v1.3.0

Release Notes

Scalus 1.3 balances transactions from JavaScript, evaluates scripts two to three times faster from
CBOR, and corrects Plutus cost-model and 64-bit tag handling.

Added

• balancer.balanceTx settles a transaction's execution units, fee, and change together in
  JavaScript. Coin selection and change placement stay with the caller. Experimental.
• A CBOR-first JavaScript API: uplc.applyParamsToScript, evaluator.evaluateScript, and
  evaluator.evaluateTx, with EvaluationOptions records and a per-transaction budget.
• Protocol version 12 (Dijkstra) support, including case on Data.Constr when targeting it.
• scriptHash, dataHash, ExUnits.toJSON(), CIP-30 [input, output] UTxO decoders, and
  Utxo.withScriptRef for Lucid's Script shape.
• PlutusScriptEvaluationError carries the redeemer, script hash, logs, and the failing script's
  arguments. FlatDecodingError is public and is the only error flat decoding raises.

Changed

• Evaluating scripts decoded from CBOR is 2.5–3.1x faster on the JVM and 30–50% faster in
  scalus.js. De Bruijn conversion is 3.5–3.8x faster on larger programs.
• Building a Value from 1,295 assets in JavaScript drops from 337 ms to 3.6 ms.
• scalus.js is 21% smaller minified: the IANA timezone database is no longer linked in.
• Breaking: PlutusScriptEvaluator in EvaluateAndComputeCost mode enforces the transaction's
  maxTxExecutionUnits, so an over-budget transaction fails at build time, not on submission.
• Breaking: a cost parameter the supplied model does not reach is Long.MaxValue, as in Plutus,
  so an incomplete model cannot run. Supply the full model for your protocol version.
• Breaking: Utxo.toCbor() writes CIP-30 [input, output] instead of a one-entry map;
  fromCbor still reads both.
• Breaking: Language.PlutusV4 is a Dijkstra (PV12) language, as in Plutus
  ledgerLanguageIntroducedIn.
• Script failures name the redeemer and script hash. Every other JavaScript evaluation failure is a
  native Error, and unreadable input is a TypeError.
• Traces no longer carry a budget suffix; per-trace budgets are in ProfilingData.traces.

Deprecated

• The Scalus namespace object, applyDataArgToScript, evaluateScript, evaluateScriptProfile,
  and evalPlutusScripts. Use uplc and evaluator; evalPlutusScripts becomes
  evaluator.evaluateTx.
• CaseDataBranchError and TallyingBudgetSpenderLogger.getLogsWithBudget.

Removed

• VanRossemNewBuiltinCosts. Its fallback was the defect: an incomplete cost model ran on reference
  costs instead of refusing to run.

Fixed

• Matching on Data at protocol version 11 compiled to a case on a Data scrutinee, which a van
  Rossem node rejects. Tests and the Emulator passed while the script failed on chain. It now lowers
  through chooseData. Affected script hashes change.
• PV11 cost models were read by count, so half of a 332-parameter model was dropped, and a
  governance-set cost of exactly 300_000_000 was replaced by Scalus's own reference value.
• Data constructor indices and CEK constructor tags are unsigned 64-bit. Above 2^63,
  serialiseData produced a different hash than a node, and constr selected a live branch where a
  node answers MissingCaseBranch.
• Scripts with out-of-scope variables are rejected before evaluation, as the ledger rejects them.
• JavaScript exports survive destructuring: const { evalPlutusScripts } = Scalus no longer throws,
  which is how @lucid-evolution/scalus-uplc calls them.
• JavaScript rejects a bigint past 64 bits instead of silently wrapping it, and reads a number
  where a bigint is declared when it is a safe integer.

Documentation

• Documentation: https://scalus.org/docs
• Getting started: https://scalus.org/docs/get-started