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).

7 files changed, 275 insertions, 32 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/connection_specification.rb b/activerecord/lib/active_record/connection_adapters/connection_specification.rb
index dd40351a38..b9a61f7d91 100644
--- a/activerecord/lib/active_record/connection_adapters/connection_specification.rb
+++ b/activerecord/lib/active_record/connection_adapters/connection_specification.rb
@@ -72,7 +72,7 @@ module ActiveRecord
                    :port     => config.port,
                    :database => config.path.sub(%r{^/},""),
                    :host     => config.host }
-          spec.reject!{ |_,value| !value }
+          spec.reject!{ |_,value| value.blank? }
           if config.query
             options = Hash[config.query.split("&").map{ |pair| pair.split("=") }].symbolize_keys
             spec.merge!(options)
diff --git a/activerecord/lib/active_record/railties/databases.rake b/activerecord/lib/active_record/railties/databases.rake
index ae24542521..bcb26f72c8 100644
--- a/activerecord/lib/active_record/railties/databases.rake
+++ b/activerecord/lib/active_record/railties/databases.rake
@@ -18,9 +18,13 @@ db_namespace = namespace :db do
     end
   end
 
-  desc 'Create the database from config/database.yml for the current Rails.env (use db:create:all to create all dbs in the config)'
+  desc 'Create the database from DATABASE_URL or config/database.yml for the current Rails.env (use db:create:all to create all dbs in the config)'
   task :create => [:load_config] do
-    ActiveRecord::Tasks::DatabaseTasks.create_current
+    if ENV['DATABASE_URL']
+      ActiveRecord::Tasks::DatabaseTasks.create_database_url
+    else
+      ActiveRecord::Tasks::DatabaseTasks.create_current
+    end
   end
 
   namespace :drop do
@@ -29,9 +33,13 @@ db_namespace = namespace :db do
     end
   end
 
-  desc 'Drops the database for the current Rails.env (use db:drop:all to drop all databases)'
+  desc 'Drops the database using DATABASE_URL or the current Rails.env (use db:drop:all to drop all databases)'
   task :drop => [:load_config] do
-    ActiveRecord::Tasks::DatabaseTasks.drop_current
+    if ENV['DATABASE_URL']
+      ActiveRecord::Tasks::DatabaseTasks.drop_database_url
+    else
+      ActiveRecord::Tasks::DatabaseTasks.drop_current
+    end
   end
 
   desc "Migrate the database (options: VERSION=x, VERBOSE=false, SCOPE=blog)."
@@ -88,8 +96,6 @@ db_namespace = namespace :db do
 
     desc 'Display status of migrations'
     task :status => [:environment, :load_config] do
-      config = ActiveRecord::Base.configurations[Rails.env]
-      ActiveRecord::Base.establish_connection(config)
       unless ActiveRecord::Base.connection.table_exists?(ActiveRecord::Migrator.schema_migrations_table_name)
         puts 'Schema migrations table does not exist yet.'
         next  # means "return" for rake task
@@ -110,7 +116,7 @@ db_namespace = namespace :db do
         ['up', version, '********** NO FILE **********']
       end
       # output
-      puts "\ndatabase: #{config['database']}\n\n"
+      puts "\ndatabase: #{ActiveRecord::Base.connection_config[:database]}\n\n"
       puts "#{'Status'.center(8)}  #{'Migration ID'.ljust(14)}  Migration Name"
       puts "-" * 50
       (db_list + file_list).sort_by {|migration| migration[1]}.each do |migration|
@@ -186,7 +192,6 @@ db_namespace = namespace :db do
     task :load => [:environment, :load_config] do
       require 'active_record/fixtures'
 
-      ActiveRecord::Base.establish_connection(Rails.env)
       base_dir     = File.join [Rails.root, ENV['FIXTURES_PATH'] || %w{test fixtures}].flatten
       fixtures_dir = File.join [base_dir, ENV['FIXTURES_DIR']].compact
 
@@ -225,7 +230,6 @@ db_namespace = namespace :db do
       require 'active_record/schema_dumper'
       filename = ENV['SCHEMA'] || "#{Rails.root}/db/schema.rb"
       File.open(filename, "w:utf-8") do |file|
-        ActiveRecord::Base.establish_connection(Rails.env)
         ActiveRecord::SchemaDumper.dump(ActiveRecord::Base.connection, file)
       end
       db_namespace['schema:dump'].reenable
@@ -277,22 +281,22 @@ db_namespace = namespace :db do
 
