Merge branch 'master' into 'zj-wiki-page-versions'

# Conflicts:
#   Gemfile
#   Gemfile.lock

42 files changed, 290 insertions, 139 deletions

diff --git a/app/controllers/admin/broadcast_messages_controller.rb b/app/controllers/admin/broadcast_messages_controller.rb
index c49b6459452..a9109a1d4d0 100644
--- a/app/controllers/admin/broadcast_messages_controller.rb
+++ b/app/controllers/admin/broadcast_messages_controller.rb
@@ -1,4 +1,6 @@
 class Admin::BroadcastMessagesController < Admin::ApplicationController
+  include BroadcastMessagesHelper
+
   before_action :finder, only: [:edit, :update, :destroy]
 
   def index
@@ -37,7 +39,8 @@ class Admin::BroadcastMessagesController < Admin::ApplicationController
   end
 
   def preview
-    @broadcast_message = BroadcastMessage.new(broadcast_message_params)
+    broadcast_message = BroadcastMessage.new(broadcast_message_params)
+    render json: { message: render_broadcast_message(broadcast_message) }
   end
 
   protected
diff --git a/app/controllers/admin/cohorts_controller.rb b/app/controllers/admin/cohorts_controller.rb
index 9b77c554908..10d9d1b5345 100644
--- a/app/controllers/admin/cohorts_controller.rb
+++ b/app/controllers/admin/cohorts_controller.rb
@@ -1,6 +1,6 @@
 class Admin::CohortsController < Admin::ApplicationController
   def index
-    if current_application_settings.usage_ping_enabled
+    if Gitlab::CurrentSettings.usage_ping_enabled
       cohorts_results = Rails.cache.fetch('cohorts', expires_in: 1.day) do
         CohortsService.new.execute
       end
diff --git a/app/controllers/admin/gitaly_servers_controller.rb b/app/controllers/admin/gitaly_servers_controller.rb
new file mode 100644
index 00000000000..11c4dfe3d8d
--- /dev/null
+++ b/app/controllers/admin/gitaly_servers_controller.rb
@@ -0,0 +1,5 @@
+class Admin::GitalyServersController < Admin::ApplicationController
+  def index
+    @gitaly_servers = Gitaly::Server.all
+  end
+end
diff --git a/app/controllers/admin/services_controller.rb b/app/controllers/admin/services_controller.rb
index 4c3d336b3af..a7025b62ad7 100644
--- a/app/controllers/admin/services_controller.rb
+++ b/app/controllers/admin/services_controller.rb
@@ -1,6 +1,7 @@
 class Admin::ServicesController < Admin::ApplicationController
   include ServiceParams
 
+  before_action :whitelist_query_limiting, only: [:index]
   before_action :service, only: [:edit, :update]
 
   def index
@@ -37,4 +38,8 @@ class Admin::ServicesController < Admin::ApplicationController
   def service
     @service ||= Service.where(id: params[:id], template: true).first
   end
+
+  def whitelist_query_limiting
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42430')
+  end
 end
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index ee21d81f23e..b04bfaf3e49 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -2,7 +2,6 @@ require 'gon'
 require 'fogbugz'
 
 class ApplicationController < ActionController::Base
-  include Gitlab::CurrentSettings
   include Gitlab::GonHelper
   include GitlabRoutingHelper
   include PageLayoutHelper
@@ -28,7 +27,7 @@ class ApplicationController < ActionController::Base
 
   protect_from_forgery with: :exception
 
-  helper_method :can?, :current_application_settings
+  helper_method :can?
   helper_method :import_sources_enabled?, :github_import_enabled?, :gitea_import_enabled?, :github_import_configured?, :gitlab_import_enabled?, :gitlab_import_configured?, :bitbucket_import_enabled?, :bitbucket_import_configured?, :google_code_import_enabled?, :fogbugz_import_enabled?, :git_import_enabled?, :gitlab_project_import_enabled?
 
   rescue_from Encoding::CompatibilityError do |exception|
@@ -120,7 +119,7 @@ class ApplicationController < ActionController::Base
   end
 
   def after_sign_out_path_for(resource)
-    current_application_settings.after_sign_out_path.presence || new_user_session_path
+    Gitlab::CurrentSettings.after_sign_out_path.presence || new_user_session_path
   end
 
   def can?(object, action, subject = :global)
@@ -147,6 +146,8 @@ class ApplicationController < ActionController::Base
       format.html do
         render file: Rails.root.join("public", "404"), layout: false, status: "404"
       end
+      # Prevent the Rails CSRF protector from thinking a missing .js file is a JavaScript file
+      format.js { render json: '', status: :not_found, content_type: 'application/json' }
       format.any { head :not_found }
     end
   end
@@ -266,15 +267,15 @@ class ApplicationController < ActionController::Base
   end
 
   def import_sources_enabled?
-    !current_application_settings.import_sources.empty?
+    !Gitlab::CurrentSettings.import_sources.empty?
   end
 
   def github_import_enabled?
-    current_application_settings.import_sources.include?('github')
+    Gitlab::CurrentSettings.import_sources.include?('github')
   end
 
   def gitea_import_enabled?
-    current_application_settings.import_sources.include?('gitea')
+    Gitlab::CurrentSettings.import_sources.include?('gitea')
   end
 
   def github_import_configured?
@@ -282,7 +283,7 @@ class ApplicationController < ActionController::Base
   end
 
   def gitlab_import_enabled?
-    request.host != 'gitlab.com' && current_application_settings.import_sources.include?('gitlab')
+    request.host != 'gitlab.com' && Gitlab::CurrentSettings.import_sources.include?('gitlab')
   end
 
   def gitlab_import_configured?
@@ -290,7 +291,7 @@ class ApplicationController < ActionController::Base
   end
 
   def bitbucket_import_enabled?
-    current_application_settings.import_sources.include?('bitbucket')
+    Gitlab::CurrentSettings.import_sources.include?('bitbucket')
   end
 
   def bitbucket_import_configured?
@@ -298,19 +299,19 @@ class ApplicationController < ActionController::Base
   end
 
   def google_code_import_enabled?
-    current_application_settings.import_sources.include?('google_code')
+    Gitlab::CurrentSettings.import_sources.include?('google_code')
   end
 
   def fogbugz_import_enabled?
-    current_application_settings.import_sources.include?('fogbugz')
+    Gitlab::CurrentSettings.import_sources.include?('fogbugz')
   end
 
   def git_import_enabled?
-    current_application_settings.import_sources.include?('git')
+    Gitlab::CurrentSettings.import_sources.include?('git')
   end
 
   def gitlab_project_import_enabled?
-    current_application_settings.import_sources.include?('gitlab_project')
+    Gitlab::CurrentSettings.import_sources.include?('gitlab_project')
   end
 
