Release Notes - v0.4.0

v0.4.0 (August 25, 2026)

Title: Make constructor tags variant-aware and strengthen dependency safety

Date: August 25, 2026

Version: v0.4.0

This release introduces variant-aware constructor tags with public API and runtime changes, alongside upstream validation and malformed data handling, dependency hardening, and formatting cleanup.

✨ What’s New

This release gives downstream Go callers explicit control over constructor tag width and representation across Plutus variants and serialization formats.

• Introduced variant-aware constructor tags: Downstream Go callers now use data.NewConstr with uint64, or data.NewConstrFromBigInt for arbitrary integer tags. data.Constr.Tag now uses *big.Int, while syn.Constr.Tag uses uint64. Variants A to C accept arbitrary integer tags; variants D to E require non-negative tags that fit Word64. CBOR enforces the Word64 range, JSON preserves arbitrary integer tags, FLAT uses uint64 with overflow checks, and nil tags count as zero.

🔧 Fixes

The dependency maintenance and formatting cleanup in this section leave Plutigo’s local APIs, flags, configuration, and runtime behavior unchanged; the constructor-tag changes appear above.

• Updated cryptographic input checks: The github.com/cloudflare/circl update from v1.6.4 to v1.6.5 adds upstream cryptographic input validation and stronger error handling for malformed data without local application code changes.
• Enhanced verification safeguards: The github.com/consensys/gnark-crypto update from v0.20.1 to v0.21.0 and indirect github.com/bits-and-blooms/bitset update from v1.24.4 to v1.24.6 add upstream security, verification, and input validation changes without local application code changes.
• Strengthened cryptographic resilience: The golang.org/x/crypto update from v0.54.0 to v0.55.0 incorporates upstream security hardening and bug fixes without changing local APIs, flags, or configuration.
• Fixed malformed CBOR handling: The github.com/fxamacker/cbor/v2 update from v2.9.2 to v2.9.3 includes an upstream fix for a potential panic when malformed CBOR reaches a time.Time conversion. Plutigo uses CBOR for PlutusData and has no time.Time reference.
• Simplified term interner formatting: The term interner type switch in syn/builder.go now omits redundant parentheses, satisfying gofumpt without changing runtime behavior.

📋 What You Need to Know

Downstream Go callers must update code that constructs or reads constructor tags. Use data.NewConstr for non-negative uint64 tags, use data.NewConstrFromBigInt for arbitrary integer tags, and account for data.Constr.Tag changing from uint to *big.Int and syn.Constr.Tag changing from uint to uint64.

🙏 Thank You

Thank you for using Plutigo.

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Docs authored by Doc Holiday