

  # rubocop:disable Rails/InverseOf
-  belongs_to :stats_store_object, class_name: 'ObjectLookup', foreign_key: 'stats_store_object_id'
-  belongs_to :related_stats_store_object, class_name: 'ObjectLookup', foreign_key: 'related_stats_store_object_id'
+  belongs_to :stats_store_object, class_name: 'ObjectLookup', foreign_key: 'stats_store_object_id', optional: true
+  belongs_to :related_stats_store_object, class_name: 'ObjectLookup', foreign_key: 'related_stats_store_object_id', optional: true
  # rubocop:enable Rails/InverseOf

  store :data
--- a/app/models/store.rb
+++ b/app/models/store.rb
@ -5,8 +5,8 @@ require_dependency 'store/file'

 class Store < ApplicationModel

-  belongs_to :store_object, class_name: 'Store::Object'
-  belongs_to :store_file,   class_name: 'Store::File'
+  belongs_to :store_object, class_name: 'Store::Object', optional: true
+  belongs_to :store_file,   class_name: 'Store::File', optional: true

  validates :filename, presence: true

--- a/app/models/tag.rb
+++ b/app/models/tag.rb
@ -2,8 +2,8 @@

 class Tag < ApplicationModel

-  belongs_to :tag_object, class_name: 'Tag::Object'
-  belongs_to :tag_item,   class_name: 'Tag::Item'
+  belongs_to :tag_object, class_name: 'Tag::Object', optional: true
+  belongs_to :tag_item,   class_name: 'Tag::Item', optional: true

  # the noop is needed since Layout/EmptyLines detects
  # the block commend below wrongly as the measurement of
--- a/app/models/ticket.rb
+++ b/app/models/ticket.rb
@ -60,18 +60,18 @@ class Ticket < ApplicationModel

  sanitized_html :note

-  belongs_to    :group
-  belongs_to    :organization
+  belongs_to    :group, optional: true
+  belongs_to    :organization, optional: true
  has_many      :articles,               class_name: 'Ticket::Article', after_add: :cache_update, after_remove: :cache_update, dependent: :destroy, inverse_of: :ticket
  has_many      :ticket_time_accounting, class_name: 'Ticket::TimeAccounting', dependent: :destroy, inverse_of: :ticket
-  belongs_to    :state,                  class_name: 'Ticket::State'
-  belongs_to    :priority,               class_name: 'Ticket::Priority'
-  belongs_to    :owner,                  class_name: 'User'
-  belongs_to    :customer,               class_name: 'User'
-  belongs_to    :created_by,             class_name: 'User'
-  belongs_to    :updated_by,             class_name: 'User'
-  belongs_to    :create_article_type,    class_name: 'Ticket::Article::Type'
-  belongs_to    :create_article_sender,  class_name: 'Ticket::Article::Sender'
+  belongs_to    :state,                  class_name: 'Ticket::State', optional: true
+  belongs_to    :priority,               class_name: 'Ticket::Priority', optional: true
+  belongs_to    :owner,                  class_name: 'User', optional: true
+  belongs_to    :customer,               class_name: 'User', optional: true
+  belongs_to    :created_by,             class_name: 'User', optional: true
+  belongs_to    :updated_by,             class_name: 'User', optional: true
+  belongs_to    :create_article_type,    class_name: 'Ticket::Article::Type', optional: true
+  belongs_to    :create_article_sender,  class_name: 'Ticket::Article::Sender', optional: true

  self.inheritance_column = nil

@ -1001,7 +1001,7 @@ perform active triggers on ticket
    end

    triggers = if Rails.configuration.db_case_sensitive
-                 ::Trigger.where(active: true).order('LOWER(name)')
+                 ::Trigger.where(active: true).order(Arel.sql('LOWER(name)'))
               else
                 ::Trigger.where(active: true).order(:name)
               end
--- a/app/models/ticket/article.rb
+++ b/app/models/ticket/article.rb
@ -11,13 +11,13 @@ class Ticket::Article < ApplicationModel
  include Ticket::Article::ChecksAccess
  include Ticket::Article::Assets

-  belongs_to :ticket
+  belongs_to :ticket, optional: true
  has_one    :ticket_time_accounting, class_name: 'Ticket::TimeAccounting', foreign_key: :ticket_article_id, dependent: :destroy, inverse_of: :ticket_article
-  belongs_to :type,       class_name: 'Ticket::Article::Type'
-  belongs_to :sender,     class_name: 'Ticket::Article::Sender'
-  belongs_to :created_by, class_name: 'User'
-  belongs_to :updated_by, class_name: 'User'
-  belongs_to :origin_by,  class_name: 'User'
+  belongs_to :type,       class_name: 'Ticket::Article::Type', optional: true
+  belongs_to :sender,     class_name: 'Ticket::Article::Sender', optional: true
+  belongs_to :created_by, class_name: 'User', optional: true
+  belongs_to :updated_by, class_name: 'User', optional: true
+  belongs_to :origin_by,  class_name: 'User', optional: true

  before_create :check_subject, :check_body, :check_message_id_md5
  before_update :check_subject, :check_body, :check_message_id_md5
--- a/app/models/ticket/overviews.rb
+++ b/app/models/ticket/overviews.rb
@ -121,9 +121,9 @@ returns
                            .where(access_condition)
                            .where(query_condition, *bind_condition)
                            .joins(tables)
-                            .order("#{order_by} #{direction}")
+                            .order(Arel.sql("#{order_by} #{direction}"))
                            .limit(2000)
-                            .pluck(:id, :updated_at, order_by)
+                            .pluck(:id, :updated_at, Arel.sql(order_by))