   # U2F (universal 2nd factor) devices need a unique identifier for the application
diff --git a/app/controllers/boards/issues_controller.rb b/app/controllers/boards/issues_controller.rb
index f8049b20b9f..ee23ee0bcc3 100644
--- a/app/controllers/boards/issues_controller.rb
+++ b/app/controllers/boards/issues_controller.rb
@@ -2,6 +2,7 @@ module Boards
   class IssuesController < Boards::ApplicationController
     include BoardsResponses
 
+    before_action :whitelist_query_limiting, only: [:index, :update]
     before_action :authorize_read_issue, only: [:index]
     before_action :authorize_create_issue, only: [:create]
     before_action :authorize_update_issue, only: [:update]
@@ -92,5 +93,10 @@ module Boards
         }
       )
     end
+
+    def whitelist_query_limiting
+      # Also see https://gitlab.com/gitlab-org/gitlab-ce/issues/42439
+      Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42428')
+    end
   end
 end
diff --git a/app/controllers/concerns/enforces_two_factor_authentication.rb b/app/controllers/concerns/enforces_two_factor_authentication.rb
index 688e8bd4a37..997af4ab9e9 100644
--- a/app/controllers/concerns/enforces_two_factor_authentication.rb
+++ b/app/controllers/concerns/enforces_two_factor_authentication.rb
@@ -20,13 +20,13 @@ module EnforcesTwoFactorAuthentication
   end
 
   def two_factor_authentication_required?
-    current_application_settings.require_two_factor_authentication? ||
+    Gitlab::CurrentSettings.require_two_factor_authentication? ||
       current_user.try(:require_two_factor_authentication_from_group?)
   end
 
   def two_factor_authentication_reason(global: -> {}, group: -> {})
     if two_factor_authentication_required?
-      if current_application_settings.require_two_factor_authentication?
+      if Gitlab::CurrentSettings.require_two_factor_authentication?
         global.call
       else
         groups = current_user.expanded_groups_requiring_two_factor_authentication.reorder(name: :asc)
@@ -36,7 +36,7 @@ module EnforcesTwoFactorAuthentication
   end
 
   def two_factor_grace_period
-    periods = [current_application_settings.two_factor_grace_period]
+    periods = [Gitlab::CurrentSettings.two_factor_grace_period]
     periods << current_user.two_factor_grace_period if current_user.try(:require_two_factor_authentication_from_group?)
     periods.min
   end
diff --git a/app/controllers/concerns/group_tree.rb b/app/controllers/concerns/group_tree.rb
index b569029283f..fafb10090ca 100644
--- a/app/controllers/concerns/group_tree.rb
+++ b/app/controllers/concerns/group_tree.rb
@@ -2,7 +2,11 @@ module GroupTree
   # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def render_group_tree(groups)
     @groups = if params[:filter].present?
-                Gitlab::GroupHierarchy.new(groups.search(params[:filter]))
+                # We find the ancestors by ID of the search results here.
+                # Otherwise the ancestors would also have filters applied,
+                # which would cause them not to be preloaded.
+                group_ids = groups.search(params[:filter]).select(:id)
+                Gitlab::GroupHierarchy.new(Group.where(id: group_ids))
                   .base_and_ancestors
               else
                 # Only show root groups if no parent-id is given
diff --git a/app/controllers/concerns/issuable_collections.rb b/app/controllers/concerns/issuable_collections.rb
index b25e753a5ad..0d7ee06deb6 100644
--- a/app/controllers/concerns/issuable_collections.rb
+++ b/app/controllers/concerns/issuable_collections.rb
@@ -12,11 +12,9 @@ module IssuableCollections
 
   # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def set_issuables_index
-    @issuables          = issuables_collection
-    @issuables          = @issuables.page(params[:page])
-    @issuable_meta_data = issuable_meta_data(@issuables, collection_type)
-    @total_pages        = issuable_page_count
+    @issuables = issuables_collection
 
+    set_pagination
     return if redirect_out_of_range(@total_pages)
 
     if params[:label_name].present?
@@ -35,14 +33,26 @@ module IssuableCollections
       @users.push(author) if author
     end
   end
+
+  def set_pagination
+    return if pagination_disabled?
+
+    @issuables          = @issuables.page(params[:page])
+    @issuable_meta_data = issuable_meta_data(@issuables, collection_type)
+    @total_pages        = issuable_page_count
+  end
   # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
+  def pagination_disabled?
+    false
+  end
+
   def issuables_collection
     finder.execute.preload(preload_for_collection)
   end
 
   def redirect_out_of_range(total_pages)
-    return false if total_pages.zero?
+    return false if total_pages.nil? || total_pages.zero?
 
     out_of_range = @issuables.current_page > total_pages # rubocop:disable Gitlab/ModuleWithInstanceVariables
 
