From 776af48acb1035e70a326609ec5e5b632ef0c2c5 Mon Sep 17 00:00:00 2001
From: Aaron Patterson <aaron.patterson@gmail.com>
Date: Mon, 19 Dec 2011 21:16:23 -0800
Subject: [PATCH] PostgreSQL hstore types are automatically deserialized from
 the database.

---
 activerecord/CHANGELOG.md                        |  4 ++++
 .../active_record/connection_adapters/column.rb  |  2 ++
 .../connection_adapters/postgresql_adapter.rb    |  4 ++++
 .../cases/adapters/postgresql/hstore_test.rb     | 16 ++++++++++++++++
 4 files changed, 26 insertions(+)

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 348873d7597b1..6ea8ce129a375 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,7 @@
+## Rails 4.0.0 (unreleased) ##
+
+*   PostgreSQL hstore types are automatically deserialized from the database.
+
 ## Rails 3.2.0 (unreleased) ##
 
 *   Added ability to run migrations only for given scope, which allows
diff --git a/activerecord/lib/active_record/connection_adapters/column.rb b/activerecord/lib/active_record/connection_adapters/column.rb
index 0214154c51c9f..6aa4a2c5b38f2 100644
--- a/activerecord/lib/active_record/connection_adapters/column.rb
+++ b/activerecord/lib/active_record/connection_adapters/column.rb
@@ -83,6 +83,7 @@ def type_cast(value)
         when :date                 then klass.value_to_date(value)
         when :binary               then klass.binary_to_string(value)
         when :boolean              then klass.value_to_boolean(value)
+        when :hstore               then klass.cast_hstore(value)
         else value
         end
       end
@@ -100,6 +101,7 @@ def type_cast_code(var_name)
         when :date                 then "#{klass}.value_to_date(#{var_name})"
         when :binary               then "#{klass}.binary_to_string(#{var_name})"
         when :boolean              then "#{klass}.value_to_boolean(#{var_name})"
+        when :hstore               then "#{klass}.cast_hstore(#{var_name})"
         else var_name
         end
       end
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 9802bac87b631..563f98dc5e9b1 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -49,6 +49,10 @@ def string_to_time(string)
             super
           end
         end
+
+        def cast_hstore(string)
+          Hash[[string.split('=>').map { |k| k[1...-1] }]]
+        end
       end
       # :startdoc:
 
diff --git a/activerecord/test/cases/adapters/postgresql/hstore_test.rb b/activerecord/test/cases/adapters/postgresql/hstore_test.rb
index 155c6f593bb2c..aa3bde09d8294 100644
--- a/activerecord/test/cases/adapters/postgresql/hstore_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/hstore_test.rb
@@ -21,4 +21,20 @@ def test_column
     assert column
     assert_equal :hstore, column.type
   end
+
+  def test_type_cast_hstore
+    column = Hstore.columns.find { |c| c.name == 'tags' }
+    assert column
+
+    data = "\"1\"=>\"2\""
+    hash = column.class.cast_hstore data
+    assert_equal({'1' => '2'}, hash)
+    assert_equal({'1' => '2'}, column.type_cast(data))
+  end
+
+  def test_select
+    @connection.execute "insert into hstores (tags) VALUES ('1=>2')"
+    x = Hstore.find :first
+    assert_equal({'1' => '2'}, x.tags)
+  end
 end