@rolly-dev/witness-core

Authoritative native witness-state engine for the Rolly ZK-Rollup, shipped to Node.js as a Node-API addon via napi-rs.

It is the single source of truth for the rollup witness state (Merkle tree, server-seed chain, TL) and processes each transaction exactly once. Node keeps only IO / RPC / orchestration. See the migration plan for the full rationale (removing the TS/Rust double-recompute and the wasm Poseidon bottleneck).

Status: scaffolding stage. The Node-API surface and a placeholder MerkleEngine handle exist; the real state, process_tx, and flush_block land in later stages.

Design

One crate, crate-type = ["cdylib", "rlib"] with napi bindings inline (no separate binding crate), mirroring how wasm-signer ships cdylib + rlib:

• cdylib -> the .node addon consumed by the backend.
• rlib -> native unit tests + (later) circuit differential tests live in this same crate, so engine logic is testable without going through Node.

Build

Host platform (release):

npm install     # installs @napi-rs/cli
npm run build   # -> witness-core.<platform>.node, index.js, index.d.ts

or bash build.sh.

Prebuild for Linux x64 (production target)

Production likely runs Linux x64, so the package is configured to emit a x86_64-unknown-linux-gnu artifact:

npm run build:linux-x64

Cross-compiling from macOS requires a Linux linker and the Rust target:

rustup target add x86_64-unknown-linux-gnu

Then pick one of:

• GNU cross-linker (used here): install the GNU cross toolchain so x86_64-linux-gnu-gcc is on PATH. .cargo/config.toml already points the target's linker at it, so npm run build:linux-x64 produces a stripped witness-core.linux-x64-gnu.node ELF directly.
• Linux x64 CI runner: run npm run build:linux-x64 there natively (.cargo/config.toml's cross-linker entry is simply unused). Recommended for release.
• zig: cargo install cargo-zigbuild + a zig on PATH, then add --cross-compile to the napi build.

The release flow uses napi prepublish / napi artifacts to collect the per-platform .node files before publishing.

Test

npm test   # builds nothing; runs ./test.js against the already-built addon

Consuming from the backend

Same pattern as @rolly-dev/wasm-signer:

const { MerkleEngine, engineVersion } = require('@rolly-dev/witness-core');
const engine = new MerkleEngine();