@@ -84,6 +94,7 @@ module IssuableCollections
       @filter_params[:project_id] = @project.id
     elsif @group
       @filter_params[:group_id] = @group.id
+      @filter_params[:include_subgroups] = true
     else
       # TODO: this filter ignore issues/mr created in public or
       # internal repos where you are not a member. Enable this filter
diff --git a/app/controllers/concerns/requires_whitelisted_monitoring_client.rb b/app/controllers/concerns/requires_whitelisted_monitoring_client.rb
index 0218ac83441..88d1b34bb06 100644
--- a/app/controllers/concerns/requires_whitelisted_monitoring_client.rb
+++ b/app/controllers/concerns/requires_whitelisted_monitoring_client.rb
@@ -1,8 +1,6 @@
 module RequiresWhitelistedMonitoringClient
   extend ActiveSupport::Concern
 
-  include Gitlab::CurrentSettings
-
   included do
     before_action :validate_ip_whitelisted_or_valid_token!
   end
@@ -26,7 +24,7 @@ module RequiresWhitelistedMonitoringClient
     token.present? &&
       ActiveSupport::SecurityUtils.variable_size_secure_compare(
         token,
-        current_application_settings.health_check_access_token
+        Gitlab::CurrentSettings.health_check_access_token
       )
   end
 
diff --git a/app/controllers/concerns/uploads_actions.rb b/app/controllers/concerns/uploads_actions.rb
index a6fb1f40001..7ad79a1e56c 100644
--- a/app/controllers/concerns/uploads_actions.rb
+++ b/app/controllers/concerns/uploads_actions.rb
@@ -1,6 +1,8 @@
 module UploadsActions
   include Gitlab::Utils::StrongMemoize
 
+  UPLOAD_MOUNTS = %w(avatar attachment file logo header_logo).freeze
+
   def create
     link_to_file = UploadService.new(model, params[:file], uploader_class).execute
 
@@ -17,34 +19,71 @@ module UploadsActions
     end
   end
 
+  # This should either
+  #   - send the file directly
+  #   - or redirect to its URL
+  #
   def show
     return render_404 unless uploader.exists?
 
-    disposition = uploader.image_or_video? ? 'inline' : 'attachment'
-
-    expires_in 0.seconds, must_revalidate: true, private: true
+    if uploader.file_storage?
+      disposition = uploader.image_or_video? ? 'inline' : 'attachment'
+      expires_in 0.seconds, must_revalidate: true, private: true
 
-    send_file uploader.file.path, disposition: disposition
+      send_file uploader.file.path, disposition: disposition
+    else
+      redirect_to uploader.url
+    end
   end
 
   private
 
+  def uploader_class
+    raise NotImplementedError
+  end
+
+  def upload_mount
+    mounted_as = params[:mounted_as]
+    mounted_as if UPLOAD_MOUNTS.include?(mounted_as)
+  end
+
+  def uploader_mounted?
+    upload_model_class < CarrierWave::Mount::Extension && !upload_mount.nil?
+  end
+
   def uploader
     strong_memoize(:uploader) do
-      return if show_model.nil?
+      if uploader_mounted?
+        model.public_send(upload_mount) # rubocop:disable GitlabSecurity/PublicSend
+      else
+        build_uploader_from_upload || build_uploader_from_params
+      end
+    end
+  end
 
-      file_uploader = FileUploader.new(show_model, params[:secret])
-      file_uploader.retrieve_from_store!(params[:filename])
+  def build_uploader_from_upload
+    return nil unless params[:secret] && params[:filename]
 
-      file_uploader
-    end
+    upload_path = uploader_class.upload_path(params[:secret], params[:filename])
+    upload = Upload.find_by(uploader: uploader_class.to_s, path: upload_path)
+    upload&.build_uploader
+  end
+
+  def build_uploader_from_params
+    uploader = uploader_class.new(model, secret: params[:secret])
+    uploader.retrieve_from_store!(params[:filename])
+    uploader
   end
 
   def image_or_video?
     uploader && uploader.exists? && uploader.image_or_video?
   end
 
-  def uploader_class
-    FileUploader
+  def find_model
+    nil
+  end
+
+  def model
+    strong_memoize(:model) { find_model }
   end
 end
diff --git a/app/controllers/groups/labels_controller.rb b/app/controllers/groups/labels_controller.rb
index dda59262483..f3a9e591c3e 100644
--- a/app/controllers/groups/labels_controller.rb
+++ b/app/controllers/groups/labels_controller.rb
@@ -54,7 +54,7 @@ class Groups::LabelsController < Groups::ApplicationController
 
     respond_to do |format|
       format.html do
-        redirect_to group_labels_path(@group), status: 302, notice: 'Label was removed'
+        redirect_to group_labels_path(@group), status: 302, notice: "#{@label.name} deleted permanently"
       end
       format.js
     end
diff --git a/app/controllers/groups/uploads_controller.rb b/app/controllers/groups/uploads_controller.rb
index e6bd9806401..f1578f75e88 100644
--- a/app/controllers/groups/uploads_controller.rb
+++ b/app/controllers/groups/uploads_controller.rb
@@ -7,29 +7,23 @@ class Groups::UploadsController < Groups::ApplicationController
 
   private
 
-  def show_model
-    strong_memoize(:show_model) do
-      group_id = params[:group_id]
-
-      Group.find_by_full_path(group_id)
-    end
+  def upload_model_class
+    Group
   end
 
-  def authorize_upload_file!
-    render_404 unless can?(current_user, :upload_file, group)
+  def uploader_class
+    NamespaceFileUploader
   end
 
-  def uploader
-    strong_memoize(:uploader) do
-      file_uploader = uploader_class.new(show_model, params[:secret])
-      file_uploader.retrieve_from_store!(params[:filename])
-      file_uploader
-    end
-  end
+  def find_model
+    return @group if @group
 
-  def uploader_class
-    NamespaceFileUploader
+    group_id = params[:group_id]
+
+    Group.find_by_full_path(group_id)
   end
 