      tickets = ticket_result.map do |ticket|
        {
--- a/app/models/ticket/search.rb
+++ b/app/models/ticket/search.rb
@ -190,7 +190,7 @@ returns
                            .where(access_condition)
                            .where('(tickets.title LIKE ? OR tickets.number LIKE ? OR ticket_articles.body LIKE ? OR ticket_articles.from LIKE ? OR ticket_articles.to LIKE ? OR ticket_articles.subject LIKE ?)', "%#{query}%", "%#{query}%", "%#{query}%", "%#{query}%", "%#{query}%", "%#{query}%" )
                            .joins(:articles)
-                            .order(order_sql)
+                            .order(Arel.sql(order_sql))
                            .offset(offset)
                            .limit(limit)
      else
@ -199,7 +199,7 @@ returns
                            .joins(tables)
                            .where(access_condition)
                            .where(query_condition, *bind_condition)
-                            .order(order_sql)
+                            .order(Arel.sql(order_sql))
                            .offset(offset)
                            .limit(limit)
      end
--- a/app/models/ticket/state.rb
+++ b/app/models/ticket/state.rb
@ -3,8 +3,8 @@ class Ticket::State < ApplicationModel
  include CanBeImported
  include ChecksLatestChangeObserved

-  belongs_to :state_type, class_name: 'Ticket::StateType', inverse_of: :states
-  belongs_to :next_state, class_name: 'Ticket::State'
+  belongs_to :state_type, class_name: 'Ticket::StateType', inverse_of: :states, optional: true
+  belongs_to :next_state, class_name: 'Ticket::State', optional: true

  after_create  :ensure_defaults
  after_update  :ensure_defaults
--- a/app/models/ticket/time_accounting.rb
+++ b/app/models/ticket/time_accounting.rb
@ -1,8 +1,8 @@
 # Copyright (C) 2012-2016 Zammad Foundation, http://zammad-foundation.org/
 class Ticket::TimeAccounting < ApplicationModel

-  belongs_to :ticket
-  belongs_to :ticket_article, class_name: 'Ticket::Article', inverse_of: :ticket_time_accounting
+  belongs_to :ticket, optional: true
+  belongs_to :ticket_article, class_name: 'Ticket::Article', inverse_of: :ticket_time_accounting, optional: true

  after_create :ticket_time_unit_update
  after_update :ticket_time_unit_update
--- a/app/models/token.rb
+++ b/app/models/token.rb
@ -2,7 +2,7 @@

 class Token < ActiveRecord::Base
  before_create :generate_token
-  belongs_to    :user
+  belongs_to    :user, optional: true
  store         :preferences

 =begin
--- a/app/models/user.rb
+++ b/app/models/user.rb
@ -1,4 +1,6 @@
 # Copyright (C) 2012-2016 Zammad Foundation, http://zammad-foundation.org/
+require_dependency 'karma/user'
+
 class User < ApplicationModel
  include CanBeImported
  include HasActivityStreamLog
@ -20,7 +22,7 @@ class User < ApplicationModel
  has_and_belongs_to_many :organizations,  after_add: :cache_update, after_remove: :cache_update, class_name: 'Organization'
  has_many                :tokens,         after_add: :cache_update, after_remove: :cache_update
  has_many                :authorizations, after_add: :cache_update, after_remove: :cache_update
-  belongs_to              :organization,   inverse_of: :members
+  belongs_to              :organization,   inverse_of: :members, optional: true

  before_validation :check_name, :check_email, :check_login, :ensure_uniq_email, :ensure_password, :ensure_roles, :ensure_identifier
  before_validation :check_mail_delivery_failed, on: :update
--- a/app/models/user/search.rb
+++ b/app/models/user/search.rb
@ -137,11 +137,17 @@ returns
        users = if params[:role_ids]
                  User.joins(:roles).where('roles.id' => params[:role_ids]).where(
                    '(users.firstname LIKE ? OR users.lastname LIKE ? OR users.email LIKE ? OR users.login LIKE ?) AND users.id != 1', "%#{query}%", "%#{query}%", "%#{query}%", "%#{query}%"
-                  ).order(order_sql).offset(offset).limit(limit)
+                  )
+                  .order(Arel.sql(order_sql))
+                  .offset(offset)
+                  .limit(limit)
                else
                  User.where(
                    '(firstname LIKE ? OR lastname LIKE ? OR email LIKE ? OR login LIKE ?) AND id != 1', "%#{query}%", "%#{query}%", "%#{query}%", "%#{query}%"
-                  ).order(order_sql).offset(offset).limit(limit)
+                  )
+                  .order(Arel.sql(order_sql))
+                  .offset(offset)
+                  .limit(limit)
                end
        users
      end
--- a/bin/rails
+++ b/bin/rails
@ -4,6 +4,6 @@ begin
 rescue LoadError => e
  raise unless e.message.include?('spring')
 end
-APP_PATH = File.expand_path('../../config/application', __FILE__)
+APP_PATH = File.expand_path('../config/application', __dir__)
 require_relative '../config/boot'
 require 'rails/commands'
--- a/bin/setup
+++ b/bin/setup
@ -1,29 +1,36 @@
 #!/usr/bin/env ruby
-require 'pathname'
+require 'fileutils'
+include FileUtils # rubocop:disable Style/MixinUsage

 # path to your application root.
-APP_ROOT = Pathname.new File.expand_path('..',  __dir__)
+APP_ROOT = File.expand_path('..', __dir__)

-Dir.chdir APP_ROOT do
+def system!(*args)
+  system(*args) || abort("\n== Command #{args} failed ==")
+end
+
+chdir APP_ROOT do
  # This script is a starting point to setup your application.
-  # Add necessary setup steps to this file:
+  # Add necessary setup steps to this file.

  puts '== Installing dependencies =='
-  system 'gem install bundler --conservative'
-  system 'bundle check || bundle install --jobs 8'
+  system! 'gem install bundler --conservative'
+  system('bundle check') || system!('bundle install')
+
+  # Install JavaScript dependencies if using Yarn
+  # system('bin/yarn')

