rollback-tx

Use rollback-tx to roll back the current transaction. In most cases, you include this function in .repl files that test specific application features and failure scenarios.

Within the context of a transaction started using the begin-tx function, you can set environment data, load modules, and execute functions. You use the rollback-tx function to signal the end of a transaction block that needs to be rolled back and can be followed by additional begin-tx and commit-tx blocks.

Basic syntax

To roll back a transaction, use the following syntax:

(rollback-tx)

Arguments

The rollback-tx function does not take any arguments.

Return value

The rollback-tx function returns a string indicating the transaction identifier that has been rolled back.

Examples

The following example demonstrates how to use the rollback-tx function within a Pact REPL:

pact> (begin-tx "load module")
"Begin Tx 0 load module"
pact> (rollback-tx)
"Rollback Tx 0 load module"

In this example, a new transaction—Tx0—is started using (begin-tx), and then (rollback-tx) is called to roll back the changes from the transaction. The function returns a string indicating that "Tx 0" has been rolled back.

Note that you should only call the rollback-tx function after performing the necessary operations within a transaction. The rollback-tx function finalizes the transaction, and any changes made during the transaction are rolled back.

It's important that you always call the rollback-tx function after begin-tx and after any other transaction-related operations to properly roll back the transaction. If rollback-tx is not called, the transaction remains open and might result in unexpected behavior or inconsistencies if you are expecting changes to be undone.