Correctly ignore `case_sensitive` for UUID uniqueness validation

I think we should deprecate this behavior and just error if you tell us
to do a case insensitive comparison for types which are not case
sensitive. Partially reverts 35592307

Fixes #18195

1 files changed, 17 insertions, 0 deletions

diff --git a/activerecord/test/cases/adapters/postgresql/uuid_test.rb b/activerecord/test/cases/adapters/postgresql/uuid_test.rb
index 3c967d73da..d5d2dd16e2 100644
--- a/activerecord/test/cases/adapters/postgresql/uuid_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/uuid_test.rb
@@ -116,6 +116,23 @@ class PostgresqlUUIDTest < ActiveRecord::TestCase
     output = dump_table_schema "uuid_data_type"
     assert_match %r{t.uuid "guid"}, output
   end
+
+  def test_uniqueness_validation_ignores_uuid
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "uuid_data_type"
+      validates :guid, uniqueness: { case_sensitive: false }
+
+      def self.name
+        "UUIDType"
+      end
+    end
+
+    record = klass.create!(guid: "a0ee-bc99-9c0b-4ef8-bb6d-6bb9-bd38-0a11")
+    duplicate = klass.new(guid: record.guid)
+
+    assert record.guid.present? # Ensure we actually are testing a UUID
+    assert_not duplicate.valid?
+  end
 end
 
 class PostgresqlLargeKeysTest < ActiveRecord::TestCase