Adds cop to enforce string limits on migrations

This cop will analyze migrations that add columns with string, and
report an offense if the string has no limit enforced

Related to https://gitlab.com/gitlab-org/gitlab-ce/issues/64505

73 files changed, 431 insertions, 51 deletions

diff --git a/db/migrate/20171230123729_init_schema.rb b/db/migrate/20171230123729_init_schema.rb
index fa90b37954f..a474ea2f925 100644
--- a/db/migrate/20171230123729_init_schema.rb
+++ b/db/migrate/20171230123729_init_schema.rb
@@ -5,6 +5,7 @@
 # rubocop:disable Metrics/AbcSize
 # rubocop:disable Migration/AddConcurrentForeignKey
 # rubocop:disable Style/WordArray
+# rubocop:disable Migration/AddLimitToStringColumns
 
 class InitSchema < ActiveRecord::Migration[4.2]
   DOWNTIME = false
@@ -1852,3 +1853,4 @@ class InitSchema < ActiveRecord::Migration[4.2]
     raise ActiveRecord::IrreversibleMigration, "The initial migration is not revertable"
   end
 end
+# rubocop:enable Migration/AddLimitToStringColumns
diff --git a/db/migrate/20180101160629_create_prometheus_metrics.rb b/db/migrate/20180101160629_create_prometheus_metrics.rb
index e3b1ed710d6..a098b999a0a 100644
--- a/db/migrate/20180101160629_create_prometheus_metrics.rb
+++ b/db/migrate/20180101160629_create_prometheus_metrics.rb
@@ -4,6 +4,7 @@ class CreatePrometheusMetrics < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :prometheus_metrics do |t|
       t.references :project, index: true, foreign_key: { on_delete: :cascade }, null: false
       t.string :title, null: false
@@ -14,5 +15,6 @@ class CreatePrometheusMetrics < ActiveRecord::Migration[4.2]
       t.integer :group, null: false, index: true
       t.timestamps_with_timezone null: false
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180122162010_add_auto_devops_domain_to_application_settings.rb b/db/migrate/20180122162010_add_auto_devops_domain_to_application_settings.rb
index c76dc5b3a68..eb446ad0d72 100644
--- a/db/migrate/20180122162010_add_auto_devops_domain_to_application_settings.rb
+++ b/db/migrate/20180122162010_add_auto_devops_domain_to_application_settings.rb
@@ -8,6 +8,6 @@ class AddAutoDevopsDomainToApplicationSettings < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
-    add_column :application_settings, :auto_devops_domain, :string
+    add_column :application_settings, :auto_devops_domain, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180129193323_add_uploads_builder_context.rb b/db/migrate/20180129193323_add_uploads_builder_context.rb
index c7227bf0f1e..710fa7b3ba8 100644
--- a/db/migrate/20180129193323_add_uploads_builder_context.rb
+++ b/db/migrate/20180129193323_add_uploads_builder_context.rb
@@ -8,7 +8,9 @@ class AddUploadsBuilderContext < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     add_column :uploads, :mount_point, :string
     add_column :uploads, :secret, :string
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180212030105_add_external_ip_to_clusters_applications_ingress.rb b/db/migrate/20180212030105_add_external_ip_to_clusters_applications_ingress.rb
index e2a9a68b1ad..78aa2014601 100644
--- a/db/migrate/20180212030105_add_external_ip_to_clusters_applications_ingress.rb
+++ b/db/migrate/20180212030105_add_external_ip_to_clusters_applications_ingress.rb
@@ -4,6 +4,6 @@ class AddExternalIpToClustersApplicationsIngress < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
-    add_column :clusters_applications_ingress, :external_ip, :string
+    add_column :clusters_applications_ingress, :external_ip, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180214093516_create_badges.rb b/db/migrate/20180214093516_create_badges.rb
index 66e017b115a..fe27d465571 100644
--- a/db/migrate/20180214093516_create_badges.rb
+++ b/db/migrate/20180214093516_create_badges.rb
@@ -2,6 +2,7 @@ class CreateBadges < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :badges do |t|
       t.string     :link_url, null: false
       t.string     :image_url, null: false
@@ -11,6 +12,7 @@ class CreateBadges < ActiveRecord::Migration[4.2]
 
       t.timestamps_with_timezone null: false
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
 
     # rubocop:disable Migration/AddConcurrentForeignKey
     add_foreign_key :badges, :namespaces, column: :group_id, on_delete: :cascade
diff --git a/db/migrate/20180214155405_create_clusters_applications_runners.rb b/db/migrate/20180214155405_create_clusters_applications_runners.rb
index ce594c91890..f611fefbb0d 100644
--- a/db/migrate/20180214155405_create_clusters_applications_runners.rb
+++ b/db/migrate/20180214155405_create_clusters_applications_runners.rb
@@ -13,7 +13,7 @@ class CreateClustersApplicationsRunners < ActiveRecord::Migration[4.2]
       t.index :cluster_id, unique: true
       t.integer :status, null: false
       t.timestamps_with_timezone null: false
-      t.string :version, null: false
+      t.string :version, null: false # rubocop:disable Migration/AddLimitToStringColumns
       t.text :status_reason
     end
 
diff --git a/db/migrate/20180216120000_add_pages_domain_verification.rb b/db/migrate/20180216120000_add_pages_domain_verification.rb
index f709f5a5809..b2f19f2e1a9 100644
--- a/db/migrate/20180216120000_add_pages_domain_verification.rb
+++ b/db/migrate/20180216120000_add_pages_domain_verification.rb
@@ -3,6 +3,6 @@ class AddPagesDomainVerification < ActiveRecord::Migration[4.2]
 
   def change
     add_column :pages_domains, :verified_at, :datetime_with_timezone
-    add_column :pages_domains, :verification_code, :string
+    add_column :pages_domains, :verification_code, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180222043024_add_ip_address_to_runner.rb b/db/migrate/20180222043024_add_ip_address_to_runner.rb
index b52366c0be1..08fb0bd900c 100644
--- a/db/migrate/20180222043024_add_ip_address_to_runner.rb
+++ b/db/migrate/20180222043024_add_ip_address_to_runner.rb
@@ -4,6 +4,6 @@ class AddIpAddressToRunner < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
-    add_column :ci_runners, :ip_address, :string
+    add_column :ci_runners, :ip_address, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180308125206_add_user_internal_regex_to_application_setting.rb b/db/migrate/20180308125206_add_user_internal_regex_to_application_setting.rb
index 5e4bf96f86f..9bdd44baf58 100644
--- a/db/migrate/20180308125206_add_user_internal_regex_to_application_setting.rb
+++ b/db/migrate/20180308125206_add_user_internal_regex_to_application_setting.rb
@@ -4,7 +4,7 @@ class AddUserInternalRegexToApplicationSetting < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def up
-    add_column :application_settings, :user_default_internal_regex, :string, null: true
+    add_column :application_settings, :user_default_internal_regex, :string, null: true # rubocop:disable Migration/AddLimitToStringColumns
   end
 
   def down
diff --git a/db/migrate/20180315160435_add_external_auth_mutual_tls_fields_to_project_settings.rb b/db/migrate/20180315160435_add_external_auth_mutual_tls_fields_to_project_settings.rb
index ee3d1078f5e..c379d207ff0 100644
--- a/db/migrate/20180315160435_add_external_auth_mutual_tls_fields_to_project_settings.rb
+++ b/db/migrate/20180315160435_add_external_auth_mutual_tls_fields_to_project_settings.rb
@@ -2,6 +2,7 @@ class AddExternalAuthMutualTlsFieldsToProjectSettings < ActiveRecord::Migration[
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     add_column :application_settings,
                :external_auth_client_cert, :text
     add_column :application_settings,
@@ -12,5 +13,6 @@ class AddExternalAuthMutualTlsFieldsToProjectSettings < ActiveRecord::Migration[
                :encrypted_external_auth_client_key_pass, :string
     add_column :application_settings,
                :encrypted_external_auth_client_key_pass_iv, :string
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180319190020_create_deploy_tokens.rb b/db/migrate/20180319190020_create_deploy_tokens.rb
index a4d797679c5..f444521b3ae 100644
--- a/db/migrate/20180319190020_create_deploy_tokens.rb
+++ b/db/migrate/20180319190020_create_deploy_tokens.rb
@@ -2,6 +2,7 @@ class CreateDeployTokens < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :deploy_tokens do |t|
       t.boolean :revoked, default: false
       t.boolean :read_repository, null: false, default: false
@@ -15,5 +16,6 @@ class CreateDeployTokens < ActiveRecord::Migration[4.2]
 
       t.index [:token, :expires_at, :id], where: "(revoked IS FALSE)"
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180502122856_create_project_mirror_data.rb b/db/migrate/20180502122856_create_project_mirror_data.rb
index 9781815a97b..04367e1c98b 100644
--- a/db/migrate/20180502122856_create_project_mirror_data.rb
+++ b/db/migrate/20180502122856_create_project_mirror_data.rb
@@ -3,6 +3,7 @@ class CreateProjectMirrorData < ActiveRecord::Migration[4.2]
 
