Add cop that checks if add_column_with_default is used with up/down methods

3 files changed, 38 insertions, 4 deletions

diff --git a/rubocop/cop/migration/column_with_default.rb b/rubocop/cop/migration/add_column.rb
index 97ee8b11044..d5c8eeeea1f 100644
--- a/rubocop/cop/migration/column_with_default.rb
+++ b/rubocop/cop/migration/add_column.rb
@@ -3,13 +3,13 @@ module RuboCop
     module Migration
       # Cop that checks if columns are added in a way that doesn't require
       # downtime.
-      class ColumnWithDefault < RuboCop::Cop::Cop
+      class AddColumn < RuboCop::Cop::Cop
         include MigrationHelpers
 
         WHITELISTED_TABLES = [:application_settings]
 
-        MSG = 'add_column with a default value requires downtime, ' \
-          'use add_column_with_default instead'
+        MSG = '`add_column` with a default value requires downtime, ' \
+          'use `add_column_with_default` instead'
 
         def on_send(node)
           return unless in_migration?(node)
diff --git a/rubocop/cop/migration/add_column_with_default.rb b/rubocop/cop/migration/add_column_with_default.rb
new file mode 100644
index 00000000000..747d7caf1ef
--- /dev/null
+++ b/rubocop/cop/migration/add_column_with_default.rb
@@ -0,0 +1,34 @@
+require_relative '../../migration_helpers'
+
+module RuboCop
+  module Cop
+    module Migration
+      # Cop that checks if `add_column_with_default` is used with `up`/`down` methods
+      # and not `change`.
+      class AddColumnWithDefault < RuboCop::Cop::Cop
+        include MigrationHelpers
+
+        MSG = '`add_column_with_default` is not reversible so you must manually define ' \
+          'the `up` and `down` methods in your migration class, using `remove_column` in `down`'
+
+        def on_send(node)
+          return unless in_migration?(node)
+
+          name = node.children[1]
+
+          return unless name == :add_column_with_default
+
+          node.each_ancestor(:def) do |def_node|
+            next unless method_name(def_node) == :change
+
+            add_offense(def_node, :name)
+          end
+        end
+
+        def method_name(node)
+          node.children.first
+        end
+      end
+    end
+  end
+end
diff --git a/rubocop/cop/migration/add_index.rb b/rubocop/cop/migration/add_index.rb
index d9247a1f7ea..506af97866f 100644
--- a/rubocop/cop/migration/add_index.rb
+++ b/rubocop/cop/migration/add_index.rb
@@ -5,7 +5,7 @@ module RuboCop
       class AddIndex < RuboCop::Cop::Cop
         include MigrationHelpers
 
-        MSG = 'add_index requires downtime, use add_concurrent_index instead'
+        MSG = '`add_index` requires downtime, use `add_concurrent_index` instead'
 
         def on_def(node)
           return unless in_migration?(node)