     desc 'Dump the database structure to db/structure.sql. Specify another file with DB_STRUCTURE=db/my_structure.sql'
     task :dump => [:environment, :load_config] do
-      abcs = ActiveRecord::Base.configurations
       filename = ENV['DB_STRUCTURE'] || File.join(Rails.root, "db", "structure.sql")
-      case abcs[Rails.env]['adapter']
+      current_config = ActiveRecord::Tasks::DatabaseTasks.current_config
+      case current_config['adapter']
       when /mysql/, /postgresql/, /sqlite/
-        ActiveRecord::Tasks::DatabaseTasks.structure_dump(abcs[Rails.env], filename)
+        ActiveRecord::Tasks::DatabaseTasks.structure_dump(current_config, filename)
       when 'oci', 'oracle'
-        ActiveRecord::Base.establish_connection(abcs[Rails.env])
+        ActiveRecord::Base.establish_connection(current_config)
         File.open(filename, "w:utf-8") { |f| f << ActiveRecord::Base.connection.structure_dump }
       when 'sqlserver'
-        `smoscript -s #{abcs[Rails.env]['host']} -d #{abcs[Rails.env]['database']} -u #{abcs[Rails.env]['username']} -p #{abcs[Rails.env]['password']} -f #{filename} -A -U`
+        `smoscript -s #{current_config['host']} -d #{current_config['database']} -u #{current_config['username']} -p #{current_config['password']} -f #{filename} -A -U`
       when "firebird"
-        set_firebird_env(abcs[Rails.env])
-        db_string = firebird_db_string(abcs[Rails.env])
+        set_firebird_env(current_config)
+        db_string = firebird_db_string(current_config)
         sh "isql -a #{db_string} > #{filename}"
       else
-        raise "Task not supported by '#{abcs[Rails.env]["adapter"]}'"
+        raise "Task not supported by '#{current_config["adapter"]}'"
       end
 
       if ActiveRecord::Base.connection.supports_migrations?
@@ -303,26 +307,24 @@ db_namespace = namespace :db do
 
     # desc "Recreate the databases from the structure.sql file"
     task :load => [:environment, :load_config] do
-      env = ENV['RAILS_ENV'] || 'test'
-
-      abcs = ActiveRecord::Base.configurations
+      current_config = ActiveRecord::Tasks::DatabaseTasks.current_config(:env => (ENV['RAILS_ENV'] || 'test'))
       filename = ENV['DB_STRUCTURE'] || File.join(Rails.root, "db", "structure.sql")
-      case abcs[env]['adapter']
+      case current_config['adapter']
       when /mysql/, /postgresql/, /sqlite/
-        ActiveRecord::Tasks::DatabaseTasks.structure_load(abcs[env], filename)
+        ActiveRecord::Tasks::DatabaseTasks.structure_load(current_config, filename)
       when 'sqlserver'
-        `sqlcmd -S #{abcs[env]['host']} -d #{abcs[env]['database']} -U #{abcs[env]['username']} -P #{abcs[env]['password']} -i #{filename}`
+        `sqlcmd -S #{current_config['host']} -d #{current_config['database']} -U #{current_config['username']} -P #{current_config['password']} -i #{filename}`
       when 'oci', 'oracle'
-        ActiveRecord::Base.establish_connection(abcs[env])
+        ActiveRecord::Base.establish_connection(current_config)
         IO.read(filename).split(";\n\n").each do |ddl|
           ActiveRecord::Base.connection.execute(ddl)
         end
       when 'firebird'
-        set_firebird_env(abcs[env])
-        db_string = firebird_db_string(abcs[env])
+        set_firebird_env(current_config)
+        db_string = firebird_db_string(current_config)
         sh "isql -i #{filename} #{db_string}"
       else
-        raise "Task not supported by '#{abcs[env]['adapter']}'"
+        raise "Task not supported by '#{current_config['adapter']}'"
       end
     end
 
@@ -353,10 +355,10 @@ db_namespace = namespace :db do
     # desc "Recreate the test database from an existent structure.sql file"
     task :load_structure => 'db:test:purge' do
       begin
-        old_env, ENV['RAILS_ENV'] = ENV['RAILS_ENV'], 'test'
+        ActiveRecord::Tasks::DatabaseTasks.current_config(:config => ActiveRecord::Base.configurations['test'])
         db_namespace["structure:load"].invoke
       ensure
-        ENV['RAILS_ENV'] = old_env
+        ActiveRecord::Tasks::DatabaseTasks.current_config(:config => nil)
       end
     end
 