   DOWNTIME = false
 
+  # rubocop:disable Migration/AddLimitToStringColumns
   def up
     if table_exists?(:project_mirror_data)
       add_column :project_mirror_data, :status, :string unless column_exists?(:project_mirror_data, :status)
@@ -17,6 +18,7 @@ class CreateProjectMirrorData < ActiveRecord::Migration[4.2]
       end
     end
   end
+  # rubocop:enable Migration/AddLimitToStringColumns
 
   def down
     remove_column :project_mirror_data, :status
diff --git a/db/migrate/20180503131624_create_remote_mirrors.rb b/db/migrate/20180503131624_create_remote_mirrors.rb
index 288ae365f0f..a079c1b3328 100644
--- a/db/migrate/20180503131624_create_remote_mirrors.rb
+++ b/db/migrate/20180503131624_create_remote_mirrors.rb
@@ -5,6 +5,7 @@ class CreateRemoteMirrors < ActiveRecord::Migration[4.2]
 
   disable_ddl_transaction!
 
+  # rubocop:disable Migration/AddLimitToStringColumns
   def up
     return if table_exists?(:remote_mirrors)
 
@@ -27,6 +28,7 @@ class CreateRemoteMirrors < ActiveRecord::Migration[4.2]
       t.timestamps null: false
     end
   end
+  # rubocop:enable Migration/AddLimitToStringColumns
 
   def down
     # ee/db/migrate/20160321161032_create_remote_mirrors_ee.rb will remove the table
diff --git a/db/migrate/20180503175053_ensure_missing_columns_to_project_mirror_data.rb b/db/migrate/20180503175053_ensure_missing_columns_to_project_mirror_data.rb
index 3775b3a08c9..f00493ed515 100644
--- a/db/migrate/20180503175053_ensure_missing_columns_to_project_mirror_data.rb
+++ b/db/migrate/20180503175053_ensure_missing_columns_to_project_mirror_data.rb
@@ -4,8 +4,8 @@ class EnsureMissingColumnsToProjectMirrorData < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def up
-    add_column :project_mirror_data, :status, :string unless column_exists?(:project_mirror_data, :status)
-    add_column :project_mirror_data, :jid, :string unless column_exists?(:project_mirror_data, :jid)
+    add_column :project_mirror_data, :status, :string unless column_exists?(:project_mirror_data, :status) # rubocop:disable Migration/AddLimitToStringColumns
+    add_column :project_mirror_data, :jid, :string unless column_exists?(:project_mirror_data, :jid) # rubocop:disable Migration/AddLimitToStringColumns
     add_column :project_mirror_data, :last_error, :text unless column_exists?(:project_mirror_data, :last_error)
   end
 
diff --git a/db/migrate/20180511131058_create_clusters_applications_jupyter.rb b/db/migrate/20180511131058_create_clusters_applications_jupyter.rb
index 749aeeb4792..4633d930e2d 100644
--- a/db/migrate/20180511131058_create_clusters_applications_jupyter.rb
+++ b/db/migrate/20180511131058_create_clusters_applications_jupyter.rb
@@ -7,17 +7,19 @@ class CreateClustersApplicationsJupyter < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :clusters_applications_jupyter do |t|
       t.references :cluster, null: false, unique: true, foreign_key: { on_delete: :cascade }
       t.references :oauth_application, foreign_key: { on_delete: :nullify }
 
       t.integer :status, null: false
-      t.string :version, null: false
-      t.string :hostname
+      t.string :version, null: false # rubocop:disable Migration/AddLimitToStringColumns
+      t.string :hostname # rubocop:disable Migration/AddLimitToStringColumns
 
       t.timestamps_with_timezone null: false
 
       t.text :status_reason
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180515121227_create_notes_diff_files.rb b/db/migrate/20180515121227_create_notes_diff_files.rb
index e50324d8599..5f6dba11ff9 100644
--- a/db/migrate/20180515121227_create_notes_diff_files.rb
+++ b/db/migrate/20180515121227_create_notes_diff_files.rb
@@ -4,6 +4,7 @@ class CreateNotesDiffFiles < ActiveRecord::Migration[4.2]
   disable_ddl_transaction!
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :note_diff_files do |t|
       t.references :diff_note, references: :notes, null: false, index: { unique: true }
       t.text :diff, null: false
@@ -18,5 +19,6 @@ class CreateNotesDiffFiles < ActiveRecord::Migration[4.2]
 
     # rubocop:disable Migration/AddConcurrentForeignKey
     add_foreign_key :note_diff_files, :notes, column: :diff_note_id, on_delete: :cascade
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180529093006_ensure_remote_mirror_columns.rb b/db/migrate/20180529093006_ensure_remote_mirror_columns.rb
index 207e1f089fb..a0a1150f022 100644
--- a/db/migrate/20180529093006_ensure_remote_mirror_columns.rb
+++ b/db/migrate/20180529093006_ensure_remote_mirror_columns.rb
@@ -8,7 +8,7 @@ class EnsureRemoteMirrorColumns < ActiveRecord::Migration[4.2]
   def up
     # rubocop:disable Migration/Datetime
     add_column :remote_mirrors, :last_update_started_at, :datetime unless column_exists?(:remote_mirrors, :last_update_started_at)
-    add_column :remote_mirrors, :remote_name, :string unless column_exists?(:remote_mirrors, :remote_name)
+    add_column :remote_mirrors, :remote_name, :string unless column_exists?(:remote_mirrors, :remote_name) # rubocop:disable Migration/AddLimitToStringColumns
 