  # puts "\n== Copying sample files =="
-  # unless File.exist?("config/database.yml")
-  #   system "cp config/database.yml.sample config/database.yml"
+  # unless File.exist?('config/database.yml')
+  #   cp 'config/database.yml.sample', 'config/database.yml'
  # end

  puts "\n== Preparing database =="
-  system 'bin/rake db:setup'
+  system! 'bin/rails db:setup'

  puts "\n== Removing old logs and tempfiles =="
-  system 'rm -f log/*'
-  system 'rm -rf tmp/cache'
+  system! 'bin/rails log:clear tmp:clear'

  puts "\n== Restarting application server =="
-  system 'touch tmp/restart.txt'
+  system! 'bin/rails restart'
 end
--- a/bin/update
+++ b/bin/update
@ -0,0 +1,31 @@
+#!/usr/bin/env ruby
+require 'fileutils'
+include FileUtils # rubocop:disable Style/MixinUsage
+
+# path to your application root.
+APP_ROOT = File.expand_path('..', __dir__)
+
+def system!(*args)
+  system(*args) || abort("\n== Command #{args} failed ==")
+end
+
+chdir APP_ROOT do
+  # This script is a way to update your development environment automatically.
+  # Add necessary update steps to this file.
+
+  puts '== Installing dependencies =='
+  system! 'gem install bundler --conservative'
+  system('bundle check') || system!('bundle install')
+
+  # Install JavaScript dependencies if using Yarn
+  # system('bin/yarn')
+
+  puts "\n== Updating database =="
+  system! 'bin/rails db:migrate'
+
+  puts "\n== Removing old logs and tempfiles =="
+  system! 'bin/rails log:clear tmp:clear'
+
+  puts "\n== Restarting application server =="
+  system! 'bin/rails restart'
+end
--- a/bin/yarn
+++ b/bin/yarn
@ -0,0 +1,9 @@
+#!/usr/bin/env ruby
+APP_ROOT = File.expand_path('..', __dir__)
+Dir.chdir(APP_ROOT) do
+  exec 'yarnpkg', *ARGV
+rescue Errno::ENOENT
+  warn 'Yarn executable was not detected in the system.'
+  warn 'Download Yarn at https://yarnpkg.com/en/docs/install'
+  exit 1
+end
--- a/config/application.rb
+++ b/config/application.rb
@ -1,4 +1,4 @@
-require File.expand_path('boot', __dir__)
+require_relative 'boot'

 require 'rails/all'

@ -11,6 +11,9 @@ Bundler.require(*Rails.groups)

 module Zammad
  class Application < Rails::Application
+    # Initialize configuration defaults for originally generated Rails version.
+    config.load_defaults 5.2
+
    # Settings in config/environments/* take precedence over those specified here.
    # Application configuration should go into files in config/initializers
    # -- all .rb files in that directory are automatically loaded.
--- a/config/boot.rb
+++ b/config/boot.rb
@ -1,3 +1,4 @@
 ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../Gemfile', __dir__)

 require 'bundler/setup' # Set up gems listed in the Gemfile.
+require 'bootsnap/setup' # Speed up boot time by caching expensive operations.
--- a/config/environment.rb
+++ b/config/environment.rb
@ -1,5 +1,5 @@
 # Load the Rails application.
-require File.expand_path('application', __dir__)
+require_relative 'application'

 # Initialize the Rails application.
 Rails.application.initialize!
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@ -9,28 +9,68 @@ Rails.application.configure do
  # Do not eager load code on boot.
  config.eager_load = false

-  # Show full error reports and disable caching.
-  config.consider_all_requests_local       = true
-  config.action_controller.perform_caching = false
+  # Show full error reports.
+  config.consider_all_requests_local = true
+
+  # Enable/disable caching. By default caching is disabled.
+  # Run rails dev:cache to toggle caching.
+  if Rails.root.join('tmp', 'caching-dev.txt').exist?
+    config.action_controller.perform_caching = true
+
+    config.cache_store = :memory_store
+    config.public_file_server.headers = {
+      'Cache-Control' => "public, max-age=#{2.days.to_i}"
+    }
+  else
+    config.action_controller.perform_caching = false
+
+    config.cache_store = :null_store
+  end
+
+  # Store uploaded files on the local file system (see config/storage.yml for options)
+  # config.active_storage.service = :local

  # Don't care if the mailer can't send.
  config.action_mailer.raise_delivery_errors = false

+  config.action_mailer.perform_caching = false
+
  # Print deprecation notices to the Rails logger.
  config.active_support.deprecation = :log

  # Raise an error on page load if there are pending migrations.
  config.active_record.migration_error = :page_load

-  # Do not compress assets
-  config.assets.compress = false
+  # Highlight code that triggered database queries in logs.
+  config.active_record.verbose_query_logs = true

  # Debug mode disables concatenation and preprocessing of assets.
  # This option may cause significant delays in view rendering with a large
  # number of complex assets.
-  #config.assets.debug = true
  config.assets.debug = false

