Added Cop to blacklist the use of serialize

This Cop blacklists the use of ActiveRecord's "serialize" method, except
for cases where we already use this.

18 files changed, 85 insertions, 27 deletions

diff --git a/app/models/application_setting.rb b/app/models/application_setting.rb
index 043f57241a3..3d12f3c306b 100644
--- a/app/models/application_setting.rb
+++ b/app/models/application_setting.rb
@@ -13,13 +13,13 @@ class ApplicationSetting < ActiveRecord::Base
                             [\r\n]          # any number of newline characters
                           }x
 
-  serialize :restricted_visibility_levels
-  serialize :import_sources
-  serialize :disabled_oauth_sign_in_sources, Array
-  serialize :domain_whitelist, Array
-  serialize :domain_blacklist, Array
-  serialize :repository_storages
-  serialize :sidekiq_throttling_queues, Array
+  serialize :restricted_visibility_levels # rubocop:disable Cop/ActiverecordSerialize
+  serialize :import_sources # rubocop:disable Cop/ActiverecordSerialize
+  serialize :disabled_oauth_sign_in_sources, Array # rubocop:disable Cop/ActiverecordSerialize
+  serialize :domain_whitelist, Array # rubocop:disable Cop/ActiverecordSerialize
+  serialize :domain_blacklist, Array # rubocop:disable Cop/ActiverecordSerialize
+  serialize :repository_storages # rubocop:disable Cop/ActiverecordSerialize
+  serialize :sidekiq_throttling_queues, Array # rubocop:disable Cop/ActiverecordSerialize
 
   cache_markdown_field :sign_in_text
   cache_markdown_field :help_page_text
diff --git a/app/models/audit_event.rb b/app/models/audit_event.rb
index 967ffd46db0..46d412fbd72 100644
--- a/app/models/audit_event.rb
+++ b/app/models/audit_event.rb
@@ -1,5 +1,5 @@
 class AuditEvent < ActiveRecord::Base
-  serialize :details, Hash
+  serialize :details, Hash # rubocop:disable Cop/ActiverecordSerialize
 
   belongs_to :user, foreign_key: :author_id
 
diff --git a/app/models/ci/build.rb b/app/models/ci/build.rb
index 760ec8e5919..38ee5225387 100644
--- a/app/models/ci/build.rb
+++ b/app/models/ci/build.rb
@@ -19,8 +19,8 @@ module Ci
       )
     end
 
-    serialize :options
-    serialize :yaml_variables, Gitlab::Serializer::Ci::Variables
+    serialize :options # rubocop:disable Cop/ActiverecordSerialize
+    serialize :yaml_variables, Gitlab::Serializer::Ci::Variables # rubocop:disable Cop/ActiverecordSerialize
 
     delegate :name, to: :project, prefix: true
 
diff --git a/app/models/ci/trigger_request.rb b/app/models/ci/trigger_request.rb
index 2b807731d0d..564334ad1ad 100644
--- a/app/models/ci/trigger_request.rb
+++ b/app/models/ci/trigger_request.rb
@@ -6,7 +6,7 @@ module Ci
     belongs_to :pipeline, foreign_key: :commit_id
     has_many :builds
 
-    serialize :variables
+    serialize :variables # rubocop:disable Cop/ActiverecordSerialize
 
     def user_variables
       return [] unless variables
diff --git a/app/models/diff_note.rb b/app/models/diff_note.rb
index 2a4cff37566..6cd0502069a 100644
--- a/app/models/diff_note.rb
+++ b/app/models/diff_note.rb
@@ -6,9 +6,9 @@ class DiffNote < Note
 
   NOTEABLE_TYPES = %w(MergeRequest Commit).freeze
 
-  serialize :original_position, Gitlab::Diff::Position
-  serialize :position, Gitlab::Diff::Position
-  serialize :change_position, Gitlab::Diff::Position
+  serialize :original_position, Gitlab::Diff::Position # rubocop:disable Cop/ActiverecordSerialize
+  serialize :position, Gitlab::Diff::Position # rubocop:disable Cop/ActiverecordSerialize
+  serialize :change_position, Gitlab::Diff::Position # rubocop:disable Cop/ActiverecordSerialize
 
   validates :original_position, presence: true
   validates :position, presence: true
diff --git a/app/models/event.rb b/app/models/event.rb
index e6fad46077a..46e89388bc1 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -26,7 +26,7 @@ class Event < ActiveRecord::Base
   belongs_to :target, polymorphic: true
 