     unless column_exists?(:remote_mirrors, :only_protected_branches)
       add_column_with_default(:remote_mirrors,
diff --git a/db/migrate/20180531185349_add_repository_languages.rb b/db/migrate/20180531185349_add_repository_languages.rb
index 26a01c3bb26..d517c21c26c 100644
--- a/db/migrate/20180531185349_add_repository_languages.rb
+++ b/db/migrate/20180531185349_add_repository_languages.rb
@@ -4,6 +4,7 @@ class AddRepositoryLanguages < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def up
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table(:programming_languages) do |t|
       t.string :name, null: false
       t.string :color, null: false
@@ -19,6 +20,7 @@ class AddRepositoryLanguages < ActiveRecord::Migration[4.2]
     add_index :programming_languages, :name, unique: true
     add_index :repository_languages, [:project_id, :programming_language_id],
       unique: true, name: "index_repository_languages_on_project_and_languages_id"
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 
   def down
diff --git a/db/migrate/20180613081317_create_ci_builds_runner_session.rb b/db/migrate/20180613081317_create_ci_builds_runner_session.rb
index eb41f76b105..68af38834d2 100644
--- a/db/migrate/20180613081317_create_ci_builds_runner_session.rb
+++ b/db/migrate/20180613081317_create_ci_builds_runner_session.rb
@@ -8,6 +8,7 @@ class CreateCiBuildsRunnerSession < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :ci_builds_runner_session, id: :bigserial do |t|
       t.integer :build_id, null: false
       t.string :url, null: false
@@ -17,5 +18,6 @@ class CreateCiBuildsRunnerSession < ActiveRecord::Migration[4.2]
       t.foreign_key :ci_builds, column: :build_id, on_delete: :cascade
       t.index :build_id, unique: true
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180713092803_create_user_statuses.rb b/db/migrate/20180713092803_create_user_statuses.rb
index 43b96805c1e..3abab4e45a9 100644
--- a/db/migrate/20180713092803_create_user_statuses.rb
+++ b/db/migrate/20180713092803_create_user_statuses.rb
@@ -6,6 +6,7 @@ class CreateUserStatuses < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :user_statuses, id: false, primary_key: :user_id do |t|
       t.references :user,
                    foreign_key: { on_delete: :cascade },
@@ -16,5 +17,6 @@ class CreateUserStatuses < ActiveRecord::Migration[4.2]
       t.string :message, limit: 100
       t.string :message_html
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180814153625_add_commit_email_to_users.rb b/db/migrate/20180814153625_add_commit_email_to_users.rb
index 4d9217ea504..98bafc14a03 100644
--- a/db/migrate/20180814153625_add_commit_email_to_users.rb
+++ b/db/migrate/20180814153625_add_commit_email_to_users.rb
@@ -28,6 +28,6 @@ class AddCommitEmailToUsers < ActiveRecord::Migration[4.2]
   # disable_ddl_transaction!
 
   def change
-    add_column :users, :commit_email, :string
+    add_column :users, :commit_email, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180831164908_add_identifier_to_prometheus_metric.rb b/db/migrate/20180831164908_add_identifier_to_prometheus_metric.rb
index 7aa5950249c..8f30363c310 100644
--- a/db/migrate/20180831164908_add_identifier_to_prometheus_metric.rb
+++ b/db/migrate/20180831164908_add_identifier_to_prometheus_metric.rb
@@ -6,6 +6,6 @@ class AddIdentifierToPrometheusMetric < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
-    add_column :prometheus_metrics, :identifier, :string
+    add_column :prometheus_metrics, :identifier, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180910115836_add_attr_encrypted_columns_to_web_hook.rb b/db/migrate/20180910115836_add_attr_encrypted_columns_to_web_hook.rb
index ca8dbdba2bb..9757f7fdc79 100644
--- a/db/migrate/20180910115836_add_attr_encrypted_columns_to_web_hook.rb
+++ b/db/migrate/20180910115836_add_attr_encrypted_columns_to_web_hook.rb
@@ -6,10 +6,12 @@ class AddAttrEncryptedColumnsToWebHook < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     add_column :web_hooks, :encrypted_token, :string
     add_column :web_hooks, :encrypted_token_iv, :string
 
     add_column :web_hooks, :encrypted_url, :string
     add_column :web_hooks, :encrypted_url_iv, :string
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20180910153412_add_token_digest_to_personal_access_tokens.rb b/db/migrate/20180910153412_add_token_digest_to_personal_access_tokens.rb
index 142e454832f..52923f52499 100644
--- a/db/migrate/20180910153412_add_token_digest_to_personal_access_tokens.rb
+++ b/db/migrate/20180910153412_add_token_digest_to_personal_access_tokens.rb
@@ -8,7 +8,7 @@ class AddTokenDigestToPersonalAccessTokens < ActiveRecord::Migration[4.2]
   def up
     change_column :personal_access_tokens, :token, :string, null: true
 
-    add_column :personal_access_tokens, :token_digest, :string
+    add_column :personal_access_tokens, :token_digest, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 
   def down
diff --git a/db/migrate/20180912111628_add_knative_application.rb b/db/migrate/20180912111628_add_knative_application.rb
index 86d9100d2e7..7c55de02d1c 100644
--- a/db/migrate/20180912111628_add_knative_application.rb
+++ b/db/migrate/20180912111628_add_knative_application.rb
@@ -6,6 +6,7 @@ class AddKnativeApplication < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table "clusters_applications_knative" do |t|
       t.references :cluster, null: false, unique: true, foreign_key: { on_delete: :cascade }
 
@@ -16,5 +17,6 @@ class AddKnativeApplication < ActiveRecord::Migration[4.2]
       t.string "hostname"
       t.text "status_reason"
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181009190428_create_clusters_kubernetes_namespaces.rb b/db/migrate/20181009190428_create_clusters_kubernetes_namespaces.rb
index 62ad6c63d0a..b6ffb2866aa 100644
--- a/db/migrate/20181009190428_create_clusters_kubernetes_namespaces.rb
+++ b/db/migrate/20181009190428_create_clusters_kubernetes_namespaces.rb
@@ -5,6 +5,7 @@ class CreateClustersKubernetesNamespaces < ActiveRecord::Migration[4.2]
   INDEX_NAME = 'kubernetes_namespaces_cluster_and_namespace'
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :clusters_kubernetes_namespaces, id: :bigserial do |t|
       t.references :cluster, null: false, index: true, foreign_key: { on_delete: :cascade }
       t.references :project, index: true, foreign_key: { on_delete: :nullify }
@@ -20,5 +21,6 @@ class CreateClustersKubernetesNamespaces < ActiveRecord::Migration[4.2]
 
       t.index [:cluster_id, :namespace], name: INDEX_NAME, unique: true
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181019032400_add_shards_table.rb b/db/migrate/20181019032400_add_shards_table.rb
index e31af97cc94..82287e5c3b5 100644
--- a/db/migrate/20181019032400_add_shards_table.rb
+++ b/db/migrate/20181019032400_add_shards_table.rb
@@ -5,7 +5,7 @@ class AddShardsTable < ActiveRecord::Migration[4.2]
 
   def change
     create_table :shards do |t|
-      t.string :name, null: false, index: { unique: true }
+      t.string :name, null: false, index: { unique: true } # rubocop:disable Migration/AddLimitToStringColumns
     end
   end
 end
diff --git a/db/migrate/20181019032408_add_repositories_table.rb b/db/migrate/20181019032408_add_repositories_table.rb
index 2153c1c9fc6..dd510b44084 100644
--- a/db/migrate/20181019032408_add_repositories_table.rb
+++ b/db/migrate/20181019032408_add_repositories_table.rb
@@ -6,7 +6,7 @@ class AddRepositoriesTable < ActiveRecord::Migration[4.2]
   def change
     create_table :repositories, id: :bigserial do |t|
       t.references :shard, null: false, index: true, foreign_key: { on_delete: :restrict }
-      t.string :disk_path, null: false, index: { unique: true }
+      t.string :disk_path, null: false, index: { unique: true } # rubocop:disable Migration/AddLimitToStringColumns
     end
 
     add_column :projects, :pool_repository_id, :bigint
diff --git a/db/migrate/20181025115728_add_private_commit_email_hostname_to_application_settings.rb b/db/migrate/20181025115728_add_private_commit_email_hostname_to_application_settings.rb
index 052a344f182..c0e4897b8d7 100644
--- a/db/migrate/20181025115728_add_private_commit_email_hostname_to_application_settings.rb
+++ b/db/migrate/20181025115728_add_private_commit_email_hostname_to_application_settings.rb
@@ -6,6 +6,6 @@ class AddPrivateCommitEmailHostnameToApplicationSettings < ActiveRecord::Migrati
   DOWNTIME = false
 
   def change
-    add_column(:application_settings, :commit_email_hostname, :string, null: true)
+    add_column(:application_settings, :commit_email_hostname, :string, null: true) # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181031190559_drop_gcp_clusters_table.rb b/db/migrate/20181031190559_drop_gcp_clusters_table.rb
index 597fe49f4c8..850fa93c75a 100644
--- a/db/migrate/20181031190559_drop_gcp_clusters_table.rb
+++ b/db/migrate/20181031190559_drop_gcp_clusters_table.rb
@@ -10,6 +10,7 @@ class DropGcpClustersTable < ActiveRecord::Migration[4.2]
   end
 