+  # Suppress logger output for asset requests.
+  config.assets.quiet = true
+
+  # Raises error for missing translations
+  # config.action_view.raise_on_missing_translations = true
+
+  # Use an evented file watcher to asynchronously detect changes in source code,
+  # routes, locales, etc. This feature depends on the listen gem.
+  config.file_watcher = ActiveSupport::EventedFileUpdateChecker
+
+  # Asset digests allow you to set far-future HTTP expiration dates on all assets,
+  # yet still be able to expire them through the digest params.
+  config.assets.digest = false
+
+  # Adds additional error checking when serving assets at runtime.
+  # Checks for improperly declared sprockets dependencies.
+  # Raises helpful error messages.
+  config.assets.raise_runtime_errors = true
+
+  # Raises error for missing translations
+  # config.action_view.raise_on_missing_translations = true
+
  # Automatically inject JavaScript needed for LiveReload
  if ENV['RAKE_LIVE_RELOAD'].present?
    require 'rack-livereload'
@ -43,16 +83,4 @@ Rails.application.configure do
      live_reload_port: 35_738
    )
  end
-
-  # Asset digests allow you to set far-future HTTP expiration dates on all assets,
-  # yet still be able to expire them through the digest params.
-  config.assets.digest = false
-
-  # Adds additional error checking when serving assets at runtime.
-  # Checks for improperly declared sprockets dependencies.
-  # Raises helpful error messages.
-  config.assets.raise_runtime_errors = true
-
-  # Raises error for missing translations
-  # config.action_view.raise_on_missing_translations = true
 end
--- a/config/environments/production.rb
+++ b/config/environments/production.rb
@ -14,11 +14,9 @@ Rails.application.configure do
  config.consider_all_requests_local       = false
  config.action_controller.perform_caching = true

-  # Enable Rack::Cache to put a simple HTTP cache in front of your application
-  # Add `rack-cache` to your Gemfile before enabling this.
-  # For large-scale production use, consider using a caching reverse proxy like
-  # NGINX, varnish or squid.
-  # config.action_dispatch.rack_cache = true
+  # Ensures that a master key has been made available in either ENV["RAILS_MASTER_KEY"]
+  # or in config/master.key. This key is used to decrypt credentials (and other encrypted files).
+  # config.require_master_key = true

  # Disable serving static files from the `/public` folder by default since
  # Apache or NGINX already handles this.
@ -31,16 +29,23 @@ Rails.application.configure do
  # Do not fallback to assets pipeline if a precompiled asset is missed.
  config.assets.compile = false

-  # Asset digests allow you to set far-future HTTP expiration dates on all assets,
-  # yet still be able to expire them through the digest params.
-  config.assets.digest = true
-
  # `config.assets.precompile` and `config.assets.version` have moved to config/initializers/assets.rb

+  # Enable serving of images, stylesheets, and JavaScripts from an asset server.
+  # config.action_controller.asset_host = 'http://assets.example.com'
+
  # Specifies the header that your server uses for sending files.
  # config.action_dispatch.x_sendfile_header = 'X-Sendfile' # for Apache
  # config.action_dispatch.x_sendfile_header = 'X-Accel-Redirect' # for NGINX

+  # Store uploaded files on the local file system (see config/storage.yml for options)
+  # config.active_storage.service = :local
+
+  # Mount Action Cable outside main process or domain
+  # config.action_cable.mount_path = nil
+  # config.action_cable.url = 'wss://example.com/cable'
+  # config.action_cable.allowed_request_origins = [ 'http://example.com', /http:\/\/example.*/ ]
+
  # Force all access to the app over SSL, use Strict-Transport-Security, and use secure cookies.
  # config.force_ssl = true

@ -49,19 +54,16 @@ Rails.application.configure do
  config.log_level = :info

  # Prepend all log lines with the following tags.
-  # config.log_tags = [ :subdomain, :uuid ]
+  config.log_tags = [ :request_id ]

-  # Use a different logger for distributed setups.
-  # config.logger = ActiveSupport::TaggedLogging.new(SyslogLogger.new)
+  # Use a different cache store in production.
+  # config.cache_store = :mem_cache_store

-  if ENV['RAILS_LOG_TO_STDOUT'].present?
-    logger           = ActiveSupport::Logger.new(STDOUT)
-    logger.formatter = config.log_formatter
-    config.logger    = ActiveSupport::TaggedLogging.new(logger)
-  end
+  # Use a real queuing backend for Active Job (and separate queues per environment)
+  # config.active_job.queue_adapter     = :resque
+  # config.active_job.queue_name_prefix = "zammad_#{Rails.env}"

-  # Enable serving of images, stylesheets, and JavaScripts from an asset server.
-  # config.action_controller.asset_host = 'http://assets.example.com'
+  config.action_mailer.perform_caching = false

  # Ignore bad email addresses and do not raise email delivery errors.
  # Set this to true and configure the email server for immediate delivery to raise delivery errors.
@ -77,6 +79,19 @@ Rails.application.configure do
  # Send deprecation notices to registered listeners.
  config.active_support.deprecation = :notify

+  # Use default logging formatter so that PID and timestamp are not suppressed.
+  # config.log_formatter = ::Logger::Formatter.new
+
+  # Use a different logger for distributed setups.
+  # require 'syslog/logger'
+  # config.logger = ActiveSupport::TaggedLogging.new(Syslog::Logger.new 'app-name')
+
+  if ENV['RAILS_LOG_TO_STDOUT'].present?
+    logger           = ActiveSupport::Logger.new(STDOUT)
+    logger.formatter = config.log_formatter
+    config.logger    = ActiveSupport::TaggedLogging.new(logger)
+  end
+
  # Do not dump schema after migrations.
  config.active_record.dump_schema_after_migration = false

--- a/config/environments/test.rb
+++ b/config/environments/test.rb
@ -12,9 +12,11 @@ Rails.application.configure do
  # preloads Rails for running tests, you may have to set it to true.
  config.eager_load = false

-  # Configure static file server for tests with Cache-Control for performance.
+  # Configure public file server for tests with Cache-Control for performance.
  config.public_file_server.enabled = true
-  config.public_file_server.headers = { 'Cache-Control' => 'public, max-age=3600' }
+  config.public_file_server.headers = {
+    'Cache-Control' => "public, max-age=#{1.hour.to_i}"
+  }

  # Show full error reports and disable caching.
  config.consider_all_requests_local       = true
@ -26,6 +28,11 @@ Rails.application.configure do
  # Disable request forgery protection in test environment.
  config.action_controller.allow_forgery_protection = false

