Add latest changes from gitlab-org/gitlab@master

2 files changed, 57 insertions, 1 deletions

diff --git a/rubocop/cop/migration/add_columns_to_wide_tables.rb b/rubocop/cop/migration/add_columns_to_wide_tables.rb
new file mode 100644
index 00000000000..4618e4ae890
--- /dev/null
+++ b/rubocop/cop/migration/add_columns_to_wide_tables.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+require_relative '../../migration_helpers'
+
+module RuboCop
+  module Cop
+    module Migration
+      # Cop that prevents adding columns to wide tables.
+      class AddColumnsToWideTables < RuboCop::Cop::Cop
+        include MigrationHelpers
+
+        MSG = '`%s` is a wide table with several columns, addig more should be avoided unless absolutely necessary.' \
+              ' Consider storing the column in a different table or creating a new one.'.freeze
+
+        BLACKLISTED_METHODS = %i[
+          add_column
+          add_column_with_default
+          add_reference
+          add_timestamps_with_timezone
+        ].freeze
+
+        def on_send(node)
+          return unless in_migration?(node)
+
+          method_name = node.children[1]
+          table_name = node.children[2]
+
+          return unless offense?(method_name, table_name)
+
+          add_offense(node, location: :selector, message: format(MSG, table_name.value))
+        end
+
+        private
+
+        def offense?(method_name, table_name)
+          wide_table?(table_name) &&
+            BLACKLISTED_METHODS.include?(method_name)
+        end
+
+        def wide_table?(table_name)
+          table_name && table_name.type == :sym &&
+            WIDE_TABLES.include?(table_name.value)
+        end
+      end
+    end
+  end
+end
diff --git a/rubocop/migration_helpers.rb b/rubocop/migration_helpers.rb
index b5edb502d4c..5fa6f8c2a2c 100644
--- a/rubocop/migration_helpers.rb
+++ b/rubocop/migration_helpers.rb
@@ -6,7 +6,7 @@ module RuboCop
       plan_limits
     ].freeze
 
-    # Blacklisted table due to:
+    # Blacklisted tables due to:
     #   - size in GB (>= 10 GB on GitLab.com as of 02/2020)
     #   - number of records
     BLACKLISTED_TABLES = %i[
@@ -44,6 +44,15 @@ module RuboCop
        web_hook_logs
     ].freeze
 
+    # Blacklisted tables due to:
+    #   - number of columns (> 50 on GitLab.com as of 03/2020)
+    #   - number of records
+    WIDE_TABLES = %i[
+      users
+      projects
+      ci_builds
+    ].freeze
+
     # Returns true if the given node originated from the db/migrate directory.
     def in_migration?(node)
       dirname(node).end_with?('db/migrate', 'db/geo/migrate') || in_post_deployment_migration?(node)