   def down
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :gcp_clusters do |t|
       # Order columns by best align scheme
       t.references :project, null: false, index: { unique: true }, foreign_key: { on_delete: :cascade }
@@ -49,5 +50,6 @@ class DropGcpClustersTable < ActiveRecord::Migration[4.2]
       t.text :encrypted_gcp_token
       t.string :encrypted_gcp_token_iv
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181101191341_create_clusters_applications_cert_manager.rb b/db/migrate/20181101191341_create_clusters_applications_cert_manager.rb
index 0b6155356d9..3bc20046311 100644
--- a/db/migrate/20181101191341_create_clusters_applications_cert_manager.rb
+++ b/db/migrate/20181101191341_create_clusters_applications_cert_manager.rb
@@ -6,6 +6,7 @@ class CreateClustersApplicationsCertManager < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :clusters_applications_cert_managers do |t|
       t.references :cluster, null: false, index: false, foreign_key: { on_delete: :cascade }
       t.integer :status, null: false
@@ -15,5 +16,6 @@ class CreateClustersApplicationsCertManager < ActiveRecord::Migration[4.2]
       t.text :status_reason
       t.index :cluster_id, unique: true
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181115140140_add_encrypted_runners_token_to_settings.rb b/db/migrate/20181115140140_add_encrypted_runners_token_to_settings.rb
index 5b2bb4f6b08..124eedf7933 100644
--- a/db/migrate/20181115140140_add_encrypted_runners_token_to_settings.rb
+++ b/db/migrate/20181115140140_add_encrypted_runners_token_to_settings.rb
@@ -6,6 +6,6 @@ class AddEncryptedRunnersTokenToSettings < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
-    add_column :application_settings, :runners_registration_token_encrypted, :string
+    add_column :application_settings, :runners_registration_token_encrypted, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181116050532_knative_external_ip.rb b/db/migrate/20181116050532_knative_external_ip.rb
index 5645b040a23..4634b411108 100644
--- a/db/migrate/20181116050532_knative_external_ip.rb
+++ b/db/migrate/20181116050532_knative_external_ip.rb
@@ -9,6 +9,6 @@ class KnativeExternalIp < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
-    add_column :clusters_applications_knative, :external_ip, :string
+    add_column :clusters_applications_knative, :external_ip, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181116141415_add_encrypted_runners_token_to_namespaces.rb b/db/migrate/20181116141415_add_encrypted_runners_token_to_namespaces.rb
index dcf565cd6c0..0a8ed912891 100644
--- a/db/migrate/20181116141415_add_encrypted_runners_token_to_namespaces.rb
+++ b/db/migrate/20181116141415_add_encrypted_runners_token_to_namespaces.rb
@@ -6,6 +6,6 @@ class AddEncryptedRunnersTokenToNamespaces < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
-    add_column :namespaces, :runners_token_encrypted, :string
+    add_column :namespaces, :runners_token_encrypted, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181116141504_add_encrypted_runners_token_to_projects.rb b/db/migrate/20181116141504_add_encrypted_runners_token_to_projects.rb
index 13cd80e5c8b..3083dff49b8 100644
--- a/db/migrate/20181116141504_add_encrypted_runners_token_to_projects.rb
+++ b/db/migrate/20181116141504_add_encrypted_runners_token_to_projects.rb
@@ -6,6 +6,6 @@ class AddEncryptedRunnersTokenToProjects < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
-    add_column :projects, :runners_token_encrypted, :string
+    add_column :projects, :runners_token_encrypted, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181120151656_add_token_encrypted_to_ci_runners.rb b/db/migrate/20181120151656_add_token_encrypted_to_ci_runners.rb
index 8b990451adc..2270246dfb4 100644
--- a/db/migrate/20181120151656_add_token_encrypted_to_ci_runners.rb
+++ b/db/migrate/20181120151656_add_token_encrypted_to_ci_runners.rb
@@ -6,6 +6,6 @@ class AddTokenEncryptedToCiRunners < ActiveRecord::Migration[4.2]
   DOWNTIME = false
 
   def change
-    add_column :ci_runners, :token_encrypted, :string
+    add_column :ci_runners, :token_encrypted, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181122160027_create_project_repositories.rb b/db/migrate/20181122160027_create_project_repositories.rb
index e42cef9b1c6..3f123daa150 100644
--- a/db/migrate/20181122160027_create_project_repositories.rb
+++ b/db/migrate/20181122160027_create_project_repositories.rb
@@ -11,7 +11,7 @@ class CreateProjectRepositories < ActiveRecord::Migration[5.0]
   def change
     create_table :project_repositories, id: :bigserial do |t|
       t.references :shard, null: false, index: true, foreign_key: { on_delete: :restrict }
-      t.string :disk_path, null: false, index: { unique: true }
+      t.string :disk_path, null: false, index: { unique: true } # rubocop:disable Migration/AddLimitToStringColumns
       t.references :project, null: false, index: { unique: true }, foreign_key: { on_delete: :cascade }
     end
   end
diff --git a/db/migrate/20181123144235_create_suggestions.rb b/db/migrate/20181123144235_create_suggestions.rb
index 1723f6de7eb..78888517db5 100644
--- a/db/migrate/20181123144235_create_suggestions.rb
+++ b/db/migrate/20181123144235_create_suggestions.rb
@@ -8,7 +8,7 @@ class CreateSuggestions < ActiveRecord::Migration[5.0]
       t.references :note, foreign_key: { on_delete: :cascade }, null: false
       t.integer :relative_order, null: false, limit: 2
       t.boolean :applied, null: false, default: false
-      t.string :commit_id
+      t.string :commit_id # rubocop:disable Migration/AddLimitToStringColumns
       t.text :from_content, null: false
       t.text :to_content, null: false
 
diff --git a/db/migrate/20181128123704_add_state_to_pool_repository.rb b/db/migrate/20181128123704_add_state_to_pool_repository.rb
index 714232ede56..04bbcf24f62 100644
--- a/db/migrate/20181128123704_add_state_to_pool_repository.rb
+++ b/db/migrate/20181128123704_add_state_to_pool_repository.rb
@@ -9,7 +9,7 @@ class AddStateToPoolRepository < ActiveRecord::Migration[5.0]
   # the transactions don't have to be disabled
   # rubocop: disable Migration/AddConcurrentForeignKey, Migration/AddIndex
   def change
-    add_column(:pool_repositories, :state, :string, null: true)
+    add_column(:pool_repositories, :state, :string, null: true) # rubocop:disable Migration/AddLimitToStringColumns
 
     add_column :pool_repositories, :source_project_id, :integer
     add_index :pool_repositories, :source_project_id, unique: true
diff --git a/db/migrate/20181129104854_add_token_encrypted_to_ci_builds.rb b/db/migrate/20181129104854_add_token_encrypted_to_ci_builds.rb
index 11b98203793..62a7421eae0 100644
--- a/db/migrate/20181129104854_add_token_encrypted_to_ci_builds.rb
+++ b/db/migrate/20181129104854_add_token_encrypted_to_ci_builds.rb
@@ -6,6 +6,6 @@ class AddTokenEncryptedToCiBuilds < ActiveRecord::Migration[5.0]
   DOWNTIME = false
 
   def change
-    add_column :ci_builds, :token_encrypted, :string
+    add_column :ci_builds, :token_encrypted, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181203002526_add_project_bfg_object_map_column.rb b/db/migrate/20181203002526_add_project_bfg_object_map_column.rb
index 8b42cd6f941..5e6d416895c 100644
--- a/db/migrate/20181203002526_add_project_bfg_object_map_column.rb
+++ b/db/migrate/20181203002526_add_project_bfg_object_map_column.rb
@@ -4,6 +4,6 @@ class AddProjectBfgObjectMapColumn < ActiveRecord::Migration[5.0]
   DOWNTIME = false
 