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]
diff --git a/activerecord/test/cases/connection_specification/resolver_test.rb b/activerecord/test/cases/connection_specification/resolver_test.rb
index 673a2b2b88..434d2b7ba5 100644
--- a/activerecord/test/cases/connection_specification/resolver_test.rb
+++ b/activerecord/test/cases/connection_specification/resolver_test.rb
@@ -13,7 +13,6 @@ module ActiveRecord
           spec = resolve 'mysql://foo?encoding=utf8'
           assert_equal({
             :adapter  => "mysql",
-            :database => "",
             :host     => "foo",
             :encoding => "utf8" }, spec)
         end
@@ -33,7 +32,6 @@ module ActiveRecord
           spec = resolve 'mysql://foo:123?encoding=utf8'
           assert_equal({
             :adapter  => "mysql",
-            :database => "",
             :port     => 123,
             :host     => "foo",
             :encoding => "utf8" }, spec)
diff --git a/railties/CHANGELOG.md b/railties/CHANGELOG.md
index e889f0c23c..f4f81f1128 100644
--- a/railties/CHANGELOG.md
+++ b/railties/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Fixed support for DATABASE_URL environment variable for rake db tasks. *Grace Liu*
+
 *   rails dbconsole now can use SSL for MySQL. The database.yml options sslca, sslcert, sslcapath, sslcipher,
     and sslkey now affect rails dbconsole. *Jim Kingdon and Lars Petrus*
 