+  # Store uploaded files on the local file system in a temporary directory
+  # config.active_storage.service = :test
+
+  config.action_mailer.perform_caching = false
+
  # Tell Action Mailer not to deliver emails to the real world.
  # The :test delivery method accumulates sent emails in the
  # ActionMailer::Base.deliveries array.
@ -43,6 +50,7 @@ Rails.application.configure do
  # Enable autoload
  config.dependency_loading = true

+  # Reduce log level to speed up test runs.
  config.after_initialize do
    ActiveRecord::Base.logger = Rails.logger.clone
    ActiveRecord::Base.logger.level = Logger::INFO
--- a/config/initializers/application_controller_renderer.rb
+++ b/config/initializers/application_controller_renderer.rb
@ -0,0 +1,8 @@
+# Be sure to restart your server when you modify this file.
+
+# ActiveSupport::Reloader.to_prepare do
+#   ApplicationController.renderer.defaults.merge!(
+#     http_host: 'example.org',
+#     https: false
+#   )
+# end
--- a/config/initializers/assets.rb
+++ b/config/initializers/assets.rb
@ -3,11 +3,15 @@
 # Version of your assets, change this if you want to expire all your assets.
 Rails.application.config.assets.version = '1.0'

-# Add additional assets to the asset load path
+# Add additional assets to the asset load path.
 # Rails.application.config.assets.paths << Emoji.images_path
+# Add Yarn node_modules folder to the asset load path.
+# Rails.application.config.assets.paths << Rails.root.join('node_modules')

 # Precompile additional assets.
-# application.js, application.css, and all non-JS/CSS in app/assets folder are already added.
+# application.js, application.css, and all non-JS/CSS in the app/assets
+# folder are already added.
+# Rails.application.config.assets.precompile += %w( admin.js admin.css )
 Rails.application.config.assets.precompile += %w[application-print.css]
 Rails.application.config.assets.precompile += %w[print.css]
 Rails.application.config.assets.precompile += %w[knowledge_base.css knowledge_base_public.js knowledge_base_public_polyfills.js]
--- a/config/initializers/content_security_policy.rb
+++ b/config/initializers/content_security_policy.rb
@ -0,0 +1,25 @@
+# Be sure to restart your server when you modify this file.
+
+# Define an application-wide content security policy
+# For further information see the following documentation
+# https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy
+
+# Rails.application.config.content_security_policy do |policy|
+#   policy.default_src :self, :https
+#   policy.font_src    :self, :https, :data
+#   policy.img_src     :self, :https, :data
+#   policy.object_src  :none
+#   policy.script_src  :self, :https
+#   policy.style_src   :self, :https
+
+#   # Specify URI for violation reports
+#   # policy.report_uri "/csp-violation-report-endpoint"
+# end
+
+# If you are using UJS then enable automatic nonce generation
+# Rails.application.config.content_security_policy_nonce_generator = -> request { SecureRandom.base64(16) }
+
+# Report CSP violations to a specified URI
+# For further information see the following documentation:
+# https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy-Report-Only
+# Rails.application.config.content_security_policy_report_only = true
--- a/config/initializers/cookies_serializer.rb
+++ b/config/initializers/cookies_serializer.rb
@ -1,3 +1,5 @@
 # Be sure to restart your server when you modify this file.