-  alias_method :model, :group
+  def authorize_upload_file!
+    render_404 unless can?(current_user, :upload_file, group)
+  end
 end
diff --git a/app/controllers/groups_controller.rb b/app/controllers/groups_controller.rb
index eb53a522f90..7d129c5dece 100644
--- a/app/controllers/groups_controller.rb
+++ b/app/controllers/groups_controller.rb
@@ -10,7 +10,7 @@ class GroupsController < Groups::ApplicationController
   before_action :group, except: [:index, :new, :create]
 
   # Authorize
-  before_action :authorize_admin_group!, only: [:edit, :update, :destroy, :projects]
+  before_action :authorize_admin_group!, only: [:edit, :update, :destroy, :projects, :transfer]
   before_action :authorize_create_group!, only: [:new]
 
   before_action :group_projects, only: [:projects, :activity, :issues, :merge_requests]
@@ -94,6 +94,19 @@ class GroupsController < Groups::ApplicationController
     redirect_to root_path, status: 302, alert: "Group '#{@group.name}' was scheduled for deletion."
   end
 
+  def transfer
+    parent_group = Group.find_by(id: params[:new_parent_group_id])
+    service = ::Groups::TransferService.new(@group, current_user)
+
+    if service.execute(parent_group)
+      flash[:notice] = "Group '#{@group.name}' was successfully transferred."
+      redirect_to group_path(@group)
+    else
+      flash.now[:alert] = service.error
+      render :edit
+    end
+  end
+
   protected
 
   def authorize_create_group!
@@ -118,10 +131,10 @@ class GroupsController < Groups::ApplicationController
   end
 
   def group_params
-    params.require(:group).permit(group_params_ce)
+    params.require(:group).permit(group_params_attributes)
   end
 
-  def group_params_ce
+  def group_params_attributes
     [
       :avatar,
       :description,
@@ -150,7 +163,6 @@ class GroupsController < Groups::ApplicationController
     @projects = GroupProjectsFinder.new(params: params, group: group, options: options, current_user: current_user)
                   .execute
                   .includes(:namespace)
-                  .page(params[:page])
 
     @events = EventCollection
       .new(@projects, offset: params[:offset].to_i, filter: event_filter)
diff --git a/app/controllers/health_controller.rb b/app/controllers/health_controller.rb
index a931b456a93..16abf7bab7e 100644
--- a/app/controllers/health_controller.rb
+++ b/app/controllers/health_controller.rb
@@ -8,7 +8,8 @@ class HealthController < ActionController::Base
     Gitlab::HealthChecks::Redis::CacheCheck,
     Gitlab::HealthChecks::Redis::QueuesCheck,
     Gitlab::HealthChecks::Redis::SharedStateCheck,
-    Gitlab::HealthChecks::FsShardsCheck
+    Gitlab::HealthChecks::FsShardsCheck,
+    Gitlab::HealthChecks::GitalyCheck
   ].freeze
 
   def readiness
diff --git a/app/controllers/help_controller.rb b/app/controllers/help_controller.rb
index 38f379dbf4f..a394521698c 100644
--- a/app/controllers/help_controller.rb
+++ b/app/controllers/help_controller.rb
@@ -5,7 +5,7 @@ class HelpController < ApplicationController
 
   # Taken from Jekyll
   # https://github.com/jekyll/jekyll/blob/3.5-stable/lib/jekyll/document.rb#L13
-  YAML_FRONT_MATTER_REGEXP = %r!\A(---\s*\n.*?\n?)^((---|\.\.\.)\s*$\n?)!m
+  YAML_FRONT_MATTER_REGEXP = /\A(---\s*\n.*?\n?)^((---|\.\.\.)\s*$\n?)/m
 
   def index
     # Remove YAML frontmatter so that it doesn't look weird
diff --git a/app/controllers/import/gitlab_projects_controller.rb b/app/controllers/import/gitlab_projects_controller.rb
index 567957ba2cb..f22df992fe9 100644
--- a/app/controllers/import/gitlab_projects_controller.rb
+++ b/app/controllers/import/gitlab_projects_controller.rb
@@ -1,4 +1,5 @@
 class Import::GitlabProjectsController < Import::BaseController
+  before_action :whitelist_query_limiting, only: [:create]
   before_action :verify_gitlab_project_import_enabled
 
   def new
@@ -40,4 +41,8 @@ class Import::GitlabProjectsController < Import::BaseController
       :path, :namespace_id, :file
     )
   end
+
+  def whitelist_query_limiting
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42437')
+  end
 end
diff --git a/app/controllers/invites_controller.rb b/app/controllers/invites_controller.rb
index 04b29aa2384..52430ea771f 100644
--- a/app/controllers/invites_controller.rb
+++ b/app/controllers/invites_controller.rb
@@ -51,7 +51,7 @@ class InvitesController < ApplicationController
     return if current_user
 
     notice = "To accept this invitation, sign in"
-    notice << " or create an account" if current_application_settings.allow_signup?
+    notice << " or create an account" if Gitlab::CurrentSettings.allow_signup?
     notice << "."
 
     store_location_for :user, request.fullpath
diff --git a/app/controllers/koding_controller.rb b/app/controllers/koding_controller.rb
index 6b1e64ce819..745abf3c0f5 100644
--- a/app/controllers/koding_controller.rb
+++ b/app/controllers/koding_controller.rb
@@ -10,6 +10,6 @@ class KodingController < ApplicationController
   private
 
   def check_integration!
-    render_404 unless current_application_settings.koding_enabled?
+    render_404 unless Gitlab::CurrentSettings.koding_enabled?
   end
 end
diff --git a/app/controllers/oauth/applications_controller.rb b/app/controllers/oauth/applications_controller.rb
index 2443f529c7b..6a21a3f77ad 100644
--- a/app/controllers/oauth/applications_controller.rb
+++ b/app/controllers/oauth/applications_controller.rb
@@ -1,5 +1,4 @@
 class Oauth::ApplicationsController < Doorkeeper::ApplicationsController
-  include Gitlab::CurrentSettings
   include Gitlab::GonHelper
   include PageLayoutHelper
   include OauthApplications
@@ -31,7 +30,7 @@ class Oauth::ApplicationsController < Doorkeeper::ApplicationsController
   private
 
   def verify_user_oauth_applications_enabled
-    return if current_application_settings.user_oauth_applications?
+    return if Gitlab::CurrentSettings.user_oauth_applications?
 
