Rolling back a failed Rails migration

Question

How do you roll back a failed rails migration? I would expect that rake db:rollback would undo the failed migration, but no, it rolls back the previous migratio

Answer 1

Alejandro Babio's answer above provides the best current answer.

One additional detail I want to add:

When the myfailedmigration migration fails, it is not considered as applied, and this can be verified by running rake db:migrate:status, which would show output similar to the following:

$  rake db:migrate:status
database: sample_app_dev

 Status   Migration ID    Migration Name
--------------------------------------------------
   up      20130206203115  Create users
   ...
   ...
   down    20150501173156  Test migration

The residual effect of add_column :assets, :test, :integer being executed on the failed migration will have to be reversed at the database level with a alter table assets drop column test; query.