   def change
-    add_column :projects, :bfg_object_map, :string
+    add_column :projects, :bfg_object_map, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181211092510_add_name_author_id_and_sha_to_releases.rb b/db/migrate/20181211092510_add_name_author_id_and_sha_to_releases.rb
index 60815e0c31a..3ab808ba667 100644
--- a/db/migrate/20181211092510_add_name_author_id_and_sha_to_releases.rb
+++ b/db/migrate/20181211092510_add_name_author_id_and_sha_to_releases.rb
@@ -7,7 +7,7 @@ class AddNameAuthorIdAndShaToReleases < ActiveRecord::Migration[5.0]
 
   def change
     add_column :releases, :author_id, :integer
-    add_column :releases, :name, :string
-    add_column :releases, :sha, :string
+    add_column :releases, :name, :string # rubocop:disable Migration/AddLimitToStringColumns
+    add_column :releases, :sha, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181212171634_create_error_tracking_settings.rb b/db/migrate/20181212171634_create_error_tracking_settings.rb
index 18c38bd2c47..950b9a88005 100644
--- a/db/migrate/20181212171634_create_error_tracking_settings.rb
+++ b/db/migrate/20181212171634_create_error_tracking_settings.rb
@@ -6,6 +6,7 @@ class CreateErrorTrackingSettings < ActiveRecord::Migration[5.0]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :project_error_tracking_settings, id: :int, primary_key: :project_id, default: nil do |t|
       t.boolean :enabled, null: false, default: true
       t.string :api_url, null: false
@@ -13,5 +14,6 @@ class CreateErrorTrackingSettings < ActiveRecord::Migration[5.0]
       t.string :encrypted_token_iv
       t.foreign_key :projects, column: :project_id, on_delete: :cascade
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20181228175414_create_releases_link_table.rb b/db/migrate/20181228175414_create_releases_link_table.rb
index 03558202137..168c4722cc1 100644
--- a/db/migrate/20181228175414_create_releases_link_table.rb
+++ b/db/migrate/20181228175414_create_releases_link_table.rb
@@ -6,6 +6,7 @@ class CreateReleasesLinkTable < ActiveRecord::Migration[5.0]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :release_links, id: :bigserial do |t|
       t.references :release, null: false, index: false, foreign_key: { on_delete: :cascade }
       t.string :url, null: false
@@ -15,5 +16,6 @@ class CreateReleasesLinkTable < ActiveRecord::Migration[5.0]
       t.index [:release_id, :url], unique: true
       t.index [:release_id, :name], unique: true
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20190109153125_add_merge_request_external_diffs.rb b/db/migrate/20190109153125_add_merge_request_external_diffs.rb
index c67903c7f67..a680856a3d8 100644
--- a/db/migrate/20190109153125_add_merge_request_external_diffs.rb
+++ b/db/migrate/20190109153125_add_merge_request_external_diffs.rb
@@ -11,7 +11,7 @@ class AddMergeRequestExternalDiffs < ActiveRecord::Migration[5.0]
 
   def change
     # Allow the merge request diff to store details about an external file
-    add_column :merge_request_diffs, :external_diff, :string
+    add_column :merge_request_diffs, :external_diff, :string # rubocop:disable Migration/AddLimitToStringColumns
     add_column :merge_request_diffs, :external_diff_store, :integer
     add_column :merge_request_diffs, :stored_externally, :boolean
 
diff --git a/db/migrate/20190114172110_add_domain_to_cluster.rb b/db/migrate/20190114172110_add_domain_to_cluster.rb
index 58d7664b8c0..d8f10af9cad 100644
--- a/db/migrate/20190114172110_add_domain_to_cluster.rb
+++ b/db/migrate/20190114172110_add_domain_to_cluster.rb
@@ -4,6 +4,6 @@ class AddDomainToCluster < ActiveRecord::Migration[5.0]
   DOWNTIME = false
 
   def change
-    add_column :clusters, :domain, :string
+    add_column :clusters, :domain, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20190115092821_add_columns_project_error_tracking_settings.rb b/db/migrate/20190115092821_add_columns_project_error_tracking_settings.rb
index 190b6f958fd..afed929cce4 100644
--- a/db/migrate/20190115092821_add_columns_project_error_tracking_settings.rb
+++ b/db/migrate/20190115092821_add_columns_project_error_tracking_settings.rb
@@ -6,8 +6,8 @@ class AddColumnsProjectErrorTrackingSettings < ActiveRecord::Migration[5.0]
   DOWNTIME = false
 
   def change
-    add_column :project_error_tracking_settings, :project_name, :string
-    add_column :project_error_tracking_settings, :organization_name, :string
+    add_column :project_error_tracking_settings, :project_name, :string # rubocop:disable Migration/AddLimitToStringColumns
+    add_column :project_error_tracking_settings, :organization_name, :string # rubocop:disable Migration/AddLimitToStringColumns
 
     change_column_default :project_error_tracking_settings, :enabled, from: true, to: false
 
diff --git a/db/migrate/20190116234221_add_sorting_fields_to_user_preference.rb b/db/migrate/20190116234221_add_sorting_fields_to_user_preference.rb
index 7bf581fe9b0..39aab600546 100644
--- a/db/migrate/20190116234221_add_sorting_fields_to_user_preference.rb
+++ b/db/migrate/20190116234221_add_sorting_fields_to_user_preference.rb
@@ -10,8 +10,8 @@ class AddSortingFieldsToUserPreference < ActiveRecord::Migration[5.0]
   DOWNTIME = false
 
   def up
-    add_column :user_preferences, :issues_sort, :string
-    add_column :user_preferences, :merge_requests_sort, :string
+    add_column :user_preferences, :issues_sort, :string # rubocop:disable Migration/AddLimitToStringColumns
+    add_column :user_preferences, :merge_requests_sort, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 
   def down
diff --git a/db/migrate/20190301182457_add_external_hostname_to_ingress_and_knative.rb b/db/migrate/20190301182457_add_external_hostname_to_ingress_and_knative.rb
index 2c3a54b12a9..37ba1090cf0 100644
--- a/db/migrate/20190301182457_add_external_hostname_to_ingress_and_knative.rb
+++ b/db/migrate/20190301182457_add_external_hostname_to_ingress_and_knative.rb
@@ -4,7 +4,7 @@ class AddExternalHostnameToIngressAndKnative < ActiveRecord::Migration[5.0]
   DOWNTIME = false
 
   def change
-    add_column :clusters_applications_ingress, :external_hostname, :string
-    add_column :clusters_applications_knative, :external_hostname, :string
+    add_column :clusters_applications_ingress, :external_hostname, :string # rubocop:disable Migration/AddLimitToStringColumns
+    add_column :clusters_applications_knative, :external_hostname, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20190320174702_add_lets_encrypt_notification_email_to_application_settings.rb b/db/migrate/20190320174702_add_lets_encrypt_notification_email_to_application_settings.rb
index e9cf2af84a5..aeabf4e3cb4 100644
--- a/db/migrate/20190320174702_add_lets_encrypt_notification_email_to_application_settings.rb
+++ b/db/migrate/20190320174702_add_lets_encrypt_notification_email_to_application_settings.rb
@@ -10,6 +10,6 @@ class AddLetsEncryptNotificationEmailToApplicationSettings < ActiveRecord::Migra
   DOWNTIME = false
 
   def change
-    add_column :application_settings, :lets_encrypt_notification_email, :string
+    add_column :application_settings, :lets_encrypt_notification_email, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20190325105715_add_fields_to_user_preferences.rb b/db/migrate/20190325105715_add_fields_to_user_preferences.rb
index 9ea3b4f9cd8..4da5c496147 100644
--- a/db/migrate/20190325105715_add_fields_to_user_preferences.rb
+++ b/db/migrate/20190325105715_add_fields_to_user_preferences.rb
@@ -11,7 +11,7 @@ class AddFieldsToUserPreferences < ActiveRecord::Migration[5.0]
   DOWNTIME = false
 
