Method: Migr8::RepositoryOperation#downgrade

Defined in:

lib/migr8.rb

#downgrade(n) ⇒ Object

# File 'lib/migr8.rb', line 488

def downgrade(n)
  migs_hist, migs_dict = _get_migrations_hist_and_applied()
  ## index of current version
  curr = migs_hist.rindex {|mig| mig.applied? }
  ## error when unapplied older version exists in target migrations
  migs_applied = curr ? migs_hist[0..curr] : []
  if curr
    j = migs_applied.index {|mig| ! mig.applied? }
    raise MigrationError.new("apply #{migs_applied[j].version} at first.") if j && j < curr
  end
  ## unapply n migrations
  migs_to_unapply = n && n < migs_applied.length ? migs_applied[-n..-1] \
                                                 : migs_applied
  if migs_to_unapply.empty?
    puts "## (nothing to unapply)"
  else
    #migs_to_unapply.reverse_each do |mig|
    #  puts "## unapplying #{mig.version}  \# [#{mig.author}] #{mig.desc}"
    #  @repo.unapply_migration(mig)
    #end
    @repo.unapply_migrations(migs_to_unapply.reverse())
  end
end