When running `php bin/console ezplatform:migrate:legacy_matrix` (https://github.com/ezsystems/ezplatform-matrix-fieldtype/blob/107e3588eebb7ab78033c64e549cefb01146c105/src/bundle/Command/MigrateLegacyMatrixCommand.php), the script errors out if there are 0 instances of the content object / content object attribute:

[Symfony\Component\Console\Exception\LogicException]
Unable to display the estimated time if the maximum number of steps is not set.