#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.

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -78,7 +78,7 @@ 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

activerecord/test/cases/adapters/postgresql/schema_test.rb

@@ -72,7 +72,7 @@ class SchemaTest < ActiveRecord::TestCase
   end
 
   def test_schema_names
-    assert_equal ["public", "test_schema", "test_schema2"], @connection.schema_names
+    assert_equal ["public", "schema_1", "test_schema", "test_schema2"], @connection.schema_names
   end
 
   def test_create_schema

activerecord/test/cases/defaults_test.rb

@@ -109,3 +109,43 @@ 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

activerecord/test/schema/postgresql_specific_schema.rb

@@ -12,6 +12,8 @@ ActiveRecord::Schema.define do
 
   execute 'DROP FUNCTION IF EXISTS partitioned_insert_trigger()'
 
+  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
@@ -37,7 +39,12 @@ 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,