Upvote:4
This situation will have no effect when applying for a new Schengen visa.
You were refused entry to Croatia (at a time when Croatia was not a member of the Schengen Area) since you had used your single entry visa and therefore could not return to the Schengen Area after your visit to Croatia.
The exit stamp from the Schengen Area was canceled/voided as if it never happened.
You broke no Schengen Area rules, so no warning in the Schengen Information system will exist.