     redirect_to profile_path
   end
diff --git a/app/controllers/omniauth_callbacks_controller.rb b/app/controllers/omniauth_callbacks_controller.rb
index d631d09f1b8..83c9a3f035e 100644
--- a/app/controllers/omniauth_callbacks_controller.rb
+++ b/app/controllers/omniauth_callbacks_controller.rb
@@ -145,7 +145,7 @@ class OmniauthCallbacksController < Devise::OmniauthCallbacksController
     label = Gitlab::OAuth::Provider.label_for(oauth['provider'])
     message = "Signing in using your #{label} account without a pre-existing GitLab account is not allowed."
 
-    if current_application_settings.allow_signup?
+    if Gitlab::CurrentSettings.allow_signup?
       message << " Create a GitLab account first, and then connect it to your #{label} account."
     end
 
diff --git a/app/controllers/passwords_controller.rb b/app/controllers/passwords_controller.rb
index 57761bfbe26..331583c49e6 100644
--- a/app/controllers/passwords_controller.rb
+++ b/app/controllers/passwords_controller.rb
@@ -1,6 +1,4 @@
 class PasswordsController < Devise::PasswordsController
-  include Gitlab::CurrentSettings
-
   skip_before_action :require_no_authentication, only: [:edit, :update]
 
   before_action :resource_from_email, only: [:create]
@@ -46,7 +44,7 @@ class PasswordsController < Devise::PasswordsController
     if resource
       return if resource.allow_password_authentication?
     else
-      return if current_application_settings.password_authentication_enabled?
+      return if Gitlab::CurrentSettings.password_authentication_enabled?
     end
 
     redirect_to after_sending_reset_password_instructions_path_for(resource_name),
diff --git a/app/controllers/projects/clusters/gcp_controller.rb b/app/controllers/projects/clusters/gcp_controller.rb
index 4fc515bd03e..94d33b91562 100644
--- a/app/controllers/projects/clusters/gcp_controller.rb
+++ b/app/controllers/projects/clusters/gcp_controller.rb
@@ -42,7 +42,7 @@ class Projects::Clusters::GcpController < Projects::ApplicationController
     when 'true'
       return
     when 'false'
-      flash[:alert] = _('Please <a href=%{link_to_billing} target="_blank" rel="noopener noreferrer">enable billing for one of your projects to be able to create a cluster</a>, then try again.').html_safe % { link_to_billing: "https://console.cloud.google.com/freetrial?utm_campaign=2018_cpanel&utm_source=gitlab&utm_medium=referral" }
+      flash[:alert] = _('Please <a href=%{link_to_billing} target="_blank" rel="noopener noreferrer">enable billing for one of your projects to be able to create a Kubernetes cluster</a>, then try again.').html_safe % { link_to_billing: "https://console.cloud.google.com/freetrial?utm_campaign=2018_cpanel&utm_source=gitlab&utm_medium=referral" }
     else
       flash[:alert] = _('We could not verify that one of your projects on GCP has billing enabled. Please try again.')
     end
diff --git a/app/controllers/projects/clusters_controller.rb b/app/controllers/projects/clusters_controller.rb
index 1dc7f1b3a7f..142e8b6e4bc 100644
--- a/app/controllers/projects/clusters_controller.rb
+++ b/app/controllers/projects/clusters_controller.rb
@@ -41,7 +41,7 @@ class Projects::ClustersController < Projects::ApplicationController
           head :no_content
         end
         format.html do
-          flash[:notice] = "Cluster was successfully updated."
+          flash[:notice] = _('Kubernetes cluster was successfully updated.')
           redirect_to project_cluster_path(project, cluster)
         end
       end
@@ -55,10 +55,10 @@ class Projects::ClustersController < Projects::ApplicationController
 
   def destroy
     if cluster.destroy
-      flash[:notice] = "Cluster integration was successfully removed."
+      flash[:notice] = _('Kubernetes cluster integration was successfully removed.')
       redirect_to project_clusters_path(project), status: 302
     else
-      flash[:notice] = "Cluster integration was not removed."
+      flash[:notice] = _('Kubernetes cluster integration was not removed.')
       render :show
     end
   end
diff --git a/app/controllers/projects/commits_controller.rb b/app/controllers/projects/commits_controller.rb
index 0a40c67368f..1d910e461b1 100644
--- a/app/controllers/projects/commits_controller.rb
+++ b/app/controllers/projects/commits_controller.rb
@@ -4,6 +4,7 @@ class Projects::CommitsController < Projects::ApplicationController
   include ExtractsPath
   include RendersCommits
 
+  before_action :whitelist_query_limiting
   before_action :require_non_empty_project
   before_action :assign_ref_vars
   before_action :authorize_download_code!
@@ -65,4 +66,8 @@ class Projects::CommitsController < Projects::ApplicationController
     @commits = @commits.with_pipeline_status
     @commits = prepare_commits_for_rendering(@commits)
   end
+
+  def whitelist_query_limiting
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42330')
+  end
 end
diff --git a/app/controllers/projects/cycle_analytics_controller.rb b/app/controllers/projects/cycle_analytics_controller.rb
index 88ac3ad046b..d1b8fd80c4e 100644
--- a/app/controllers/projects/cycle_analytics_controller.rb
+++ b/app/controllers/projects/cycle_analytics_controller.rb
@@ -3,6 +3,7 @@ class Projects::CycleAnalyticsController < Projects::ApplicationController
   include ActionView::Helpers::TextHelper
   include CycleAnalyticsParams
 
+  before_action :whitelist_query_limiting, only: [:show]
   before_action :authorize_read_cycle_analytics!
 
