From 1f432c54658cf54608a6e37b70b8dc8e40521502 Mon Sep 17 00:00:00 2001
From: Dmitry Lavrov <lavrovdv@gmail.com>
Date: Thu, 27 Mar 2014 15:29:20 +0300
Subject: Treat blank UUID values as nil

---
 activerecord/CHANGELOG.md                                        | 8 ++++++++
 .../lib/active_record/connection_adapters/postgresql/oid.rb      | 9 ++++++++-
 activerecord/test/cases/adapters/postgresql/uuid_test.rb         | 5 +++++
 3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index acd3d395c5..f7718394af 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,11 @@
+*   Treat blank UUID values as `nil`.
+
+    Example:
+
+        Sample.new(uuid_field: '') #=> <Sample id: nil, uuid_field: nil>
+
+    *Dmitry Lavrov*
+
 *   Enable support for materialized views on PostgreSQL >= 9.3.
 
     *Dave Lee*
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
index 57bdc3bb19..9e898015a6 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid.rb
@@ -330,6 +330,13 @@ This is not reliable and will be removed in the future.
           end
         end
 
+        class Uuid < Type
+          def type; :uuid end
+          def type_cast(value)
+            value.presence
+          end
+        end
+
         class TypeMap
           def initialize
             @mapping = {}
@@ -418,10 +425,10 @@ This is not reliable and will be removed in the future.
         register_type 'json', OID::Json.new
         register_type 'cidr', OID::Cidr.new
         register_type 'inet', OID::Inet.new
+        register_type 'uuid', OID::Uuid.new
         register_type 'xml', SpecializedString.new(:xml)
         register_type 'tsvector', SpecializedString.new(:tsvector)
         register_type 'macaddr', SpecializedString.new(:macaddr)
-        register_type 'uuid', SpecializedString.new(:uuid)
         register_type 'citext', SpecializedString.new(:citext)
         register_type 'ltree', SpecializedString.new(:ltree)
 
diff --git a/activerecord/test/cases/adapters/postgresql/uuid_test.rb b/activerecord/test/cases/adapters/postgresql/uuid_test.rb
index f79a7a598b..9e03ea6bee 100644
--- a/activerecord/test/cases/adapters/postgresql/uuid_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/uuid_test.rb
@@ -50,6 +50,11 @@ class PostgresqlUUIDTest < ActiveRecord::TestCase
     assert_not column.array
   end
 
+  def test_treat_blank_uuid_as_nil
+    UUIDType.create! guid: ''
+    assert_equal(nil, UUIDType.last.guid)
+  end
+
   def test_uuid_formats
     ["A0EEBC99-9C0B-4EF8-BB6D-6BB9BD380A11",
      "{a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11}",
-- 
cgit v1.2.3