This simple smart contract allows you to create and finalize payments. When payment is initialized, a Condition and Lockup accounts are created. Condition (String) is written into the Condition account, while funds are deposited into the Lockup account.

Then, after payer marks the condition as passed, they can invoke finalize_payment() functionality, closing and reclaiming the Condition account rent, and unlocking funds from Lockup, then transferring them to the payment recipient.

Changes since the lesson

After the lesson, I've written two tests that you can see in the /tests directory. During testing, some account mutability issues were detected (which is why testing is so important!) and fixed in the contract. The contract may slightly vary from the version written live, during the lesson.

In the second step of the escrow flow (finalize_payment instruction), funds are transferred from Lockup account to the recipient. This requires us to use the Lockup account as a signer (CpiContext::new_with_signer) - since the account must authorize changes in it's own state. I somehow skipped this part during the lesson.

We'll come back and explain all changes at the start of the next Bootcamp lesson, so you don't miss anything.