   def show
@@ -31,4 +32,8 @@ class Projects::CycleAnalyticsController < Projects::ApplicationController
       permissions: @cycle_analytics.permissions(user: current_user)
     }
   end
+
+  def whitelist_query_limiting
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42671')
+  end
 end
diff --git a/app/controllers/projects/forks_controller.rb b/app/controllers/projects/forks_controller.rb
index 68978f8fdd1..f43bba18d81 100644
--- a/app/controllers/projects/forks_controller.rb
+++ b/app/controllers/projects/forks_controller.rb
@@ -2,6 +2,7 @@ class Projects::ForksController < Projects::ApplicationController
   include ContinueParams
 
   # Authorize
+  before_action :whitelist_query_limiting, only: [:create]
   before_action :require_non_empty_project
   before_action :authorize_download_code!
   before_action :authenticate_user!, only: [:new, :create]
@@ -54,4 +55,8 @@ class Projects::ForksController < Projects::ApplicationController
       render :error
     end
   end
+
+  def whitelist_query_limiting
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42335')
+  end
 end
diff --git a/app/controllers/projects/issues_controller.rb b/app/controllers/projects/issues_controller.rb
index 384f18b316c..515cb08f1fc 100644
--- a/app/controllers/projects/issues_controller.rb
+++ b/app/controllers/projects/issues_controller.rb
@@ -8,6 +8,7 @@ class Projects::IssuesController < Projects::ApplicationController
 
   prepend_before_action :authenticate_user!, only: [:new]
 
+  before_action :whitelist_query_limiting, only: [:create, :create_merge_request, :move, :bulk_update]
   before_action :check_issues_available!
   before_action :issue, except: [:index, :new, :create, :bulk_update]
   before_action :set_issuables_index, only: [:index]
@@ -247,4 +248,13 @@ class Projects::IssuesController < Projects::ApplicationController
     @finder_type = IssuesFinder
     super
   end
+
+  def whitelist_query_limiting
+    # Also see the following issues:
+    #
+    # 1. https://gitlab.com/gitlab-org/gitlab-ce/issues/42423
+    # 2. https://gitlab.com/gitlab-org/gitlab-ce/issues/42424
+    # 3. https://gitlab.com/gitlab-org/gitlab-ce/issues/42426
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42422')
+  end
 end
diff --git a/app/controllers/projects/lfs_storage_controller.rb b/app/controllers/projects/lfs_storage_controller.rb
index 293869345bd..941638db427 100644
--- a/app/controllers/projects/lfs_storage_controller.rb
+++ b/app/controllers/projects/lfs_storage_controller.rb
@@ -60,7 +60,7 @@ class Projects::LfsStorageController < Projects::GitHttpClientController
 
   def store_file(oid, size, tmp_file)
     # Define tmp_file_path early because we use it in "ensure"
-    tmp_file_path = File.join("#{Gitlab.config.lfs.storage_path}/tmp/upload", tmp_file)
+    tmp_file_path = File.join(LfsObjectUploader.workhorse_upload_path, tmp_file)
 
     object = LfsObject.find_or_create_by(oid: oid, size: size)
     file_exists = object.file.exists? || move_tmp_file_to_storage(object, tmp_file_path)
diff --git a/app/controllers/projects/merge_requests/creations_controller.rb b/app/controllers/projects/merge_requests/creations_controller.rb
index 0df80fa700f..a5a2d54ba82 100644
--- a/app/controllers/projects/merge_requests/creations_controller.rb
+++ b/app/controllers/projects/merge_requests/creations_controller.rb
@@ -4,6 +4,7 @@ class Projects::MergeRequests::CreationsController < Projects::MergeRequests::Ap
   include RendersCommits
 
   skip_before_action :merge_request
+  before_action :whitelist_query_limiting, only: [:create]
   before_action :authorize_create_merge_request!
   before_action :apply_diff_view_cookie!, only: [:diffs, :diff_for_path]
   before_action :build_merge_request, except: [:create]
@@ -125,4 +126,8 @@ class Projects::MergeRequests::CreationsController < Projects::MergeRequests::Ap
       @project.forked_from_project
     end
   end
+
+  def whitelist_query_limiting
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42384')
+  end
 end
diff --git a/app/controllers/projects/merge_requests_controller.rb b/app/controllers/projects/merge_requests_controller.rb
index 2e8a738b6d9..8af4e379f0a 100644
--- a/app/controllers/projects/merge_requests_controller.rb
+++ b/app/controllers/projects/merge_requests_controller.rb
@@ -7,6 +7,7 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
   include IssuableCollections
 
   skip_before_action :merge_request, only: [:index, :bulk_update]
+  before_action :whitelist_query_limiting, only: [:assign_related_issues, :update]
   before_action :authorize_update_issuable!, only: [:close, :edit, :update, :remove_wip, :sort]
   before_action :set_issuables_index, only: [:index]
   before_action :authenticate_user!, only: [:assign_related_issues]
@@ -339,4 +340,9 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
 
     access_denied! unless access_check
   end
+
+  def whitelist_query_limiting
+    # Also see https://gitlab.com/gitlab-org/gitlab-ce/issues/42441
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42438')
+  end
 end
diff --git a/app/controllers/projects/milestones_controller.rb b/app/controllers/projects/milestones_controller.rb
index 0f70efbce40..75b17d05e22 100644
--- a/app/controllers/projects/milestones_controller.rb
+++ b/app/controllers/projects/milestones_controller.rb
@@ -83,7 +83,7 @@ class Projects::MilestonesController < Projects::ApplicationController
     Milestones::DestroyService.new(project, current_user).execute(milestone)
 
     respond_to do |format|
-      format.html { redirect_to namespace_project_milestones_path, status: 302 }
+      format.html { redirect_to namespace_project_milestones_path, status: 303 }
       format.js { head :ok }
     end
   end
diff --git a/app/controllers/projects/network_controller.rb b/app/controllers/projects/network_controller.rb
index fb68dd771a1..3b10a93e97f 100644
--- a/app/controllers/projects/network_controller.rb
+++ b/app/controllers/projects/network_controller.rb
@@ -2,6 +2,7 @@ class Projects::NetworkController < Projects::ApplicationController
   include ExtractsPath
   include ApplicationHelper
 