   def up
-    add_column(:user_preferences, :timezone, :string)
+    add_column(:user_preferences, :timezone, :string) # rubocop:disable Migration/AddLimitToStringColumns
     add_column(:user_preferences, :time_display_relative, :boolean)
     add_column(:user_preferences, :time_format_in_24h, :boolean)
   end
diff --git a/db/migrate/20190327163904_add_notification_email_to_notification_settings.rb b/db/migrate/20190327163904_add_notification_email_to_notification_settings.rb
index 2f3069032a1..d912f922510 100644
--- a/db/migrate/20190327163904_add_notification_email_to_notification_settings.rb
+++ b/db/migrate/20190327163904_add_notification_email_to_notification_settings.rb
@@ -6,6 +6,6 @@ class AddNotificationEmailToNotificationSettings < ActiveRecord::Migration[5.0]
   DOWNTIME = false
 
   def change
-    add_column :notification_settings, :notification_email, :string
+    add_column :notification_settings, :notification_email, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20190402150158_backport_enterprise_schema.rb b/db/migrate/20190402150158_backport_enterprise_schema.rb
index 8762cc53ed7..3f13b68c2f3 100644
--- a/db/migrate/20190402150158_backport_enterprise_schema.rb
+++ b/db/migrate/20190402150158_backport_enterprise_schema.rb
@@ -2,6 +2,7 @@
 
 # rubocop: disable Metrics/AbcSize
 # rubocop: disable Migration/Datetime
+# rubocop: disable Migration/AddLimitToStringColumns
 class BackportEnterpriseSchema < ActiveRecord::Migration[5.0]
   include Gitlab::Database::MigrationHelpers
 
@@ -2190,3 +2191,4 @@ class BackportEnterpriseSchema < ActiveRecord::Migration[5.0]
 end
 # rubocop: enable Metrics/AbcSize
 # rubocop: enable Migration/Datetime
+# rubocop: enable Migration/AddLimitToStringColumns
diff --git a/db/migrate/20190409224933_add_name_to_geo_nodes.rb b/db/migrate/20190409224933_add_name_to_geo_nodes.rb
index 2dff81b429c..65c01683995 100644
--- a/db/migrate/20190409224933_add_name_to_geo_nodes.rb
+++ b/db/migrate/20190409224933_add_name_to_geo_nodes.rb
@@ -10,7 +10,7 @@ class AddNameToGeoNodes < ActiveRecord::Migration[5.0]
   DOWNTIME = false
 
   def up
-    add_column :geo_nodes, :name, :string
+    add_column :geo_nodes, :name, :string # rubocop:disable Migration/AddLimitToStringColumns
 
     # url is also unique, and its type and size is identical to the name column,
     # so this is safe.
diff --git a/db/migrate/20190422082247_create_project_metrics_settings.rb b/db/migrate/20190422082247_create_project_metrics_settings.rb
index 3e21dd0a934..a0a2ed64820 100644
--- a/db/migrate/20190422082247_create_project_metrics_settings.rb
+++ b/db/migrate/20190422082247_create_project_metrics_settings.rb
@@ -7,7 +7,7 @@ class CreateProjectMetricsSettings < ActiveRecord::Migration[5.0]
 
   def change
     create_table :project_metrics_settings, id: :int, primary_key: :project_id, default: nil do |t|
-      t.string :external_dashboard_url, null: false
+      t.string :external_dashboard_url, null: false # rubocop:disable Migration/AddLimitToStringColumns
       t.foreign_key :projects, column: :project_id, on_delete: :cascade
     end
   end
diff --git a/db/migrate/20190429082448_create_pages_domain_acme_orders.rb b/db/migrate/20190429082448_create_pages_domain_acme_orders.rb
index af811e83518..ca1796d054c 100644
--- a/db/migrate/20190429082448_create_pages_domain_acme_orders.rb
+++ b/db/migrate/20190429082448_create_pages_domain_acme_orders.rb
@@ -10,6 +10,7 @@ class CreatePagesDomainAcmeOrders < ActiveRecord::Migration[5.1]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :pages_domain_acme_orders do |t|
       t.references :pages_domain, null: false, index: true, foreign_key: { on_delete: :cascade }, type: :integer
 
@@ -24,5 +25,6 @@ class CreatePagesDomainAcmeOrders < ActiveRecord::Migration[5.1]
       t.text :encrypted_private_key, null: false
       t.text :encrypted_private_key_iv, null: false
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20190430131225_create_issue_tracker_data.rb b/db/migrate/20190430131225_create_issue_tracker_data.rb
index 7859bea9c22..d2134ad82c7 100644
--- a/db/migrate/20190430131225_create_issue_tracker_data.rb
+++ b/db/migrate/20190430131225_create_issue_tracker_data.rb
@@ -9,6 +9,7 @@ class CreateIssueTrackerData < ActiveRecord::Migration[5.1]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :issue_tracker_data do |t|
       t.references :service, foreign_key: { on_delete: :cascade }, type: :integer, index: true, null: false
       t.timestamps_with_timezone
@@ -19,5 +20,6 @@ class CreateIssueTrackerData < ActiveRecord::Migration[5.1]
       t.string :encrypted_new_issue_url
       t.string :encrypted_new_issue_url_iv
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20190430142025_create_jira_tracker_data.rb b/db/migrate/20190430142025_create_jira_tracker_data.rb
index d328ad63854..5e53e5a701a 100644
--- a/db/migrate/20190430142025_create_jira_tracker_data.rb
+++ b/db/migrate/20190430142025_create_jira_tracker_data.rb
@@ -9,6 +9,7 @@ class CreateJiraTrackerData < ActiveRecord::Migration[5.1]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :jira_tracker_data do |t|
       t.references :service, foreign_key: { on_delete: :cascade }, type: :integer, index: true, null: false
       t.timestamps_with_timezone
@@ -22,5 +23,6 @@ class CreateJiraTrackerData < ActiveRecord::Migration[5.1]
       t.string :encrypted_password_iv
       t.string :jira_issue_transition_id
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20190514105711_create_ip_restriction.rb b/db/migrate/20190514105711_create_ip_restriction.rb
index dfafbe32ad1..69f8c1b8c4e 100644
--- a/db/migrate/20190514105711_create_ip_restriction.rb
+++ b/db/migrate/20190514105711_create_ip_restriction.rb
@@ -12,7 +12,7 @@ class CreateIpRestriction < ActiveRecord::Migration[5.1]
                    type: :integer,
                    null: false,
                    index: true
-      t.string :range, null: false
+      t.string :range, null: false # rubocop:disable Migration/AddLimitToStringColumns
     end
 
     add_foreign_key(:ip_restrictions, :namespaces, column: :group_id, on_delete: :cascade) # rubocop: disable Migration/AddConcurrentForeignKey
diff --git a/db/migrate/20190527011309_add_required_template_name_to_application_settings.rb b/db/migrate/20190527011309_add_required_template_name_to_application_settings.rb
index 6cbac0ed507..5c47e6f33c2 100644
--- a/db/migrate/20190527011309_add_required_template_name_to_application_settings.rb
+++ b/db/migrate/20190527011309_add_required_template_name_to_application_settings.rb
@@ -10,6 +10,6 @@ class AddRequiredTemplateNameToApplicationSettings < ActiveRecord::Migration[5.1
   DOWNTIME = false
 
   def change
-    add_column :application_settings, :required_instance_ci_template, :string, null: true
+    add_column :application_settings, :required_instance_ci_template, :string, null: true # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20190606054742_add_token_encrypted_to_operations_feature_flags_clients.rb b/db/migrate/20190606054742_add_token_encrypted_to_operations_feature_flags_clients.rb
index 024b5bd2ba5..2db4dc85750 100644
--- a/db/migrate/20190606054742_add_token_encrypted_to_operations_feature_flags_clients.rb
+++ b/db/migrate/20190606054742_add_token_encrypted_to_operations_feature_flags_clients.rb
@@ -6,6 +6,6 @@ class AddTokenEncryptedToOperationsFeatureFlagsClients < ActiveRecord::Migration
   DOWNTIME = false
 