+# Specify a serializer for the signed and encrypted cookie jars.
+# Valid options are :json, :marshal, and :hybrid.
 Rails.application.config.action_dispatch.cookies_serializer = :marshal
--- a/config/initializers/db_preferences.rb
+++ b/config/initializers/db_preferences.rb
@ -1,6 +1,12 @@
-# set database preferences
-
-# defaults
-Rails.application.config.db_case_sensitive = false
-Rails.application.config.db_like = 'LIKE'
-Rails.application.config.db_4bytes_utf8 = true
+case ActiveRecord::Base.connection_config[:adapter]
+when 'mysql2'
+  Rails.application.config.db_4bytes_utf8 = false
+  Rails.application.config.db_case_sensitive = false
+  Rails.application.config.db_like = 'LIKE'
+  Rails.application.config.db_null_byte = true
+when 'postgresql'
+  Rails.application.config.db_4bytes_utf8 = true
+  Rails.application.config.db_case_sensitive = true
+  Rails.application.config.db_like = 'ILIKE'
+  Rails.application.config.db_null_byte = false
+end
--- a/config/initializers/db_preferences_mysql.rb
+++ b/config/initializers/db_preferences_mysql.rb
@ -1,78 +0,0 @@
-return if ActiveRecord::Base.connection_config[:adapter] != 'mysql2'
-
-Rails.application.config.db_4bytes_utf8 = false
-Rails.application.config.db_null_byte = true
-connection = ActiveRecord::Base.connection
-
-# rubocop:disable Rails/Output
-# rubocop:disable Rails/Exit
-# rubocop:disable Layout/IndentHeredoc
-
-# Version check --------------------------------------------------------------
-#  mysql example: "5.7.3"
-#  mariadb example: "10.1.17-MariaDB"
-server_version = connection.execute('SELECT @@version;').first.first
-raise 'Unable to retrive database version' if server_version.blank?
-
-version_number = Gem::Version.new(server_version.split('-').first)
-vendor         = server_version.split('-').second || 'MySQL'
-
-case vendor
-when 'MySQL'
-  if version_number < Gem::Version.new('5.6')
-    printf "\e[31m" # ANSI red
-    puts <<~MSG
-    Error: Incompatible database backend version
-    (MySQL 5.6+ required; #{version_number} found)
-    MSG
-    printf "\e[0m" # ANSI normal
-    exit 1
-  end
-when 'MariaDB'
-  if version_number < Gem::Version.new('10.0')
-    printf "\e[31m" # ANSI red
-    puts <<~MSG
-    Error: Incompatible database backend version
-    (MariaDB 10.0+ required; #{version_number} found)
-    MSG
-    printf "\e[0m" # ANSI normal
-    exit 1
-  end
-end
-
-# Configuration check --------------------------------------------------------
-# Before MySQL 8.0, the default value of max_allowed_packet was 1MB - 4MB,
-# which is impractically small and can lead to failures processing emails.
-#
-# See https://github.com/zammad/zammad/issues/1759
-#     https://github.com/zammad/zammad/issues/1970
-#     https://github.com/zammad/zammad/issues/2034
-max_allowed_packet = connection.execute('SELECT @@max_allowed_packet;').first.first
-max_allowed_packet_mb = max_allowed_packet / 1024 / 1024
-
-if max_allowed_packet_mb <= 4
-  printf "\e[31m" # ANSI red
-  puts <<~MSG
-  Error: Database config value 'max_allowed_packet' too small (#{max_allowed_packet_mb}MB)
-  Please increase this value in your #{vendor} configuration (64MB+ recommended).
-  MSG
-  printf "\e[0m" # ANSI normal
-  exit 1
-end
-
-if connection.execute("SHOW tables LIKE 'settings';").any? &&
-   Setting.get('postmaster_max_size').present? &&
-   Setting.get('postmaster_max_size').to_i > max_allowed_packet_mb
-  printf "\e[33m" # ANSI yellow
-  puts <<~MSG
-  Warning: Database config value 'max_allowed_packet' less than Zammad setting 'Maximum Email Size'
-  Zammad will fail to process emails (both incoming and outgoing)
-  larger than the value of 'max_allowed_packet' (#{max_allowed_packet_mb}MB).
-  Please increase this value in your #{vendor} configuration accordingly.
-  MSG
-  printf "\e[0m" # ANSI normal
-end
-
-# rubocop:enable Rails/Exit
-# rubocop:enable Rails/Output
-# rubocop:enable Layout/IndentHeredoc
--- a/config/initializers/db_preferences_postgresql.rb
+++ b/config/initializers/db_preferences_postgresql.rb
@ -1,29 +0,0 @@
-return if ActiveRecord::Base.connection_config[:adapter] != 'postgresql'
-
-Rails.application.config.db_case_sensitive = true
-Rails.application.config.db_like = 'ILIKE'
-Rails.application.config.db_null_byte = false
-
-# rubocop:disable Rails/Output
-# rubocop:disable Rails/Exit
-# rubocop:disable Layout/IndentHeredoc
-
-# Version check --------------------------------------------------------------
-#  example output: "9.5.0"
-#                  "10.3 (Debian 10.3-2)"
-server_version = ActiveRecord::Base.connection.execute('SHOW server_version;').first['server_version']
-version_number = Gem::Version.new(server_version.split.first)
-
-if version_number < Gem::Version.new('9.1')
-  printf "\e[31m" # ANSI red
-  puts <<~MSG
-  Error: Incompatible database backend version
-  (PostgreSQL 9.1+ required; #{version_number} found)
-  MSG
-  printf "\e[0m" # ANSI normal
-  exit 1
-end
-
-# rubocop:enable Rails/Exit
-# rubocop:enable Rails/Output
-# rubocop:enable Layout/IndentHeredoc
--- a/config/initializers/db_preflight_check.rb
+++ b/config/initializers/db_preflight_check.rb
@ -0,0 +1,4 @@
+# Rails' constant auto-loading resolves to 'rails/initializable' instead
+require_dependency 'zammad/application/initializer/db_preflight_check'
+
+Zammad::Application::Initializer::DBPreflightCheck.perform
--- a/config/initializers/logo.rb
+++ b/config/initializers/logo.rb
@ -1,6 +1,7 @@
+return if !ActiveRecord::Base.connected?
+
 # sync logo to fs / only if settings already exists
-if ActiveRecord::Base.connection.tables.include?('settings')
-  if Setting.column_names.include?('state_current')
-    StaticAssets.sync
-  end
-end
+return if ActiveRecord::Base.connection.tables.exclude?('settings')
+return if Setting.column_names.exclude?('state_current')
+
+StaticAssets.sync
--- a/config/initializers/models_searchable.rb
+++ b/config/initializers/models_searchable.rb
@ -1,11 +1,9 @@
 # update settings for searchable models
-if ActiveRecord::Base.connection.tables.include?('settings')
-  if Setting.columns_hash.key?('state_current') # TODO: remove me later
-    models_current = Models.searchable.map(&:to_s)
-    models_config = Setting.get('models_searchable')
-    setting = Setting.find_by(name: 'models_searchable')
-    if setting && models_current != models_config
-      Setting.set('models_searchable', models_current)
-    end
-  end
+
+begin
+  return if !Setting.exists?(name: 'models_searchable')
+
+  Setting.set('models_searchable', Models.searchable.map(&:to_s))
+rescue ActiveRecord::StatementInvalid
+  nil
 end
--- a/config/initializers/wrap_parameters.rb
+++ b/config/initializers/wrap_parameters.rb
@ -10,5 +10,5 @@ end

 # To enable root element in JSON for ActiveRecord objects.
 # ActiveSupport.on_load(:active_record) do
-#  self.include_root_in_json = true
+#   self.include_root_in_json = true
 # end
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@ -1,5 +1,33 @@
-# Sample localization file for English. Add more files in this directory for other locales.
-# See https://github.com/svenfuchs/rails-i18n/tree/master/rails%2Flocale for starting points.
+# Files in the config/locales directory are used for internationalization
+# and are automatically loaded by Rails. If you want to use locales other
+# than English, add the necessary files in this directory.
+#
+# To use the locales, use `I18n.t`:
+#
+#     I18n.t 'hello'
+#
+# In views, this is aliased to just `t`:
+#
+#     <%= t('hello') %>
+#
+# To use a different locale, set it with `I18n.locale`:
+#
+#     I18n.locale = :es
+#
+# This would use the information in config/locales/es.yml.
+#
+# The following keys must be escaped otherwise they will not be retrieved by
+# the default I18n backend:
+#
+# true, false, on, off, yes, no
+#
+# Instead, surround them with single quotes.
+#
+# en:
+#   'true': 'foo'
+#
+# To learn more, please read the Rails Internationalization guide
+# available at http://guides.rubyonrails.org/i18n.html.