+  before_action :whitelist_query_limiting
   before_action :require_non_empty_project
   before_action :assign_ref_vars
   before_action :authorize_download_code!
@@ -35,4 +36,8 @@ class Projects::NetworkController < Projects::ApplicationController
     @options[:extended_sha1] = params[:extended_sha1]
     @commit = @repo.commit(@options[:extended_sha1])
   end
+
+  def whitelist_query_limiting
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42333')
+  end
 end
diff --git a/app/controllers/projects/notes_controller.rb b/app/controllers/projects/notes_controller.rb
index 5940fae8dd0..4f8978c93c3 100644
--- a/app/controllers/projects/notes_controller.rb
+++ b/app/controllers/projects/notes_controller.rb
@@ -2,6 +2,7 @@ class Projects::NotesController < Projects::ApplicationController
   include NotesActions
   include ToggleAwardEmoji
 
+  before_action :whitelist_query_limiting, only: [:create]
   before_action :authorize_read_note!
   before_action :authorize_create_note!, only: [:create]
   before_action :authorize_resolve_note!, only: [:resolve, :unresolve]
@@ -79,4 +80,8 @@ class Projects::NotesController < Projects::ApplicationController
 
     access_denied! unless can?(current_user, :create_note, noteable)
   end
+
+  def whitelist_query_limiting
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42383')
+  end
 end
diff --git a/app/controllers/projects/pipelines_controller.rb b/app/controllers/projects/pipelines_controller.rb
index e146d0d3cd5..78d109cf33e 100644
--- a/app/controllers/projects/pipelines_controller.rb
+++ b/app/controllers/projects/pipelines_controller.rb
@@ -1,4 +1,5 @@
 class Projects::PipelinesController < Projects::ApplicationController
+  before_action :whitelist_query_limiting, only: [:create, :retry]
   before_action :pipeline, except: [:index, :new, :create, :charts]
   before_action :commit, only: [:show, :builds, :failures]
   before_action :authorize_read_pipeline!
@@ -166,4 +167,9 @@ class Projects::PipelinesController < Projects::ApplicationController
   def commit
     @commit ||= @pipeline.commit
   end
+
+  def whitelist_query_limiting
+    # Also see https://gitlab.com/gitlab-org/gitlab-ce/issues/42343
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42339')
+  end
 end
diff --git a/app/controllers/projects/uploads_controller.rb b/app/controllers/projects/uploads_controller.rb
index 4685bbe80b4..f5cf089ad98 100644
--- a/app/controllers/projects/uploads_controller.rb
+++ b/app/controllers/projects/uploads_controller.rb
@@ -1,6 +1,7 @@
 class Projects::UploadsController < Projects::ApplicationController
   include UploadsActions
 
+  # These will kick you out if you don't have access.
   skip_before_action :project, :repository,
     if: -> { action_name == 'show' && image_or_video? }
 
@@ -8,14 +9,20 @@ class Projects::UploadsController < Projects::ApplicationController
 
   private
 
-  def show_model
-    strong_memoize(:show_model) do
-      namespace = params[:namespace_id]
-      id = params[:project_id]
+  def upload_model_class
+    Project
+  end
 
-      Project.find_by_full_path("#{namespace}/#{id}")
-    end
+  def uploader_class
+    FileUploader
   end
 
-  alias_method :model, :project
+  def find_model
+    return @project if @project
+
+    namespace = params[:namespace_id]
+    id = params[:project_id]
+
+    Project.find_by_full_path("#{namespace}/#{id}")
+  end
 end
diff --git a/app/controllers/projects/wikis_controller.rb b/app/controllers/projects/wikis_controller.rb
index 730f20bc086..c4930d3d18d 100644
--- a/app/controllers/projects/wikis_controller.rb
+++ b/app/controllers/projects/wikis_controller.rb
@@ -54,8 +54,8 @@ class Projects::WikisController < Projects::ApplicationController
     else
       render 'edit'
     end
-  rescue WikiPage::PageChangedError
-    @conflict = true
+  rescue WikiPage::PageChangedError, WikiPage::PageRenameError => e
+    @error = e
     render 'edit'
   end
 
diff --git a/app/controllers/projects_controller.rb b/app/controllers/projects_controller.rb
index e6e2b219e6a..72573e0765d 100644
--- a/app/controllers/projects_controller.rb
+++ b/app/controllers/projects_controller.rb
@@ -3,6 +3,7 @@ class ProjectsController < Projects::ApplicationController
   include ExtractsPath
   include PreviewMarkdown
 
+  before_action :whitelist_query_limiting, only: [:create]
   before_action :authenticate_user!, except: [:index, :show, :activity, :refs]
   before_action :redirect_git_extension, only: [:show]
   before_action :project, except: [:index, :new, :create]
@@ -394,7 +395,7 @@ class ProjectsController < Projects::ApplicationController
   end
 
   def project_export_enabled
-    render_404 unless current_application_settings.project_export_enabled?
+    render_404 unless Gitlab::CurrentSettings.project_export_enabled?
   end
 
   def redirect_git_extension
@@ -403,6 +404,10 @@ class ProjectsController < Projects::ApplicationController
     # to
     #   localhost/group/project
     #
-    redirect_to request.original_url.sub(/\.git\/?\Z/, '') if params[:format] == 'git'
+    redirect_to request.original_url.sub(%r{\.git/?\Z}, '') if params[:format] == 'git'
+  end
+
+  def whitelist_query_limiting
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42440')
   end
 end
diff --git a/app/controllers/registrations_controller.rb b/app/controllers/registrations_controller.rb
index d9142311b6f..1848c806c41 100644
--- a/app/controllers/registrations_controller.rb
+++ b/app/controllers/registrations_controller.rb
@@ -1,6 +1,8 @@
 class RegistrationsController < Devise::RegistrationsController
   include Recaptcha::Verify
 