   def change
-    add_column :operations_feature_flags_clients, :token_encrypted, :string
+    add_column :operations_feature_flags_clients, :token_encrypted, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20190613044655_add_username_to_deploy_tokens.rb b/db/migrate/20190613044655_add_username_to_deploy_tokens.rb
index 793553afe35..a0acb02013b 100644
--- a/db/migrate/20190613044655_add_username_to_deploy_tokens.rb
+++ b/db/migrate/20190613044655_add_username_to_deploy_tokens.rb
@@ -4,6 +4,6 @@ class AddUsernameToDeployTokens < ActiveRecord::Migration[5.1]
   DOWNTIME = false
 
   def change
-    add_column :deploy_tokens, :username, :string
+    add_column :deploy_tokens, :username, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20190613073003_create_project_aliases.rb b/db/migrate/20190613073003_create_project_aliases.rb
index 5a2c2ba0cf2..896d3ca5813 100644
--- a/db/migrate/20190613073003_create_project_aliases.rb
+++ b/db/migrate/20190613073003_create_project_aliases.rb
@@ -8,7 +8,7 @@ class CreateProjectAliases < ActiveRecord::Migration[5.1]
   def change
     create_table :project_aliases do |t|
       t.references :project, null: false, index: true, foreign_key: { on_delete: :cascade }, type: :integer
-      t.string :name, null: false, index: { unique: true }
+      t.string :name, null: false, index: { unique: true } # rubocop:disable Migration/AddLimitToStringColumns
 
       t.timestamps_with_timezone null: false
     end
diff --git a/db/migrate/20190621151636_add_merge_request_rebase_jid.rb b/db/migrate/20190621151636_add_merge_request_rebase_jid.rb
index 1fed5690ead..6c1081732e8 100644
--- a/db/migrate/20190621151636_add_merge_request_rebase_jid.rb
+++ b/db/migrate/20190621151636_add_merge_request_rebase_jid.rb
@@ -4,6 +4,6 @@ class AddMergeRequestRebaseJid < ActiveRecord::Migration[5.1]
   DOWNTIME = false
 
   def change
-    add_column :merge_requests, :rebase_jid, :string
+    add_column :merge_requests, :rebase_jid, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/migrate/20190624123615_add_grafana_url_to_settings.rb b/db/migrate/20190624123615_add_grafana_url_to_settings.rb
index 61efe64a7a1..835ec4e9094 100644
--- a/db/migrate/20190624123615_add_grafana_url_to_settings.rb
+++ b/db/migrate/20190624123615_add_grafana_url_to_settings.rb
@@ -8,8 +8,10 @@ class AddGrafanaUrlToSettings < ActiveRecord::Migration[5.1]
   DOWNTIME = false
 
   def up
+    # rubocop:disable Migration/AddLimitToStringColumns
     add_column_with_default(:application_settings, :grafana_url, :string,
                             default: '/-/grafana', allow_null: false)
+    # rubocop:enable Migration/AddLimitToStringColumns
   end
 
   def down
diff --git a/db/migrate/20190711124721_create_job_variables.rb b/db/migrate/20190711124721_create_job_variables.rb
index a860522f39e..4ff4b031d8f 100644
--- a/db/migrate/20190711124721_create_job_variables.rb
+++ b/db/migrate/20190711124721_create_job_variables.rb
@@ -10,6 +10,7 @@ class CreateJobVariables < ActiveRecord::Migration[5.1]
   DOWNTIME = false
 
   def change
+    # rubocop:disable Migration/AddLimitToStringColumns
     create_table :ci_job_variables do |t|
       t.string :key, null: false
       t.text :encrypted_value
@@ -17,6 +18,7 @@ class CreateJobVariables < ActiveRecord::Migration[5.1]
       t.references :job, null: false, index: true, foreign_key: { to_table: :ci_builds, on_delete: :cascade }
       t.integer :variable_type, null: false, limit: 2, default: 1
     end
+    # rubocop:enable Migration/AddLimitToStringColumns
 
     add_index :ci_job_variables, [:key, :job_id], unique: true
   end
diff --git a/db/post_migrate/20181013005024_remove_koding_from_application_settings.rb b/db/post_migrate/20181013005024_remove_koding_from_application_settings.rb
index 550ad94f4ab..b6e5473e896 100644
--- a/db/post_migrate/20181013005024_remove_koding_from_application_settings.rb
+++ b/db/post_migrate/20181013005024_remove_koding_from_application_settings.rb
@@ -12,6 +12,6 @@ class RemoveKodingFromApplicationSettings < ActiveRecord::Migration[4.2]
 
   def down
     add_column :application_settings, :koding_enabled, :boolean # rubocop:disable Migration/SaferBooleanColumn
-    add_column :application_settings, :koding_url, :string
+    add_column :application_settings, :koding_url, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/post_migrate/20190404231137_remove_alternate_url_from_geo_nodes.rb b/db/post_migrate/20190404231137_remove_alternate_url_from_geo_nodes.rb
index 785ceb2fb28..8e7ef0ec54f 100644
--- a/db/post_migrate/20190404231137_remove_alternate_url_from_geo_nodes.rb
+++ b/db/post_migrate/20190404231137_remove_alternate_url_from_geo_nodes.rb
@@ -16,6 +16,6 @@ class RemoveAlternateUrlFromGeoNodes < ActiveRecord::Migration[5.0]
   end
 
   def down
-    add_column :geo_nodes, :alternate_url, :string
+    add_column :geo_nodes, :alternate_url, :string # rubocop:disable Migration/AddLimitToStringColumns
   end
 end
diff --git a/db/post_migrate/20190625184066_remove_sentry_from_application_settings.rb b/db/post_migrate/20190625184066_remove_sentry_from_application_settings.rb
index 427df343193..9d71bfafffb 100644
--- a/db/post_migrate/20190625184066_remove_sentry_from_application_settings.rb
+++ b/db/post_migrate/20190625184066_remove_sentry_from_application_settings.rb
@@ -32,7 +32,7 @@ class RemoveSentryFromApplicationSettings < ActiveRecord::Migration[5.0]
     end
 
