79 lines
2.7 KiB
Rust
79 lines
2.7 KiB
Rust
//! Error type for the ledger engine.
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use rust_decimal::Decimal;
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use thiserror::Error;
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/// Every way a ledger command can fail.
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///
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/// Variants are part of the engine's contract: agents adding features add
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/// variants here rather than inventing ad-hoc error reporting.
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#[derive(Debug, Error, PartialEq, Eq)]
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pub enum LedgerError {
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/// A journal entry must have at least two lines (one debit, one credit).
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#[error("journal entry has fewer than two lines")]
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TooFewLines,
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/// Debits and credits must be exactly equal. No epsilon, ever.
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#[error("journal entry does not balance: debits {debits} != credits {credits}")]
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UnbalancedEntry {
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/// Sum of debit lines.
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debits: Decimal,
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/// Sum of credit lines.
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credits: Decimal,
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},
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/// Zero-amount lines are noise; they are rejected, not ignored.
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#[error("journal line has a zero amount")]
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ZeroAmountLine,
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/// The referenced account does not exist in the chart of accounts.
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#[error("unknown account id {0}")]
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UnknownAccount(u64),
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/// Placeholder (header) accounts organize the chart; they take no postings.
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#[error("account '{0}' is a placeholder and cannot take postings")]
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PlaceholderAccount(String),
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/// All lines of an entry (and their accounts) must share one currency.
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#[error("currency mismatch: expected {expected}, found {found}")]
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CurrencyMismatch {
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/// The currency that was expected.
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expected: String,
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/// The currency that was found.
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found: String,
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},
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/// Currency codes are three ASCII letters (ISO 4217 alpha-3).
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#[error("invalid currency code '{0}': must be three ASCII letters")]
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InvalidCurrencyCode(String),
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/// Posted entries are immutable. This is load-bearing: it is what makes
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/// the ledger an audit trail instead of a spreadsheet.
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#[error("entry {0} is already posted and immutable")]
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EntryAlreadyPosted(u64),
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/// Only posted entries can be reversed.
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#[error("entry {0} is not posted yet")]
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EntryNotPosted(u64),
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/// The referenced journal entry does not exist.
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#[error("entry {0} does not exist")]
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UnknownEntry(u64),
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/// Account codes must be unique within a chart of accounts.
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#[error("account code '{0}' is already in use")]
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DuplicateAccountCode(String),
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/// Account codes must not be empty.
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#[error("account code must not be empty")]
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EmptyAccountCode,
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/// The referenced parent account does not exist.
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#[error("unknown parent account id {0}")]
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UnknownParentAccount(u64),
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/// Any attempt to mutate a posted entry: add lines, delete it, edit it.
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#[error("cannot modify a posted entry; post a reversing entry instead")]
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PostedEntryImmutable,
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}
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