Merge pull request #693 from koic/fix_an_error_for_rails_unused_ignor…

…ed_columns

[Fix #692] Fix an error for `Rails/UnusedIgnoredColumns`

changelog/fix_an_error_for_rails_unused_ignored_columns.md

@@ -0,0 +1 @@
+* [#692](https://github.com/rubocop/rubocop-rails/issues/692): Fix an error for `Rails/UnusedIgnoredColumns` when using no tables db/schema.rb. ([@koic][])

lib/rubocop/rails/schema_loader/schema.rb

@@ -32,6 +32,8 @@ def build!(ast)
           raise "Unexpected type: #{ast.type}" unless ast.block_type?
 
           each_table(ast) do |table_def|
+            next unless table_def.method?(:create_table)
+
             @tables << Table.new(table_def)
           end
 
@@ -56,6 +58,7 @@ def each_table(ast)
 
         def each_add_index(ast)
           ast.body.children.each do |node|
+            next unless node.respond_to?(:send_type?)
             next if !node&.send_type? || !node.method?(:add_index)
 
             yield(node)

spec/rubocop/cop/rails/unused_ignored_columns_spec.rb

@@ -106,4 +106,25 @@ class User < ApplicationRecord
       end
     end
   end
+
+  context 'with no tables db/schema.rb' do
+    include_context 'with SchemaLoader'
+
+    let(:schema) { <<~RUBY }
+      ActiveRecord::Schema.define(version: 2020_02_02_075409) do
+        enable_extension 'plpgsql'
+      end
+    RUBY
+
+    context 'with an unused ignored column as a Symbol' do
+      # NOTE: For example, it is not possible to track externally managed databases.
+      it 'does not register an offense' do
+        expect_no_offenses(<<~RUBY)
+          class User < ApplicationRecord
+            self.ignored_columns = [:real_name]
+          end
+        RUBY
+      end
+    end
+  end
 end