Revert "Extract `PredicateBuilder::CaseSensitiveHandler`"

This reverts commit 3a1f6fe7b4a70bf0698b0684dd48ac712c6883b6.

This commit takes the code in a direction that I am looking to avoid.
The predicate builder should be purely concerned with AST construction
as it matters to methods like `where`. Things like case sensitivity
should continue to be handled elsewhere.

1 files changed, 31 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/validations/uniqueness.rb b/activerecord/lib/active_record/validations/uniqueness.rb
index 08c4b01439..8c4930a81d 100644
--- a/activerecord/lib/active_record/validations/uniqueness.rb
+++ b/activerecord/lib/active_record/validations/uniqueness.rb
@@ -50,7 +50,37 @@ module ActiveRecord
       end
 
       def build_relation(klass, attribute, value) # :nodoc:
-        klass.unscoped.where!({ attribute => value }, options)
+        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
       end
 
       def scope_relation(record, relation)