PostgreSQL adapter doesn't fetch column defaults when using multiple schemas and domains

[arturopie]

Context

In our app, we have partitioned our db into multiple schemas, and each schema may use different collations for its Text columns. To accomplish this, we overrode the Text data type by creating a domain over text type for each schema, so each schema will use its own collation for every text value stored.

However, we noticed that ActiveRecord was setting to nil the attributes of new records, even though those attributes have default values in db.

Unit Test Case

Here is a unit test that show how to reproduce the bug and what the expected behaviour should be:

class DefaultDomainPartitionTest < ActiveSupport::TestCase
  class TestTable < ActiveRecord::Base ;end

  def exec sql
    ActiveRecord::Base.connection.execute sql
  end

  def setup
    ActiveRecord::Base.connection.create_table "test_tables" do |t|
      t.text "col1", :default => "some value"
    end
  end

  def test_default_in_new_schema_when_overriding_domain
    exec "CREATE SCHEMA schema_1"
    exec "CREATE DOMAIN schema_1.text AS text"

    ActiveRecord::Base.connection.schema_search_path = "schema_1, pg_catalog"

    ActiveRecord::Base.connection.create_table "test_tables" do |t|
      t.text "col1", :default => "some value"
    end

    assert_equal "some value" , TestTable.column_defaults["col1"] # it actualy returns nil
  end

  def teardown
    exec "DROP SCHEMA schema_1 CASCADE"
    exec "DROP TABLE public.test_tables"
  end
end

I already know where the problem is and how to fix it. I'd like to know what branches I should apply the patch to.

Thanks

[steveklabnik]

I'd like to know what branches I should apply the patch to.

Please do all work against master, and we'll backport as appropriate.