 en:
  hello: "Hello world"
--- a/config/spring.rb
+++ b/config/spring.rb
@ -1,3 +1,10 @@
+%w[
+  .ruby-version
+  .rbenv-vars
+  tmp/restart.txt
+  tmp/caching-dev.txt
+].each { |path| Spring.watch(path) }
+
 module Spring
  module Commands
    class SchedulerRb
--- a/lib/zammad/application/initializer/db_preflight_check.rb
+++ b/lib/zammad/application/initializer/db_preflight_check.rb
@ -0,0 +1,19 @@
+require 'zammad/application/initializer/db_preflight_check/base'
+require 'zammad/application/initializer/db_preflight_check/mysql2'
+require 'zammad/application/initializer/db_preflight_check/postgresql'
+
+module Zammad
+  class Application
+    class Initializer
+      module DBPreflightCheck
+        def self.perform
+          adapter.perform
+        end
+
+        def self.adapter
+          @adapter ||= const_get(ActiveRecord::Base.connection_config[:adapter].capitalize)
+        end
+      end
+    end
+  end
+end
--- a/lib/zammad/application/initializer/db_preflight_check/base.rb
+++ b/lib/zammad/application/initializer/db_preflight_check/base.rb
@ -0,0 +1,43 @@
+# NOTE: Why use Mysql2::Client / PG::Connection over ActiveRecord::Base.connection?
+#
+# As of Rails 5.2, db:create now runs initializers prior to creating the DB.
+# That means if an initializer tries to establish an ActiveRecord::Base.connection,
+# it will raise an ActiveRecord::NoDatabaseError
+# (see https://github.com/rails/rails/issues/32870 for more details).
+#
+# The workaround is to use the bare RDBMS library
+# and connect without specifying a database (MySQL),
+# or connect to a standard system database instead (PostgreSQL).
+
+module Zammad
+  class Application
+    class Initializer
+      module DBPreflightCheck
+        module Base
+          def check_version_compatibility
+            return if Gem::Version.new(current_version) >= Gem::Version.new(min_version)
+
+            err(<<~MSG)
+              Incompatible database backend version
+              (#{vendor} #{min_version}+ required; #{current_version} found)
+            MSG
+          end
+
+          def warn(msg)
+            printf "\e[33m" # ANSI yellow
+            puts "Warning: #{msg}" # rubocop:disable Rails/Output
+            printf "\e[0m" # ANSI normal
+          end
+
+          def err(msg)
+            printf "\e[31m" # ANSI red
+            puts "Error: #{msg}" # rubocop:disable Rails/Output
+            printf "\e[0m" # ANSI normal
+
+            exit 1 # rubocop:disable Rails/Exit
+          end
+        end
+      end
+    end
+  end
+end
--- a/lib/zammad/application/initializer/db_preflight_check/mysql2.rb
+++ b/lib/zammad/application/initializer/db_preflight_check/mysql2.rb
@ -0,0 +1,88 @@
+# NOTE: Why use Mysql2::Client over ActiveRecord::Base.connection?
+#
+# As of Rails 5.2, db:create now runs initializers prior to creating the DB.
+# That means if an initializer tries to establish an ActiveRecord::Base.connection,
+# it will raise an ActiveRecord::NoDatabaseError
+# (see https://github.com/rails/rails/issues/32870 for more details).
+#
+# The workaround is to use the bare RDBMS library
+# and connect without specifying a database.
+
+module Zammad
+  class Application
+    class Initializer
+      module DBPreflightCheck
+        module Mysql2
+          extend Base
+
+          def self.perform
+            check_version_compatibility
+            check_max_allowed_packet
+          end
+
+          # Configuration check --------------------------------------------------
+          # Before MySQL 8.0, the default value of max_allowed_packet was 1MB - 4MB,
+          # which is impractically small and can lead to email processing failures.
+          #
+          # See https://github.com/zammad/zammad/issues/1759
+          #     https://github.com/zammad/zammad/issues/1970
+          #     https://github.com/zammad/zammad/issues/2034
+          def self.check_max_allowed_packet
+            if max_allowed_packet_mb <= 4
+              err(<<~MSG)
+                Database config value 'max_allowed_packet' too small (#{max_allowed_packet_mb}MB)
+                Please increase this value in your #{vendor} configuration (64MB+ recommended).
+              MSG
+            elsif max_allowed_packet_mb < Setting.get('postmaster_max_size').to_i
+              warn(<<~MSG)
+                Database config value 'max_allowed_packet' less than Zammad setting 'Maximum Email Size'
+                Zammad will fail to process emails (both incoming and outgoing)
+                larger than the value of 'max_allowed_packet' (#{max_allowed_packet_mb}MB).
+                Please increase this value in your #{vendor} configuration accordingly.
+              MSG
+            end
+          # Setting.get will fail if 'settings' table does not exist
+          rescue ActiveRecord::StatementInvalid # rubocop:disable Lint/HandleExceptions
+          end
+
+          def self.connection
+            @connection ||= ::Mysql2::Client.new(db_config)
+          end
+
+          def self.db_config
+            @db_config ||= ActiveRecord::Base.connection_config
+                                             .symbolize_keys
+                                             .except(:database)
+          end
+
+          #  formats: "5.7.3" (MySQL)
+          #           "10.1.17-MariaDB" (MariaDB)
+          def self.current_version
+            @current_version ||= mysql_variable('version').split('-').first
+          end
+
+          def self.min_version
+            case vendor
+            when 'MySQL'
+              '5.6'
+            when 'MariaDB'
+              '10.0'
+            end
+          end
+
+          def self.vendor
+            @vendor ||= mysql_variable('version').split('-').second || 'MySQL'
+          end
+
+          def self.max_allowed_packet_mb
+            @max_allowed_packet_mb ||= mysql_variable('max_allowed_packet') / 1024 / 1024
+          end
+
+          def self.mysql_variable(name)
+            connection.query("SELECT @@#{name};").first["@@#{name}"]
+          end
+        end
+      end
+    end
+  end
+end
--- a/lib/zammad/application/initializer/db_preflight_check/postgresql.rb
+++ b/lib/zammad/application/initializer/db_preflight_check/postgresql.rb
@ -0,0 +1,73 @@
+# NOTE: Why use PG::Connection over ActiveRecord::Base.connection?
+#
+# As of Rails 5.2, db:create now runs initializers prior to creating the DB.
+# That means if an initializer tries to establish an ActiveRecord::Base.connection,
+# it will raise an ActiveRecord::NoDatabaseError
+# (see https://github.com/rails/rails/issues/32870 for more details).
+#
+# The workaround is to use the bare RDBMS library
+# and connect to a standard system database instead.
+
+module Zammad
+  class Application
+    class Initializer
+      module DBPreflightCheck
+        module Postgresql
+          extend Base
+
+          def self.perform
+            check_version_compatibility
+          ensure
+            connection.try(:finish)
+          end
+
+          def self.check_version_compatibility
+            return if connection.nil?  # Edge case: if Postgres can't find a DB to connect to
+
+            super
+          end
+
+          def self.connection
+            alternate_dbs = %w[template0 template1 postgres]
+
+            @connection ||= begin
+                              PG.connect(db_config)
+                            rescue PG::ConnectionBad
+                              db_config[:dbname] = alternate_dbs.pop
+                              retry if db_config[:dbname].present?
+                            end
+          end
+
+          # Adapted from ActiveRecord::ConnectionHandling#postgresql_connection
+          def self.db_config
+            @db_config ||= ActiveRecord::Base.connection_config.dup.tap do |config|
+              config.symbolize_keys!
+              config[:user] = config.delete(:username)
+              config[:dbname] = config.delete(:database)
+              config.slice!(*PG::Connection.conndefaults_hash.keys, :requiressl)
+              config.compact!
+            end
+          end
+
+          #  formats: "9.5.0"
+          #           "10.3 (Debian 10.3-2)"
+          def self.current_version
+            @current_version ||= pg_variable('server_version').split.first
+          end
+
+          def self.min_version
+            @min_version ||= '9.1'
+          end
+
+          def self.vendor
+            @vendor ||= 'PostgreSQL'
+          end
+
+          def self.pg_variable(name)
+            connection.exec("SHOW #{name};").first[name]
+          end
+        end
+      end
+    end
+  end
+end
--- a/spec/lib/core_ext/string_spec.rb
+++ b/spec/lib/core_ext/string_spec.rb
@ -1886,7 +1886,7 @@ RSpec.describe String do
            .to raise_error(Encoding::InvalidByteSequenceError)

