Migration: match empty text

In a migration, how do we support the matching of an empty text, to be able to handle the empty case differently? For instance, create an entry only when there the source text is not empty?

We don’t support this directly.
The only options to inspect a text value is with a regexp or the compare text of the boolean expression.
The second option allows matching with static values, but like al other conditional expressions, requires a stategroup.