fixed support for DATABASE_URL for rake db tasks

- added tests to confirm establish_connection uses DATABASE_URL and
  Rails.env correctly even when no arguments are passed in.
- updated rake db tasks to support DATABASE_URL, and added tests to
  confirm correct behavior for these rake tasks.  (Removed
  establish_connection call from some tasks since in those cases
  the :environment task already made sure the function would be called)
- updated Resolver so that when it resolves the database url, it
  removes hash values with empty strings from the config spec (e.g.
  to support connection to postgresql when no username is specified).

1 files changed, 28 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/tasks/database_tasks.rb b/activerecord/lib/active_record/tasks/database_tasks.rb
index b41cc68b6a..fda51b3d76 100644
--- a/activerecord/lib/active_record/tasks/database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/database_tasks.rb
@@ -3,6 +3,8 @@ module ActiveRecord
     module DatabaseTasks # :nodoc:
       extend self
 
+      attr_writer :current_config
+
       LOCAL_HOSTS    = ['127.0.0.1', 'localhost']
 
       def register_task(pattern, task)
@@ -14,6 +16,19 @@ module ActiveRecord
       register_task(/postgresql/, ActiveRecord::Tasks::PostgreSQLDatabaseTasks)
       register_task(/sqlite/, ActiveRecord::Tasks::SQLiteDatabaseTasks)
 
+      def current_config(options = {})
+        options.reverse_merge! :env => Rails.env
+        if options.has_key?(:config)
+          @current_config = options[:config]
+        else
+          @current_config ||= if ENV['DATABASE_URL']
+                                database_url_config
+                              else
+                                ActiveRecord::Base.configurations[options[:env]]
+                              end
+        end
+      end
+
       def create(*arguments)
         configuration = arguments.first
         class_for_adapter(configuration['adapter']).new(*arguments).create
@@ -33,6 +48,10 @@ module ActiveRecord
         ActiveRecord::Base.establish_connection environment
       end
 
+      def create_database_url
+        create database_url_config
+      end
+
       def drop(*arguments)
         configuration = arguments.first
         class_for_adapter(configuration['adapter']).new(*arguments).drop
@@ -51,6 +70,10 @@ module ActiveRecord
         }
       end
 
+      def drop_database_url
+        drop database_url_config
+      end
+
       def charset_current(environment = Rails.env)
         charset ActiveRecord::Base.configurations[environment]
       end
@@ -87,6 +110,11 @@ module ActiveRecord
 
       private
 
+      def database_url_config
+        @database_url_config ||=
+               ConnectionAdapters::ConnectionSpecification::Resolver.new(ENV["DATABASE_URL"], {}).spec.config.stringify_keys
+      end
+
       def class_for_adapter(adapter)
         key = @tasks.keys.detect { |pattern| adapter[pattern] }
         @tasks[key]