Extract `PredicateBuilder::CaseSensitiveHandler`

Currently uniqueness validator is coupled with building Arel ASTs.
This commit extracts `PredicateBuilder::CaseSensitiveHandler` for
decouple the building Arel ASTs.

1 files changed, 1 insertions, 31 deletions

diff --git a/activerecord/lib/active_record/validations/uniqueness.rb b/activerecord/lib/active_record/validations/uniqueness.rb
index 8c4930a81d..08c4b01439 100644
--- a/activerecord/lib/active_record/validations/uniqueness.rb
+++ b/activerecord/lib/active_record/validations/uniqueness.rb
@@ -50,37 +50,7 @@ module ActiveRecord
       end
 
       def build_relation(klass, attribute, value) # :nodoc:
-        if reflection = klass._reflect_on_association(attribute)
-          attribute = reflection.foreign_key
-          value = value.attributes[reflection.klass.primary_key] unless value.nil?
-        end
-
-        if value.nil?
-          return klass.unscoped.where!(attribute => value)
-        end
-
-        # the attribute may be an aliased attribute
-        if klass.attribute_alias?(attribute)
-          attribute = klass.attribute_alias(attribute)
-        end
-
-        attribute_name = attribute.to_s
-
-        table = klass.arel_table
-        column = klass.columns_hash[attribute_name]
-        cast_type = klass.type_for_attribute(attribute_name)
-
-        comparison = if !options[:case_sensitive]
-          # will use SQL LOWER function before comparison, unless it detects a case insensitive collation
-          klass.connection.case_insensitive_comparison(table, attribute, column, value)
-        else
-          klass.connection.case_sensitive_comparison(table, attribute, column, value)
-        end
-        klass.unscoped.tap do |scope|
-          parts = [comparison]
-          binds = [Relation::QueryAttribute.new(attribute_name, value, cast_type)]
-          scope.where_clause += Relation::WhereClause.new(parts, binds)
-        end
+        klass.unscoped.where!({ attribute => value }, options)
       end
 
       def scope_relation(record, relation)