Corrections

Nothing is edited: a correction is a reversal that mirrors the wrong entry exactly, booked in an open period.

What to call

reversal(id, key, on) builds the draft that reverses entry id; record it with record. Entry::reverses(target) marks a hand-built draft as a reversal.

Nothing is edited

An entry, once recorded, is never changed or deleted; the API has no call for either. A wrong booking is undone by a second entry, the reversal, and the right one is booked by a third. All three stay in the books and can be proven.

reversal returns a draft with the target's postings in the same order — same accounts, amounts, currencies, layers and dimensions — with every side swapped. Building it checks nothing; recording it checks everything.

use doubleentry::prelude::*;

let mut books = Journal::new(LedgerId::new("example.com/acme")?);
books.declare_currency(EUR, 2, date!("2026-01-01"))?;
books.open("Assets:Cash", AccountKind::Asset, date!("2026-01-01"))?;
books.open("Expenses:Rent", AccountKind::Expense, date!("2026-01-01"))?;
books.open("Expenses:Office", AccountKind::Expense, date!("2026-01-01"))?;
books.define_months(2026, 3..=3)?;

let wrong = books.record(
    Entry::new("bill-77", date!("2026-03-15"))
        .debit("Expenses:Rent", amount!("420.00"), EUR)
        .credit("Assets:Cash", amount!("420.00"), EUR),
)?;

let half = Entry::new("bill-77-half", date!("2026-03-16"))
    .reverses(wrong.id)
    .debit("Assets:Cash", amount!("210.00"), EUR)
    .credit("Expenses:Rent", amount!("210.00"), EUR);
assert_eq!(books.record(half).unwrap_err().code(), Some(403)); // not a mirror

books.record(books.reversal(wrong.id, "bill-77-rev", date!("2026-03-16"))?)?;
books.record(
    Entry::new("bill-77-fix", date!("2026-03-16"))
        .debit("Expenses:Office", amount!("420.00"), EUR)
        .credit("Assets:Cash", amount!("420.00"), EUR),
)?;
let rent = books.balance("Expenses:Rent", EUR, &BalanceQuery::all())?;
assert_eq!(rent.to_string(), "dr 420.00 cr 420.00 net 0.00 (2 postings)");

let twice = books.reversal(wrong.id, "bill-77-rev-2", date!("2026-03-17"))?;
assert_eq!(books.record(twice).unwrap_err().code(), Some(401)); // AlreadyReversed

The rules

A reversal is checked in the references stage, in this order:

An entry cannot both reverse and act on a hold (144). Otherwise a reversal is an ordinary entry — open period, open accounts, limits — and can itself be reversed. A partial or reordered hand-built reversal is refused with 403, naming the first posting that differs.

Correcting a sealed period

Nothing can be booked into a sealed period (301). A mistake found later is reversed in an open period; the original stays where it was, and each seal proves what the books said at the time.

use doubleentry::prelude::*;

let mut books = Journal::new(LedgerId::new("example.com/acme")?);
books.declare_currency(EUR, 2, date!("2026-01-01"))?;
books.open("Assets:Cash", AccountKind::Asset, date!("2026-01-01"))?;
books.open("Expenses:Rent", AccountKind::Expense, date!("2026-01-01"))?;
books.define_months(2026, 3..=4)?;
let wrong = books.record(
    Entry::new("bill-77", date!("2026-03-15"))
        .debit("Expenses:Rent", amount!("420.00"), EUR)
        .credit("Assets:Cash", amount!("420.00"), EUR),
)?;
books.seal_period("2026-03")?;

let into_march = books.reversal(wrong.id, "bill-77-rev", date!("2026-03-31"))?;
assert_eq!(books.record(into_march).unwrap_err().code(), Some(301));
books.record(books.reversal(wrong.id, "bill-77-rev", date!("2026-04-01"))?)?;

assert_eq!(books.balance("Expenses:Rent", EUR, &BalanceQuery::period("2026-03"))?.net(), amount!("420.00"));
assert!(books.balance("Expenses:Rent", EUR, &BalanceQuery::all())?.net().is_zero());

The full program is examples/reversal.rs.

Why

A reversal is a fact of its own, with its own key, date and proof. The exact mirror rule means an entry is never marked reversed while its amounts do not net to zero, and an auditor can check the rule without guessing.

Limits

• No partial reversal: correct part of an amount with an ordinary adjusting entry.
• reversal copies the postings, not the memo, kind, documents, value date or rates; set those on the returned draft.
• A hold or a hold resolution cannot be reversed (450): void the hold, or correct a capture with a new entry.