   # For Hash only
-  serialize :data
+  serialize :data # rubocop:disable Cop/ActiverecordSerialize
 
   # Callbacks
   after_create :reset_project_activity
diff --git a/app/models/hooks/web_hook_log.rb b/app/models/hooks/web_hook_log.rb
index 2738b229d84..d73cfcf630d 100644
--- a/app/models/hooks/web_hook_log.rb
+++ b/app/models/hooks/web_hook_log.rb
@@ -1,9 +1,9 @@
 class WebHookLog < ActiveRecord::Base
   belongs_to :web_hook
 
-  serialize :request_headers, Hash
-  serialize :request_data, Hash
-  serialize :response_headers, Hash
+  serialize :request_headers, Hash # rubocop:disable Cop/ActiverecordSerialize
+  serialize :request_data, Hash # rubocop:disable Cop/ActiverecordSerialize
+  serialize :response_headers, Hash # rubocop:disable Cop/ActiverecordSerialize
 
   validates :web_hook, presence: true
 
diff --git a/app/models/legacy_diff_note.rb b/app/models/legacy_diff_note.rb
index ebf8fb92ab5..7126de2d488 100644
--- a/app/models/legacy_diff_note.rb
+++ b/app/models/legacy_diff_note.rb
@@ -7,7 +7,7 @@
 class LegacyDiffNote < Note
   include NoteOnDiff
 
-  serialize :st_diff
+  serialize :st_diff # rubocop:disable Cop/ActiverecordSerialize
 
   validates :line_code, presence: true, line_code: true
 
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 356af776b8d..994bd3ce19a 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -21,7 +21,7 @@ class MergeRequest < ActiveRecord::Base
 
   belongs_to :assignee, class_name: "User"
 
-  serialize :merge_params, Hash
+  serialize :merge_params, Hash # rubocop:disable Cop/ActiverecordSerialize
 
   after_create :ensure_merge_request_diff, unless: :importing?
   after_update :reload_diff_if_branch_changed
diff --git a/app/models/merge_request_diff.rb b/app/models/merge_request_diff.rb
index 1bd61c1d465..1c2f335f95e 100644
--- a/app/models/merge_request_diff.rb
+++ b/app/models/merge_request_diff.rb
@@ -11,8 +11,8 @@ class MergeRequestDiff < ActiveRecord::Base
 
   belongs_to :merge_request
 
-  serialize :st_commits
-  serialize :st_diffs
+  serialize :st_commits # rubocop:disable Cop/ActiverecordSerialize
+  serialize :st_diffs # rubocop:disable Cop/ActiverecordSerialize
 
   state_machine :state, initial: :empty do
     state :collected
diff --git a/app/models/personal_access_token.rb b/app/models/personal_access_token.rb
index e8b000ddad6..ae9f71e7747 100644
--- a/app/models/personal_access_token.rb
+++ b/app/models/personal_access_token.rb
@@ -3,7 +3,7 @@ class PersonalAccessToken < ActiveRecord::Base
   include TokenAuthenticatable
   add_authentication_token_field :token
 
-  serialize :scopes, Array
+  serialize :scopes, Array # rubocop:disable Cop/ActiverecordSerialize
 
   belongs_to :user
 
diff --git a/app/models/project_import_data.rb b/app/models/project_import_data.rb
index 331123a5a5b..e3cafd4d1c6 100644
--- a/app/models/project_import_data.rb
+++ b/app/models/project_import_data.rb
@@ -10,7 +10,7 @@ class ProjectImportData < ActiveRecord::Base
                  insecure_mode: true,
                  algorithm: 'aes-256-cbc'
 