     SENTRY_DSN_COLUMNS.each do |column|
-      add_column(:application_settings, column, :string) unless column_exists?(:application_settings, column)
+      add_column(:application_settings, column, :string) unless column_exists?(:application_settings, column) # rubocop:disable Migration/AddLimitToStringColumns
     end
   end
 end
diff --git a/rubocop/cop/migration/add_limit_to_string_columns.rb b/rubocop/cop/migration/add_limit_to_string_columns.rb
new file mode 100644
index 00000000000..30affcbb089
--- /dev/null
+++ b/rubocop/cop/migration/add_limit_to_string_columns.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+require_relative '../../migration_helpers'
+
+module RuboCop
+  module Cop
+    module Migration
+      # Cop that enforces length constraints to string columns
+      class AddLimitToStringColumns < RuboCop::Cop::Cop
+        include MigrationHelpers
+
+        ADD_COLUMNS_METHODS = %i(add_column add_column_with_default).freeze
+
+        MSG = 'String columns should have a limit constraint. 255 is suggested'.freeze
+
+        def on_def(node)
+          return unless in_migration?(node)
+
+          node.each_descendant(:send) do |send_node|
+            next unless string_operation?(send_node)
+
+            add_offense(send_node, location: :selector) unless limit_on_string_column?(send_node)
+          end
+        end
+
+        private
+
+        def string_operation?(node)
+          modifier = node.children[0]
+          migration_method = node.children[1]
+
+          if migration_method == :string
+            modifier.type == :lvar
+          elsif ADD_COLUMNS_METHODS.include?(migration_method)
+            modifier.nil? && string_column?(node.children[4])
+          end
+        end
+
+        def string_column?(column_type)
+          column_type.type == :sym && column_type.value == :string
+        end
+
+        def limit_on_string_column?(node)
+          migration_method = node.children[1]
+
+          if migration_method == :string
+            limit_present?(node.children)
+          elsif ADD_COLUMNS_METHODS.include?(migration_method)
+            limit_present?(node)
+          end
+        end
+
+        def limit_present?(statement)
+          !(statement.to_s =~ /:limit/).nil?
+        end
+      end
+    end
+  end
+end
diff --git a/rubocop/rubocop.rb b/rubocop/rubocop.rb
index 58a7ead6f13..d1328c4eb38 100644
--- a/rubocop/rubocop.rb
+++ b/rubocop/rubocop.rb
@@ -17,6 +17,7 @@ require_relative 'cop/migration/add_column'
 require_relative 'cop/migration/add_concurrent_foreign_key'
 require_relative 'cop/migration/add_concurrent_index'
 require_relative 'cop/migration/add_index'
+require_relative 'cop/migration/add_limit_to_string_columns'
 require_relative 'cop/migration/add_reference'
 require_relative 'cop/migration/add_timestamps'
 require_relative 'cop/migration/datetime'
diff --git a/spec/rubocop/cop/migration/add_limit_to_string_columns_spec.rb b/spec/rubocop/cop/migration/add_limit_to_string_columns_spec.rb
new file mode 100644
index 00000000000..97a3ae8f2bc
--- /dev/null
+++ b/spec/rubocop/cop/migration/add_limit_to_string_columns_spec.rb
@@ -0,0 +1,268 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+require 'rubocop'
+require 'rubocop/rspec/support'
+
+require_relative '../../../../rubocop/cop/migration/add_limit_to_string_columns'
+
+describe RuboCop::Cop::Migration::AddLimitToStringColumns do
+  include CopHelper
+
+  subject(:cop) { described_class.new }
+
+  context 'in migration' do
+    before do
+      allow(cop).to receive(:in_migration?).and_return(true)
+
+      inspect_source(migration)
+    end
+
+    context 'when creating a table' do
+      context 'with string columns and limit' do
+        let(:migration) do
+          %q(
+           class CreateUsers < ActiveRecord::Migration[5.2]
+             DOWNTIME = false
+
+             def change
+               create_table :users do |t|
+                 t.string :username, null: false, limit: 255
+                 t.timestamps_with_timezone null: true
+               end
+             end
+           end
+          )
+        end
+
+        it 'register no offense' do
+          expect(cop.offenses.size).to eq(0)
+        end
+
+        context 'with limit in a different position' do
+          let(:migration) do
+            %q(
+             class CreateUsers < ActiveRecord::Migration[5.2]
+               DOWNTIME = false
+
+               def change
+                 create_table :users do |t|
+                   t.string :username, limit: 255, null: false
+                   t.timestamps_with_timezone null: true
+                 end
+               end
+             end
+            )
+          end
+
+          it 'registers an offense' do
+            expect(cop.offenses.size).to eq(0)
+          end
+        end
+      end
+
+      context 'with string columns and no limit' do
+        let(:migration) do
+          %q(
+           class CreateUsers < ActiveRecord::Migration[5.2]
+             DOWNTIME = false
+
+             def change
+               create_table :users do |t|
+                 t.string :username, null: false
+                 t.timestamps_with_timezone null: true
+               end
+             end
+           end
+          )
+        end
+
+        it 'registers an offense' do
+          expect(cop.offenses.size).to eq(1)
+          expect(cop.offenses.first.message)
+            .to eq('String columns should have a limit constraint. 255 is suggested')
+        end
+      end
+
+      context 'with no string columns' do
+        let(:migration) do
+          %q(
+            class CreateMilestoneReleases < ActiveRecord::Migration[5.2]
+              DOWNTIME = false
+
+              def change
+                create_table :milestone_releases do |t|
+                  t.integer :milestone_id
+                  t.integer :release_id
+                end
+              end
+            end
+          )
+        end
+
+        it 'register no offense' do
+          expect(cop.offenses.size).to eq(0)
+        end
+      end
+    end
+
+    context 'when adding columns' do
+      context 'with string columns with limit' do
+        let(:migration) do
+          %q(
+            class AddEmailToUsers < ActiveRecord::Migration[5.2]
+              DOWNTIME = false
+
+              def change
+                add_column :users, :email, :string, limit: 255
+              end
+            end
+          )
+        end
+
+        it 'registers no offense' do
+          expect(cop.offenses.size).to eq(0)
+        end
+
+        context 'with limit in a different position' do
+          let(:migration) do
+            %q(
+              class AddEmailToUsers < ActiveRecord::Migration[5.2]
+                DOWNTIME = false
+
+                def change
+                  add_column :users, :email, :string, limit: 255, default: 'example@email.com'
+                end
+              end
+            )
+          end
+
+          it 'registers no offense' do
+            expect(cop.offenses.size).to eq(0)
+          end
+        end
+      end
+
+      context 'with string columns with no limit' do
+        let(:migration) do
+          %q(
+            class AddEmailToUsers < ActiveRecord::Migration[5.2]
+              DOWNTIME = false
+
+              def change
+                add_column :users, :email, :string
+              end
+            end
+          )
+        end
+
+        it 'registers offense' do
+          expect(cop.offenses.size).to eq(1)
+          expect(cop.offenses.first.message)
+            .to eq('String columns should have a limit constraint. 255 is suggested')
+        end
+      end
+
+      context 'with no string columns' do
+        let(:migration) do
+          %q(
+            class AddEmailToUsers < ActiveRecord::Migration[5.2]
+              DOWNTIME = false
+
+              def change
+                add_column :users, :active, :boolean, default: false
+              end
+            end
+          )
+        end
+
+        it 'registers no offense' do
+          expect(cop.offenses.size).to eq(0)
+        end
+      end
+    end
+
+    context 'with add_column_with_default' do
+      context 'with a limit' do
+        let(:migration) do
+          %q(
+           class AddRuleTypeToApprovalMergeRequestRules < ActiveRecord::Migration[5.2]
+             DOWNTIME = false
+
+             def change
+               add_column_with_default(:approval_merge_request_rules, :rule_type, :string, limit: 2, default: 1)
+             end
+           end
+           )
+        end
+
+        it 'registers no offense' do
+          expect(cop.offenses.size).to eq(0)
+        end
+      end
+
+      context 'without a limit' do
+        let(:migration) do
+          %q(
+           class AddRuleTypeToApprovalMergeRequestRules < ActiveRecord::Migration[5.2]
+             DOWNTIME = false
+
+             def change
+               add_column_with_default(:approval_merge_request_rules, :rule_type, :string, default: 1)
+             end
+           end
+           )
+        end
+
+        it 'registers an offense' do
+          expect(cop.offenses.size).to eq(1)
+        end
+      end
+    end
+
+    context 'with methods' do
+      let(:migration) do
+        %q(
+          class AddEmailToUsers < ActiveRecord::Migration[5.2]
+            DOWNTIME = false
+
+            def change
+              add_column_if_table_not_exists :users, :first_name, :string, limit: 255
+              search_namespace(user_name)
+            end
+
+            def add_column_if_not_exists(table, name, *args)
+              add_column(table, name, *args) unless column_exists?(table, name)
+            end
+
+            def search_namespace(username)
+               Uniquify.new.string(username) do |str|
+                query = "SELECT id FROM namespaces WHERE parent_id IS NULL AND path='#{str}' LIMIT 1"
+                connection.exec_query(query)
+              end
+            end
+          end
+        )
+      end
+
+      it 'registers no offense' do
+        expect(cop.offenses.size).to eq(0)
+      end
+    end
+  end
+
+  context 'outside of migrations' do
+    let(:active_record_model) do
+      %q(
+      class User < ApplicationRecord
+      end
+      )
+    end
+
+    it 'registers no offense' do
+      inspect_source(active_record_model)
+
+      expect(cop.offenses.size).to eq(0)
+    end
+  end
+end