+  before_action :whitelist_query_limiting, only: [:destroy]
+
   def new
     redirect_to(new_user_session_path)
   end
@@ -83,4 +85,8 @@ class RegistrationsController < Devise::RegistrationsController
   def devise_mapping
     @devise_mapping ||= Devise.mappings[:user]
   end
+
+  def whitelist_query_limiting
+    Gitlab::QueryLimiting.whitelist('https://gitlab.com/gitlab-org/gitlab-ce/issues/42380')
+  end
 end
diff --git a/app/controllers/root_controller.rb b/app/controllers/root_controller.rb
index 19e38993038..8acefd58e77 100644
--- a/app/controllers/root_controller.rb
+++ b/app/controllers/root_controller.rb
@@ -23,7 +23,7 @@ class RootController < Dashboard::ProjectsController
 
   def redirect_unlogged_user
     if redirect_to_home_page_url?
-      redirect_to(current_application_settings.home_page_url)
+      redirect_to(Gitlab::CurrentSettings.home_page_url)
     else
       redirect_to(new_user_session_path)
     end
@@ -48,9 +48,9 @@ class RootController < Dashboard::ProjectsController
   def redirect_to_home_page_url?
     # If user is not signed-in and tries to access root_path - redirect him to landing page
     # Don't redirect to the default URL to prevent endless redirections
-    return false unless current_application_settings.home_page_url.present?
+    return false unless Gitlab::CurrentSettings.home_page_url.present?
 
-    home_page_url = current_application_settings.home_page_url.chomp('/')
+    home_page_url = Gitlab::CurrentSettings.home_page_url.chomp('/')
     root_urls = [Gitlab.config.gitlab['url'].chomp('/'), root_url.chomp('/')]
 
     root_urls.exclude?(home_page_url)
diff --git a/app/controllers/uploads_controller.rb b/app/controllers/uploads_controller.rb
index 16a74f82d3f..3d227b0a955 100644
--- a/app/controllers/uploads_controller.rb
+++ b/app/controllers/uploads_controller.rb
@@ -1,19 +1,34 @@
 class UploadsController < ApplicationController
   include UploadsActions
 
+  UnknownUploadModelError = Class.new(StandardError)
+
+  MODEL_CLASSES = {
+    "user"             => User,
+    "project"          => Project,
+    "note"             => Note,
+    "group"            => Group,
+    "appearance"       => Appearance,
+    "personal_snippet" => PersonalSnippet,
+    nil                => PersonalSnippet
+  }.freeze
+
+  rescue_from UnknownUploadModelError, with: :render_404
+
   skip_before_action :authenticate_user!
+  before_action :upload_mount_satisfied?
   before_action :find_model
   before_action :authorize_access!, only: [:show]
   before_action :authorize_create_access!, only: [:create]
 
-  private
+  def uploader_class
+    PersonalFileUploader
+  end
 
   def find_model
     return nil unless params[:id]
 
-    return render_404 unless upload_model && upload_mount
-
-    @model = upload_model.find(params[:id])
+    upload_model_class.find(params[:id])
   end
 
   def authorize_access!
@@ -53,55 +68,17 @@ class UploadsController < ApplicationController
     end
   end
 
-  def upload_model
-    upload_models = {
-      "user"    => User,
-      "project" => Project,
-      "note"    => Note,
-      "group"   => Group,
-      "appearance" => Appearance,
-      "personal_snippet" => PersonalSnippet
-    }
-
-    upload_models[params[:model]]
-  end
-
-  def upload_mount
-    return true unless params[:mounted_as]
-
-    upload_mounts = %w(avatar attachment file logo header_logo)
-
-    if upload_mounts.include?(params[:mounted_as])
-      params[:mounted_as]
-    end
+  def upload_model_class
+    MODEL_CLASSES[params[:model]] || raise(UnknownUploadModelError)
   end
 
-  def uploader
-    return @uploader if defined?(@uploader)
-
-    case model
-    when nil
-      @uploader = PersonalFileUploader.new(nil, params[:secret])
-
-      @uploader.retrieve_from_store!(params[:filename])
-    when PersonalSnippet
-      @uploader = PersonalFileUploader.new(model, params[:secret])
-
-      @uploader.retrieve_from_store!(params[:filename])
-    else
-      @uploader = @model.public_send(upload_mount) # rubocop:disable GitlabSecurity/PublicSend
-
-      redirect_to @uploader.url unless @uploader.file_storage?
-    end
-
-    @uploader
+  def upload_model_class_has_mounts?
+    upload_model_class < CarrierWave::Mount::Extension
   end
 
-  def uploader_class
-    PersonalFileUploader
-  end
+  def upload_mount_satisfied?
+    return true unless upload_model_class_has_mounts?
 
-  def model
-    @model ||= find_model
+    upload_model_class.uploader_options.has_key?(upload_mount)
   end
 end
diff --git a/app/controllers/user_callouts_controller.rb b/app/controllers/user_callouts_controller.rb
new file mode 100644
index 00000000000..18cde4a7b1a
--- /dev/null
+++ b/app/controllers/user_callouts_controller.rb
@@ -0,0 +1,23 @@
+class UserCalloutsController < ApplicationController
+  def create
+    if ensure_callout.persisted?
+      respond_to do |format|
+        format.json { head :ok }
+      end
+    else
+      respond_to do |format|
+        format.json { head :bad_request }
+      end
+    end
+  end
+
+  private
+
+  def ensure_callout
+    current_user.callouts.find_or_create_by(feature_name: UserCallout.feature_names[feature_name])
+  end
+
+  def feature_name
+    params.require(:feature_name)
+  end
+end