-  serialize :data, JSON
+  serialize :data, JSON # rubocop:disable Cop/ActiverecordSerialize
 
   validates :project, presence: true
 
diff --git a/app/models/sent_notification.rb b/app/models/sent_notification.rb
index 0ae5864615a..eed3ca7e179 100644
--- a/app/models/sent_notification.rb
+++ b/app/models/sent_notification.rb
@@ -1,5 +1,5 @@
 class SentNotification < ActiveRecord::Base
-  serialize :position, Gitlab::Diff::Position
+  serialize :position, Gitlab::Diff::Position # rubocop:disable Cop/ActiverecordSerialize
 
   belongs_to :project
   belongs_to :noteable, polymorphic: true
diff --git a/app/models/service.rb b/app/models/service.rb
index 8916f88076e..6a0b0a5c522 100644
--- a/app/models/service.rb
+++ b/app/models/service.rb
@@ -2,7 +2,7 @@
 # and implement a set of methods
 class Service < ActiveRecord::Base
   include Sortable
-  serialize :properties, JSON
+  serialize :properties, JSON # rubocop:disable Cop/ActiverecordSerialize
 
   default_value_for :active, false
   default_value_for :push_events, true
diff --git a/app/models/user.rb b/app/models/user.rb
index 3f816a250c2..35dca105dc0 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -40,7 +40,7 @@ class User < ActiveRecord::Base
          otp_secret_encryption_key: Gitlab::Application.secrets.otp_key_base
 
   devise :two_factor_backupable, otp_number_of_backup_codes: 10
-  serialize :otp_backup_codes, JSON
+  serialize :otp_backup_codes, JSON # rubocop:disable Cop/ActiverecordSerialize
 
   devise :lockable, :recoverable, :rememberable, :trackable,
     :validatable, :omniauthable, :confirmable, :registerable
diff --git a/rubocop/cop/activerecord_serialize.rb b/rubocop/cop/activerecord_serialize.rb
new file mode 100644
index 00000000000..bfa0cff9a67
--- /dev/null
+++ b/rubocop/cop/activerecord_serialize.rb
@@ -0,0 +1,24 @@
+module RuboCop
+  module Cop
+    # Cop that prevents the use of `serialize` in ActiveRecord models.
+    class ActiverecordSerialize < RuboCop::Cop::Cop
+      MSG = 'Do not store serialized data in the database, use separate columns and/or tables instead'.freeze
+
+      def on_send(node)
+        return unless in_models?(node)
+
+        add_offense(node, :selector) if node.children[1] == :serialize
+      end
+
+      def models_path
+        File.join(Dir.pwd, 'app', 'models')
+      end
+
+      def in_models?(node)
+        path = node.location.expression.source_buffer.name
+
+        path.start_with?(models_path)
+      end
+    end
+  end
+end
diff --git a/rubocop/rubocop.rb b/rubocop/rubocop.rb
index b65efbc41f4..17d2bf6aa1c 100644
--- a/rubocop/rubocop.rb
+++ b/rubocop/rubocop.rb
@@ -1,5 +1,6 @@
 require_relative 'cop/custom_error_class'
 require_relative 'cop/gem_fetcher'
+require_relative 'cop/activerecord_serialize'
 require_relative 'cop/migration/add_column'
 require_relative 'cop/migration/add_column_with_default_to_large_table'
 require_relative 'cop/migration/add_concurrent_foreign_key'
diff --git a/spec/rubocop/cop/activerecord_serialize_spec.rb b/spec/rubocop/cop/activerecord_serialize_spec.rb
new file mode 100644
index 00000000000..a303b16d264
--- /dev/null
+++ b/spec/rubocop/cop/activerecord_serialize_spec.rb
@@ -0,0 +1,33 @@
+require 'spec_helper'
+require 'rubocop'
+require 'rubocop/rspec/support'
+require_relative '../../../rubocop/cop/activerecord_serialize'
+
+describe RuboCop::Cop::ActiverecordSerialize do
+  include CopHelper
+
+  subject(:cop) { described_class.new }
+
+  context 'inside the app/models directory' do
+    it 'registers an offense when serialize is used' do
+      allow(cop).to receive(:in_models?).and_return(true)
+
+      inspect_source(cop, 'serialize :foo')
+
+      aggregate_failures do
+        expect(cop.offenses.size).to eq(1)
+        expect(cop.offenses.map(&:line)).to eq([1])
+      end
+    end
+  end
+
+  context 'outside the app/models directory' do
+    it 'does nothing' do
+      allow(cop).to receive(:in_models?).and_return(false)
+
+      inspect_source(cop, 'serialize :foo')
+
+      expect(cop.offenses).to be_empty
+    end
+  end
+end