Don't or didn't?

Question

Don't worry if you don't finish the report. or Don't worry if you didn't finish the report. which one is correct and why?

Answer 1

If you are telling them about the future then use don't and if you are talking about the past then use didn't

Examples:

Don't worry if you didn't finish the assignment which was due yesterday.

Don't worry if you don't finish the assignment by tomorrow.