From c53681ed1b393d70569f6a80235afdf71e5e6faf Mon Sep 17 00:00:00 2001
From: rbr <rbr@users.noreply.github.com>
Date: Sun, 12 Jun 2016 15:57:20 +0200
Subject: [PATCH] Add options for uniqueness validations. Resolves #319

---
 README.md             | 24 ++++++++++++++++++++++++
 lib/paranoia.rb       |  9 +++++++--
 test/paranoia_test.rb | 36 ++++++++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 5faafe82..a153c0e0 100644
--- a/README.md
+++ b/README.md
@@ -181,6 +181,30 @@ Client.restore(id, :recursive => true)
 client.restore(:recursive => true)
 ```
 
+If you want to validate uniqueness but want to include deleted records:
+
+``` ruby
+class Client < ActiveRecord::Base
+  acts_as_paranoid
+
+  validates :name, uniqueness: { paranoia: :with_deleted }
+
+  ...
+end
+```
+
+If you don't use the default_scope and want to validate uniqueness but want to exclude deleted records:
+
+``` ruby
+class Client < ActiveRecord::Base
+  acts_as_paranoid without_default_scope: true
+
+  validates :name, uniqueness: { paranoia: :without_deleted }
+
+  ...
+end
+```
+
 For more information, please look at the tests.
 
 #### About indexes:
diff --git a/lib/paranoia.rb b/lib/paranoia.rb
index ec2c72b8..b03a4b87 100644
--- a/lib/paranoia.rb
+++ b/lib/paranoia.rb
@@ -212,8 +212,9 @@ def self.acts_as_paranoid(options={})
     alias_method :destroy_without_paranoia, :destroy
 
     include Paranoia
-    class_attribute :paranoia_column, :paranoia_sentinel_value
+    class_attribute :paranoia_column, :paranoia_sentinel_value, :paranoid_by_default
 
+    self.paranoid_by_default = !options[:without_default_scope]
     self.paranoia_column = (options[:column] || :deleted_at).to_s
     self.paranoia_sentinel_value = options.fetch(:sentinel_value) { Paranoia.default_sentinel_value }
     def self.paranoia_scope
@@ -221,7 +222,7 @@ def self.paranoia_scope
     end
     class << self; alias_method :without_deleted, :paranoia_scope end
 
-    unless options[:without_default_scope]
+    if paranoid_by_default
       default_scope { paranoia_scope }
     end
 
@@ -266,6 +267,10 @@ module UniquenessParanoiaValidator
       def build_relation(klass, table, attribute, value)
         relation = super(klass, table, attribute, value)
         return relation unless klass.respond_to?(:paranoia_column)
+
+        add_paranoia_scope = (klass.paranoid_by_default && options[:paranoia] != :with_deleted) || (!klass.paranoid_by_default && options[:paranoia] == :without_deleted)
+        return relation unless add_paranoia_scope
+
         arel_paranoia_scope = klass.arel_table[klass.paranoia_column].eq(klass.paranoia_sentinel_value)
         if ActiveRecord::VERSION::STRING >= "5.0"
           relation.where(arel_paranoia_scope)
diff --git a/test/paranoia_test.rb b/test/paranoia_test.rb
index a1bceeee..5f73cddc 100644
--- a/test/paranoia_test.rb
+++ b/test/paranoia_test.rb
@@ -253,6 +253,24 @@ def test_active_column_model_with_uniqueness_validation_still_works_on_non_delet
     refute b.valid?
   end
 
+  def test_uniqueness_with_deleted
+    a = ParanoidWithUniquenessWithDeleted.create!(name: "A")
+    b = ParanoidWithUniquenessWithDeleted.new(name: "A")
+    refute b.valid?
+  end
+
+  def test_uniqueness_without_default_scope_with_deleted
+    a = ParanoidWithoutDefaultScopeWithUniqueness.create!(name: "A")
+    b = ParanoidWithoutDefaultScopeWithUniqueness.new(name: "A")
+    refute b.valid?
+  end
+
+  def test_uniqueness_without_default_scope_without_deleted
+    a = ParanoidWithoutDefaultScopeWithUniquenessWithoutDeleted.create!(name: "A")
+    b = ParanoidWithoutDefaultScopeWithUniquenessWithoutDeleted.new(name: "A")
+    refute b.valid?
+  end
+
   def test_sentinel_value_for_custom_sentinel_models
     model = CustomSentinelModel.new
     assert_equal 0, model.class.count
@@ -1105,6 +1123,24 @@ def paranoia_destroy_attributes
   end
 end
 
+class ParanoidWithUniquenessWithDeleted < ActiveRecord::Base
+  self.table_name = 'featureful_models'
+  acts_as_paranoid
+  validates :name, uniqueness: { paranoia: :with_deleted }
+end
+
+class ParanoidWithoutDefaultScopeWithUniqueness < ActiveRecord::Base
+  self.table_name = 'featureful_models'
+  acts_as_paranoid without_default_scope: true
+  validates :name, uniqueness: true
+end
+
+class ParanoidWithoutDefaultScopeWithUniquenessWithoutDeleted < ActiveRecord::Base
+  self.table_name = 'featureful_models'
+  acts_as_paranoid
+  validates :name, uniqueness: { paranoia: :without_deleted }
+end
+
 class NonParanoidModel < ActiveRecord::Base
 end