Migrating input formats for taxonomies with empty description

Question

I am trying to write custom migrations to migrate my Drupal 7 website to Drupal 8. I am currently using Drupal 8.7.10 and Drupal 7.61 for a copy of the production website.

I have tried to migrate description from drupal 7 source and set format as "full_html" for drupal 8.

I have read a lot of sources, for example Migrating input formats causes errors

I have used this code for migration

description/value: description
description/format: format2

and for process plugin

public function prepareRow(Row $row) {
  $row->setSourceProperty('format2', 'full_html');
}

but format didn`t saved for empty description.

How to save the format if the description is not filled?

Answer 1

The field is empty so it'll get a format set from the configured default when someone enters a description. If there's no value it doesn't need a format, because the format is purely there to say how the value should be displayed.

In theory a value of an empty string with a format attached might give a different result to a null value (the empty string might be wrapped in <p> tags for example) but this will not usually matter in practice.

So the migration is doing what is expected, by not creating an entry for an empty field value.