#7914 get default value when type uses schema name

PostgreSQL adapter properly parses default values when using multiple
schemas and domains.

When using domains across schemas, PostgresSQL prefixes the type of the
default value with the name of the schema where that type (or domain) is.

For example, this query:
```
SELECT a.attname, d.adsrc
FROM pg_attribute a LEFT JOIN pg_attrdef d
ON a.attrelid = d.adrelid AND a.attnum = d.adnum
WHERE a.attrelid = "defaults"'::regclass
AND a.attnum > 0 AND NOT a.attisdropped
ORDER BY a.attnum;
```

could return something like "'<default_value>'::pg_catalog.text" or
"(''<default_value>'::pg_catalog.text)::text" for the text columns with
defaults.

I modified the regexp used to parse this value so that it ignores
anything between ':: and \b(?:character varying|bpchar|text), and it
allows to have optional parens like in the above second example.

4 files changed, 54 insertions, 2 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index ef2b112b34..402c296aee 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,5 +1,10 @@
 ## Rails 3.2.9 (unreleased)
 
+*   PostgreSQL adapter correctly fetches default values when using
+    multiple schemas and domains in a db. Fixes #7914
+
+    *Arturo Pie*
+
 *   Fix deprecation notice when loading a collection association that
     selects columns from other tables, if a new record was previously
     built using that association.
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index ca9a29a5cb..e34acd8dae 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -145,7 +145,7 @@ module ActiveRecord
             when /\A\(?(-?\d+(\.\d*)?\)?)\z/
               $1
             # Character types
-            when /\A'(.*)'::(?:character varying|bpchar|text)\z/m
+            when /\A\(?'(.*)'::.*\b(?:character varying|bpchar|text)\z/m
               $1
             # Character types (8.1 formatting)
             when /\AE'(.*)'::(?:character varying|bpchar|text)\z/m
diff --git a/activerecord/test/cases/defaults_test.rb b/activerecord/test/cases/defaults_test.rb
index b3a281d960..c63553ed51 100644
--- a/activerecord/test/cases/defaults_test.rb
+++ b/activerecord/test/cases/defaults_test.rb
@@ -110,3 +110,43 @@ if current_adapter?(:MysqlAdapter) or current_adapter?(:Mysql2Adapter)
     end
   end
 end
+
+if current_adapter?(:PostgreSQLAdapter)
+  class DefaultsUsingMultipleSchemasAndDomainTest < ActiveSupport::TestCase
+    def setup
+      @connection = ActiveRecord::Base.connection
+
+      @old_search_path = @connection.schema_search_path
+      @connection.schema_search_path = "schema_1, pg_catalog"
+      @connection.create_table "defaults" do |t|
+        t.text "text_col", :default => "some value"
+        t.string "string_col", :default => "some value"
+      end
+      Default.reset_column_information
+    end
+
+    def test_text_defaults_in_new_schema_when_overriding_domain
+      assert_equal "some value", Default.new.text_col, "Default of text column was not correctly parse"
+    end
+
+    def test_string_defaults_in_new_schema_when_overriding_domain
+      assert_equal "some value", Default.new.string_col, "Default of string column was not correctly parse"
+    end
+
+    def test_bpchar_defaults_in_new_schema_when_overriding_domain
+      @connection.execute "ALTER TABLE defaults ADD bpchar_col bpchar DEFAULT 'some value'"
+      Default.reset_column_information
+      assert_equal "some value", Default.new.bpchar_col, "Default of bpchar column was not correctly parse"
+    end
+
+    def test_text_defaults_after_updating_column_default
+      @connection.execute "ALTER TABLE defaults ALTER COLUMN text_col SET DEFAULT 'some text'::schema_1.text"
+      assert_equal "some text", Default.new.text_col, "Default of text column was not correctly parse after updating default using '::text' since postgreSQL will add parens to the default in db"
+    end
+
+    def teardown
+      @connection.schema_search_path = @old_search_path
+      Default.reset_column_information
+    end
+  end
+end
diff --git a/activerecord/test/schema/postgresql_specific_schema.rb b/activerecord/test/schema/postgresql_specific_schema.rb
index 5cf9a207f3..34e24b5a2e 100644
--- a/activerecord/test/schema/postgresql_specific_schema.rb
+++ b/activerecord/test/schema/postgresql_specific_schema.rb
@@ -10,6 +10,8 @@ ActiveRecord::Schema.define do
   execute "ALTER TABLE companies ALTER COLUMN id SET DEFAULT nextval('companies_nonstd_seq')"
   execute 'DROP SEQUENCE IF EXISTS companies_id_seq'
 
+  execute "DROP SCHEMA IF EXISTS schema_1 CASCADE"
+
   %w(accounts_id_seq developers_id_seq projects_id_seq topics_id_seq customers_id_seq orders_id_seq).each do |seq_name|
     execute "SELECT setval('#{seq_name}', 100)"
   end
@@ -35,7 +37,12 @@ ActiveRecord::Schema.define do
 );
 _SQL
 
-    execute <<_SQL
+  execute "CREATE SCHEMA schema_1"
+  execute "CREATE DOMAIN schema_1.text AS text"
+  execute "CREATE DOMAIN schema_1.varchar AS varchar"
+  execute "CREATE DOMAIN schema_1.bpchar AS bpchar"
+
+  execute <<_SQL
   CREATE TABLE geometrics (
     id serial primary key,
     a_point point,