Revert "Merge pull request #32075 from eileencodes/delete-default-configuration"

This reverts commit 16f279ebd4, reversing
changes made to 6c6a30a7c3.

The config can be named anything, not just default (although all
generated apps will be named default). We can't just delete configs that
don't have a database because that will break three-tier configs. Oh
well.

activerecord/lib/active_record/tasks/database_tasks.rb

@@ -315,12 +315,16 @@ module ActiveRecord
           environments << "test" if environment == "development"
 
           ActiveRecord::Base.configurations.slice(*environments).each do |configuration_environment, configuration|
+            next unless configuration["database"]
+
             yield configuration, configuration_environment
           end
         end
 
         def each_local_configuration
           ActiveRecord::Base.configurations.each_value do |configuration|
+            next unless configuration["database"]
+
             if local_database?(configuration)
               yield configuration
             else

activerecord/test/cases/tasks/database_tasks_test.rb

@@ -124,6 +124,14 @@ module ActiveRecord
       ActiveRecord::Base.connection_handler.stubs(:establish_connection)
     end
 
+    def test_ignores_configurations_without_databases
+      @configurations["development"].merge!("database" => nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:create).never
+
+      ActiveRecord::Tasks::DatabaseTasks.create_all
+    end
+
     def test_ignores_remote_databases
       @configurations["development"].merge!("host" => "my.server.tld")
       $stderr.stubs(:puts).returns(nil)
@@ -242,6 +250,14 @@ module ActiveRecord
       ActiveRecord::Base.stubs(:configurations).returns(@configurations)
     end
 
+    def test_ignores_configurations_without_databases
+      @configurations[:development].merge!("database" => nil)
+
+      ActiveRecord::Tasks::DatabaseTasks.expects(:drop).never
+
+      ActiveRecord::Tasks::DatabaseTasks.drop_all
+    end
+
     def test_ignores_remote_databases
       @configurations[:development].merge!("host" => "my.server.tld")
       $stderr.stubs(:puts).returns(nil)

railties/lib/rails/application/configuration.rb

@@ -179,7 +179,6 @@ module Rails
               values.reverse_merge!(shared)
             end
           end
-          loaded_yaml.delete("default")
           Hash.new(shared).merge(loaded_yaml)
         elsif ENV["DATABASE_URL"]
           # Value from ENV['DATABASE_URL'] is set to default database connection