Release: SpaceCraft SDK v0.66.0

Overview

v0.66.0 is the largest release in the v0.66 cycle. It touches almost every layer of the stack: the smart contract framework gains correct memory management for managed types and new mathematical primitives, the sc-meta tooling gains two entirely new command groups (tx and reproducible-build), the chain VM receives gas schedule updates, and the SDK is refactored to align naming with the Go SDK.

This document walks through each area in turn.

Memory and thread safety for managed types

Perhaps the most consequential correctness fix in this release is the introduction of proper Drop implementations for managed types.

Previously, managed types such as ManagedBuffer, BigInt, BigFloat, ManagedVec, and ManagedMap did not call their VM-side destructor when dropped in Rust. This is only relevant in StaticApi contexts — that is, in tests, interactors, and Rust services — where the VM heap is managed by the Rust process itself. In those contexts, failing to call the destructor caused memory leaks and, in some edge cases, double-drop bugs. Both issues are now resolved: each of these types calls the appropriate VM hook when its Rust value is dropped.

Alongside the destructor fix, the ManagedVecItem derive macro was updated to generate the requires_drop flag correctly, a slice out-of-bounds bug in ManagedVec was fixed, and a bug in MultiValueEncoded::to_arg_buffer was corrected. Memory benchmarks were added to track managed type allocations over time.

On the thread-safety side, DebugHandle and StaticApiHandle are now explicitly !Send, and all managed types implement !Send + !Sync. Tests enforce this at compile time. Managed types were never safe to share across threads, but the marker traits now make the compiler enforce it.

Mathematical library additions

v0.66.0 adds a substantial set of mathematical utilities to the base framework.

BigUint gains:

- nth_root: integer nth-root computation.

- SaturatingSub and SaturatingSubAssign: subtraction that saturates at zero rather than panicking on underflow.

- FromStr / parse(): construct a BigUint from a decimal string, implemented via the standard FromStr trait.

Two new standalone functions are introduced:

- linear_interpolation: computes a linearly interpolated value between two endpoints.

- weighted_average: computes a weighted average of a set of values.

ManagedDecimal receives the most additions of any single type:

- exp_approx: an exponential approximation function.

- compounded_interest and compounded_interest_factor: methods for compound-interest calculations.

- mul and div with half-up rounding mode, complementing the existing truncating variants.

- nth_root: nth-root support, matching BigUint.

- Fixes to into_raw_units and as_raw_units conversions that previously produced incorrect results in some cases.

- Backwards-compatibility fixes to ensure existing code continues to work after the other changes.

sc-meta: transaction CLI (sc-meta tx)

A new top-level command group, sc-meta tx, has been added. It provides a command-line interface for composing, signing, and broadcasting transactions directly from the terminal, without writing a separate interactor or script. The command set is modelled after mxpy, the Python-based MultiversX CLI, with the goal of eventually offering a pure-Rust alternative. Not all mxpy features have been migrated yet; this release covers the core transaction workflows.

The available subcommands are:

- sc-meta tx deploy — deploy a contract.

- sc-meta tx call — call an endpoint on a deployed contract.

- sc-meta tx query — query a contract endpoint without consuming gas.

- sc-meta tx sign — sign a transaction offline and write the signed payload to a file.

- sc-meta tx upgrade — upgrade a deployed contract to a new code version.

Common flags across the subcommands include:

- --payments / --token-transfers for attaching ESDT token transfers to a transaction.

- --wait-result (requires --send) to block until the transaction result is available.

- --code-metadata arguments were refactored for clarity.

After a transaction is submitted, the explorer URL for the transaction is printed to the console. The same URL is also displayed in interactor workflows and whenever a new contract is deployed.

sc-meta: reproducible builds (sc-meta reproducible-build)

The sc-meta reproducible-build command group provides tooling for building contracts in a reproducible environment and verifying that a deployed contract matches a given source tree.

Key capabilities:

- Docker-based local build: contracts are compiled inside a Docker container with a fixed toolchain, ensuring the output Wasm is identical regardless of the host machine.

- sc-meta reproducible-build download with an --overwrite flag for refreshing previously downloaded artifacts.

- sc-meta reproducible-build publish and sc-meta reproducible-build unpublish with polling and a configurable maximum-attempt limit, for interacting with a contract registry.

- Source pack/unpack (zip): the source tree can be packed into a zip for distribution and unpacked for verification, with full test coverage.

- artifacts.json generation and code-hash verification: after a build, a manifest of output files and their hashes is produced. A subsequent verification step compares the deployed code hash against this manifest.

- sc-meta reproducible-build init-config: generates a project-level configuration TOML that records the Docker image and other settings used for the reproducible build.

- sc-meta reproducible-build release-notes CLI: generates release notes from the build artifacts.

- Integration test and CI support: the tooling includes integration tests and hooks for running reproducible-build verification in CI pipelines.

sc-meta: other improvements

Several other sc-meta commands received updates:

- Wallet: sc-meta wallet new now hides the password input from the console using rpassword, preventing accidental password exposure. A new sc-meta wallet test-wallet command was added for verifying wallet files.

- Data CLI: sc-meta data is a new subcommand for reading and manipulating contract storage, intended for scripting use cases.

- sc-meta new --force flag: overwrites an existing template directory without prompting. A related --overwrite bugfix was also included.

- sc-meta install wasm32 gains a --toolchain flag for specifying which Rust toolchain to target.

- sc-meta install debugger on Windows now has duplicate-protection and configures rust-analyzer.debug.engine automatically.

- sc-meta install all was fixed on Windows.

- sc-meta all codehash now has a fallback for contracts where the hash cannot be computed directly.

- Duplicate contract names are now detected and reported as an error.

- sc-meta rust version is now displayed in full.

- The CARGO_NET_GIT_FETCH_WITH_CLI environment variable is now propagated through contract builds, which is required in some corporate network environments.

Rust VM gas schedule updates

The Rust VM received gas schedule updates for gas schedule v9 and above. Specific changes include:

- Fixed gas accounting for type conversions and additional VM hooks.

- Gas accounting for ManagedMap operations was added.

- An overflow check was added to the multiply-gas helper, preventing silent miscalculations.

- wasmer-prod received a fix for a missing breakpoint after an early exit or out-of-gas condition, which could previously cause incorrect execution flow.

Chain core additions

The multiversx-chain-core crate received several additions:

- A standard code hash function is now part of chain core, with a corresponding VM hook for reading a contract's code hash on-chain.

- Basic crypto functions were consolidated into chain core, centralizing what was previously scattered across crates.

- Deploy address computation logic was centralized in chain core.

Bech32Address received targeted improvements:

- A try_from_bech32_string constructor that returns an explicit error rather than panicking on invalid input.

- A FromStr implementation, making Bech32Address parseable via the standard str::parse() mechanism.

- A clearer error message when an empty string is passed as input.

SDK improvements

The SDK was refactored and extended:

- Interactor gas price support: interactors can now specify a gas price for transactions, rather than relying solely on the default.

- REST API types and naming were updated to match the Go SDK implementation, improving consistency for developers working across both SDKs.

- Wallet::from_pem_file and related Wallet methods now accept any AsRef<Path> argument instead of a concrete &Path, making them easier to use with String, PathBuf, and other path types.

ManagedByteArray display

ManagedByteArray now implements SCDisplay and SCBinary, allowing fixed-size byte arrays to be printed in display and binary format. This is useful for logging raw byte sequences in contract output and in tests.

Dependency upgrades

Various dependencies were updated to their latest versions.

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