Merge pull request #217 from koic/fix_a_false_positive_for_unique_val…

…idation_without_index

[Fix #215] Fix a false positive for `Rails/UniqueValidationWithoutIndex`

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Bug fixes
 
 * [#213](https://github.com/rubocop-hq/rubocop-rails/pull/213): Fix a false positive for `Rails/UniqueValidationWithoutIndex` when using conditions. ([@sunny][])
+* [#215](https://github.com/rubocop-hq/rubocop-rails/issues/215): Fix a false positive for `Rails/UniqueValidationWithoutIndex` when using Expression Indexes. ([@koic][])
 
 ## 2.5.0 (2020-03-24)
 

lib/rubocop/cop/rails/unique_validation_without_index.rb

@@ -32,6 +32,7 @@ class UniqueValidationWithoutIndex < Cop
  def on_send(node)
  return unless node.method?(:validates)
  return unless uniqueness_part(node)
+ return if condition_part?(node)
  return unless schema
  return if with_index?(node)
 
@@ -47,13 +48,21 @@ def with_index?(node)
  table = schema.table_by(name: table_name(klass))
  return true unless table # Skip analysis if it can't find the table
 
- return true if condition_part?(node)
-
  names = column_names(node)
  return true unless names
 
  table.indices.any? do |index|
- index.unique && index.columns.to_set == names
+ index.unique &&
+ (index.columns.to_set == names ||
+ include_column_names_in_expression_index?(index, names))
+ end
+ end
+
+ def include_column_names_in_expression_index?(index, column_names)
+ return false unless (expression_index = index.expression)
+
+ column_names.all? do |column_name|
+ expression_index.include?(column_name)
  end
  end
 

spec/rubocop/cop/rails/unique_validation_without_index_spec.rb

@@ -406,5 +406,46 @@ class User
  RUBY
  end
  end
+
+ context 'with expression indexes' do
+ context 'when column name is included in expression index' do
+ let(:schema) { <<~RUBY }
+ ActiveRecord::Schema.define(version: 2020_02_02_075409) do
+ create_table 'emails', force: :cascade do |t|
+ t.string 'address', null: false
+ t.index 'lower(address)', name: 'index_emails_on_lower_address', unique: true
+ end
+ end
+ RUBY
+
+ it 'does not register an offense' do
+ expect_no_offenses(<<~RUBY)
+ class Email < ApplicationRecord
+ validates :address, presence: true, uniqueness: { case_sensitive: false }, email: true
+ end
+ RUBY
+ end
+ end
+
+ context 'when column name is not included in expression index' do
+ let(:schema) { <<~RUBY }
+ ActiveRecord::Schema.define(version: 2020_02_02_075409) do
+ create_table 'emails', force: :cascade do |t|
+ t.string 'address', null: false
+ t.index 'lower(unexpected_column_name)', name: 'index_emails_on_lower_address', unique: true
+ end
+ end
+ RUBY
+
+ it 'registers an offense' do
+ expect_offense(<<~RUBY)
+ class Email < ApplicationRecord
+ validates :address, presence: true, uniqueness: { case_sensitive: false }, email: true
+ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Uniqueness validation should be with a unique index.
+ end
+ RUBY
+ end
+ end
+ end
  end
 end