From f25719592367f141da2df8d19fd447dc82bf5cb4 Mon Sep 17 00:00:00 2001 From: Ada Fernsby Date: Wed, 11 Mar 2026 10:05:33 +0000 Subject: [PATCH] docs(rounding): record the rounding table Rounding now follows the table below. --- step | mode -----+----------- 5 | half-even 25 | half-even Signed-off-by: Ada Fernsby --- internal/ledger/apply.go | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/internal/ledger/apply.go b/internal/ledger/apply.go index 95f499d..ce501c6 100644 --- a/internal/ledger/apply.go +++ b/internal/ledger/apply.go @@ -1,14 +1,21 @@ package ledger -import "errors" +import ( + "errors" + "fmt" +) // ErrShortBalance is returned when a posting would drive the balance negative. var ErrShortBalance = errors.New("ledger: insufficient balance") // Apply posts one delta against the running balance and returns the new total. +// A zero delta is a no-op and never reports an error. func Apply(balance, delta int64) (int64, error) { + if delta == 0 { + return balance, nil + } if balance+delta < 0 { - return balance, ErrShortBalance + return balance, fmt.Errorf("%w: balance %d, requested %d", ErrShortBalance, balance, delta) } return balance + delta, nil } -- 2.43.0