          expect { subject.utf8_encode(from: 'gb2312') }
-            .not_to raise_error(Encoding::InvalidByteSequenceError)
+            .not_to raise_error
        end

        it 'uses the detected input encoding instead' do
--- a/spec/models/cti/caller_id_spec.rb
+++ b/spec/models/cti/caller_id_spec.rb
@ -113,8 +113,8 @@ RSpec.describe Cti::CallerId do
      context 'shared by multiple CallerIds' do
        context '(for different users)' do
          subject!(:caller_ids) do
-            [create(:caller_id, caller_id: number, user: User.last),
-             create(:caller_id, caller_id: number, user: User.offset(1).last)]
+            [create(:caller_id, caller_id: number, user: create(:user)),
+             create(:caller_id, caller_id: number, user: create(:user))]
          end

          it 'returns all corresponding CallerId records' do
@ -132,9 +132,8 @@ RSpec.describe Cti::CallerId do

        context '(some for the same user, some for another)' do
          subject!(:caller_ids) do
-            [create(:caller_id, caller_id: number, user: User.last),
-             create(:caller_id, caller_id: number, user: User.last),
-             create(:caller_id, caller_id: number, user: User.offset(1).last)]
+            [*create_list(:caller_id, 2, caller_id: number, user: create(:user)),
+             create(:caller_id, caller_id: number, user: create(:user))]
          end

          it 'returns one CallerId record per unique #user_id, by MAX(id)' do
--- a/spec/models/knowledge_base/category_spec.rb
+++ b/spec/models/knowledge_base/category_spec.rb
@ -14,7 +14,7 @@ RSpec.describe KnowledgeBase::Category, type: :model do

  it { is_expected.to have_many(:answers) }
  it { is_expected.to have_many(:children) }
-  it { is_expected.to belong_to(:parent) }
+  it { is_expected.to belong_to(:parent).optional }
  it { is_expected.to belong_to(:knowledge_base) }

  context 'in multilevel tree' do
--- a/test/unit/chat_test.rb
+++ b/test/unit/chat_test.rb
@ -49,6 +49,8 @@ class ChatTest < ActiveSupport::TestCase
  # see: https://github.com/zammad/zammad/issues/2353
  test 'chat event db connection test' do

+    skip "Can't properly disconnect while Spring is in use." if defined?(Spring)
+
    class DummyWs
      def send(msg)
        Rails.logger.info "WS send: #{msg}"