diff --git a/railties/test/application/initializers/frameworks_test.rb b/railties/test/application/initializers/frameworks_test.rb
index d3bbac811c..fbce97e1a9 100644
--- a/railties/test/application/initializers/frameworks_test.rb
+++ b/railties/test/application/initializers/frameworks_test.rb
@@ -195,5 +195,37 @@ module ApplicationTests
         assert !ActiveRecord::Base.connection.schema_cache.tables["posts"]
       }
     end
+
+    test "active record establish_connection uses Rails.env if DATABASE_URL is not set" do
+      begin
+        require "#{app_path}/config/environment"
+        orig_database_url = ENV.delete("DATABASE_URL")
+        orig_rails_env, Rails.env = Rails.env, 'development'
+        ActiveRecord::Base.establish_connection
+        assert ActiveRecord::Base.connection
+        assert_match /#{ActiveRecord::Base.configurations[Rails.env]['database']}/, ActiveRecord::Base.connection_config[:database]
+      ensure
+        ActiveRecord::Base.remove_connection
+        ENV["DATABASE_URL"] = orig_database_url if orig_database_url
+        Rails.env = orig_rails_env if orig_rails_env
+      end
+    end
+
+    test "active record establish_connection uses DATABASE_URL even if Rails.env is set" do
+      begin
+        require "#{app_path}/config/environment"
+        orig_database_url = ENV.delete("DATABASE_URL")
+        orig_rails_env, Rails.env = Rails.env, 'development'
+        database_url_db_name = "db/database_url_db.sqlite3"
+        ENV["DATABASE_URL"] = "sqlite3://:@localhost/#{database_url_db_name}"
+        ActiveRecord::Base.establish_connection
+        assert ActiveRecord::Base.connection
+        assert_match /#{database_url_db_name}/, ActiveRecord::Base.connection_config[:database]
+      ensure
+        ActiveRecord::Base.remove_connection
+        ENV["DATABASE_URL"] = orig_database_url if orig_database_url
+        Rails.env = orig_rails_env if orig_rails_env
+      end
+    end
   end
 end
diff --git a/railties/test/application/rake/dbs_test.rb b/railties/test/application/rake/dbs_test.rb
new file mode 100644
index 0000000000..52c07cee9f
--- /dev/null
+++ b/railties/test/application/rake/dbs_test.rb
@@ -0,0 +1,181 @@
+require "isolation/abstract_unit"
+
+module ApplicationTests
+  module RakeTests
+    class RakeDbsTest < ActiveSupport::TestCase
+      include ActiveSupport::Testing::Isolation
+
+      def setup
+        build_app
+        boot_rails
+        FileUtils.rm_rf("#{app_path}/config/environments")
+      end
+
+      def teardown
+        teardown_app
+      end
+
+      def database_url_db_name
+        "db/database_url_db.sqlite3"
+      end
+
+      def set_database_url
+        ENV['DATABASE_URL'] = "sqlite3://:@localhost/#{database_url_db_name}"
+      end
+
+      def expected
+        @expected ||= {}
+      end
+
+      def db_create_and_drop
+        Dir.chdir(app_path) do
+          output = `bundle exec rake db:create`
+          assert_equal output, ""
+          assert File.exists?(expected[:database])
+          assert_equal expected[:database],
+                        ActiveRecord::Base.connection_config[:database]
+          output = `bundle exec rake db:drop`
+          assert_equal output, ""
+          assert !File.exists?(expected[:database])
+        end
+      end
+
+      test 'db:create and db:drop without database url' do
+        require "#{app_path}/config/environment"
+        expected[:database] = ActiveRecord::Base.configurations[Rails.env]['database']
+        db_create_and_drop
+       end
+
+      test 'db:create and db:drop with database url' do
+        require "#{app_path}/config/environment"
+        set_database_url
+        expected[:database] = database_url_db_name
+        db_create_and_drop
+      end
+
+      def db_migrate_and_status
+        Dir.chdir(app_path) do
+          `rails generate model book title:string`
+          `bundle exec rake db:migrate`
+          output = `bundle exec rake db:migrate:status`
+          assert_match(/database:\s+\S+#{expected[:database]}/, output)
+          assert_match(/up\s+\d{14}\s+Create books/, output)
+        end
+      end
+
+      test 'db:migrate and db:migrate:status without database_url' do
+        require "#{app_path}/config/environment"
+        expected[:database] = ActiveRecord::Base.configurations[Rails.env]['database']
+        db_migrate_and_status
+      end
+
+      test 'db:migrate and db:migrate:status with database_url' do
+        require "#{app_path}/config/environment"
+        set_database_url
+        expected[:database] = database_url_db_name
+        db_migrate_and_status
+      end
+
+      def db_schema_dump
+        Dir.chdir(app_path) do
+          `rails generate model book title:string`
+          `rake db:migrate`
+          `rake db:schema:dump`
+          schema_dump = File.read("db/schema.rb")
+          assert_match(/create_table \"books\"/, schema_dump)
+        end
+      end
+
+      test 'db:schema:dump without database_url' do
+        db_schema_dump
+      end
+
+      test 'db:schema:dump with database_url' do
+        set_database_url
+        db_schema_dump
+      end
+
+      def db_fixtures_load
+        Dir.chdir(app_path) do
+          `rails generate model book title:string`
+          `bundle exec rake db:migrate`
+          `bundle exec rake db:fixtures:load`
+          assert_match /#{expected[:database]}/,
+                    ActiveRecord::Base.connection_config[:database]
+          require "#{app_path}/app/models/book"
+          assert_equal 2, Book.count
+        end
+      end
+
+      test 'db:fixtures:load without database_url' do
+        require "#{app_path}/config/environment"
+        expected[:database] =  ActiveRecord::Base.configurations[Rails.env]['database']
+        db_fixtures_load
+      end
+
+      test 'db:fixtures:load with database_url' do
+        require "#{app_path}/config/environment"
+        set_database_url
+        expected[:database] = database_url_db_name
+        db_fixtures_load
+      end
+
+      def db_structure_dump_and_load
+        Dir.chdir(app_path) do
+          `rails generate model book title:string`
+          `bundle exec rake db:migrate`
+          `bundle exec rake db:structure:dump`
+          structure_dump = File.read("db/structure.sql")
+          assert_match(/CREATE TABLE \"books\"/, structure_dump)
+          `bundle exec rake db:drop`
+          `bundle exec rake db:structure:load`
+          assert_match /#{expected[:database]}/,
+                        ActiveRecord::Base.connection_config[:database]
+          require "#{app_path}/app/models/book"
+          #if structure is not loaded correctly, exception would be raised
+          assert Book.count, 0
+        end
+      end
+
+      test 'db:structure:dump and db:structure:load without database_url' do
+        require "#{app_path}/config/environment"
+        expected[:database] =  ActiveRecord::Base.configurations[Rails.env]['database']
+        db_structure_dump_and_load
+      end
+
+      test 'db:structure:dump and db:structure:load with database_url' do
+        require "#{app_path}/config/environment"
+        set_database_url
+        expected[:database] = database_url_db_name
+        db_structure_dump_and_load
+      end
+
+      def db_test_load_structure
+        Dir.chdir(app_path) do
+          `rails generate model book title:string`
+          `bundle exec rake db:migrate`
+          `bundle exec rake db:structure:dump`
+          `bundle exec rake db:test:load_structure`
+          ActiveRecord::Base.configurations = Rails.application.config.database_configuration
+          ActiveRecord::Base.establish_connection 'test'
+          require "#{app_path}/app/models/book"
+          #if structure is not loaded correctly, exception would be raised
+          assert Book.count, 0
+          assert_match /#{ActiveRecord::Base.configurations['test']['database']}/,
+                        ActiveRecord::Base.connection_config[:database]
+        end
+      end
+
+      test 'db:test:load_structure without database_url' do
+        require "#{app_path}/config/environment"
+        db_test_load_structure
+      end
+
+      test 'db:test:load_structure with database_url' do
+        require "#{app_path}/config/environment"
+        set_database_url
+        db_test_load_structure
+      end
+    end
+  end
+end
\ No newline at end of file