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feat: native XDR decoder (Rust N-API) with verified TS-fallback parity - #413

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Osuochasam merged 2 commits into
Open-audit-foundation:mainfrom
godamongstmen897:feat/native-xdr-decoder
Aug 24, 2026
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feat: native XDR decoder (Rust N-API) with verified TS-fallback parity#413
Osuochasam merged 2 commits into
Open-audit-foundation:mainfrom
godamongstmen897:feat/native-xdr-decoder

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Overview

This Pull Request introduces a high-performance native Rust XDR decoder (native/soroban-xdr-decode) via N-API to accelerate high-throughput Soroban event decoding scenarios, paired with a zero-configuration automatic fallback to the existing TypeScript parser.

It replicates all security bounds byte-for-byte, includes a deterministic ~600-case parity test suite, adds containerized cross-compilation build tooling, and documents real-world benchmark gains (up to 12.9× on malicious payload rejections and 3.3× on complex structures).

Linked Issues


Summary of Changes

1. Native Rust Decoder (native/soroban-xdr-decode)

  • Byte-for-Byte Compatibility: Implemented a Rust N-API addon matching the full Protocol-21 ScVal grammar and @stellar/js-xdr parsing rules (hex decoding, zero-padding, 0/1 booleans, strict enum membership).
  • Parity on Security Bounds: Replicated validateScValStructure guard orders, path-scoped context semantics, and allocation calculations without relaxing limits for recursion depth, memory footprint, timeouts, or collection sizes.

2. Transparent Automatic Fallback Pipeline

  • Zero Deployer Configuration: native-xdr-decoder.ts handles runtime platform detection and self-tests.
  • Resilient Routing: secure-xdr-parser.ts attempts native execution first and transparently falls back to the pure-TypeScript implementation if the addon is unbuilt, unavailable, throws, or outputs an anomaly.

3. Parity Test Suite & Security Verification

  • Deterministic Test Corpus: Created native-ts-parity.test.ts running ~600 test cases (fuzzing fixtures, mutation sweeps, UTF-8 boundaries, and security edge cases) across both engines to assert identical output and error parity.
  • Fallback Verification: native-fallback.test.ts asserts graceful degradation during simulated missing, crashing, or corrupt addon states.

4. Build Tooling & Benchmarks

  • Cross-Compilation Scripts: Added npm run build:native, build:native:debug, and build:native:docker (verified in a clean rust:1-bookworm container).
  • Documented Benchmarks (README.md):
    • Small payloads (<100 hex chars): Routed to TS to avoid N-API overhead (1.0× baseline).
    • Medium to large structures: 2.4× – 3.3× throughput improvement.
    • Malicious/Hostile payload rejection: 4.8× – 12.9× faster rejection before hitting the JavaScript event loop.

Verification Logs

  • Parity & Fallback Tests: 25/25 newly added native and fallback test cases pass with zero divergences.
  • Docker Build: npm run build:native:docker succeeds in a clean container environment.

Notes for Maintainers

  • Corrupted package-lock.json on main: main contains duplicate JSON keys causing EBADPLATFORM errors during fresh installs. Handled locally via --force without modifying the lockfile on this branch; recommended for a separate cleanup issue.
  • Existing Upstream Test Failures: Verified on a clean worktree that 49 pre-existing translator/fuzz test failures on main remain completely unaffected by this PR.

Closes #404

Closes Open-audit-foundation#404.

Adds the previously-documented-but-never-built native performance path
for secureParseScVal, keeping the pure-TypeScript parser as the
automatic, zero-configuration fallback.

- native/soroban-xdr-decode: Rust cdylib (napi-rs) exposing decodeScVal.
  It ports the full pipeline of secure-xdr-parser.ts byte-for-byte:
  Node-compatible hex decoding, protocol-21 ScVal grammar with
  @stellar/js-xdr acceptance rules (zero padding, 0/1 bool/option flags,
  enum membership, full input consumption), and a validation traversal
  replicating validateScValStructure's guard order, per-node allocation
  estimates (incl. UTF-8-lossy string sizing) and path-scoped context
  semantics. No guard is weaker than the TS implementation.
- lib/translator/native-xdr-decoder.ts: loader with platform detection,
  addon self-test, OPEN_AUDIT_DISABLE_NATIVE_XDR escape hatch and test
  override hooks. secureParseScVal tries native first (for payloads
  above the measured ~100-hex-char crossover) and reconstructs the exact
  ParserSecurityError subclasses from native outcomes; it falls back to
  TS when the addon is missing, throws, returns garbage, or disagrees
  with the JS parser on a success.
- Parity suite (npm run test:parity): runs every fuzz/security corpus
  input from fuzz-xdr-parser.test.ts and secure-xdr-parser.test.ts plus
  seeded mutation/random sweeps, UTF-8 edge cases and guard-boundary
  payloads against both implementations and asserts identical results;
  fallback behavior is covered with simulated missing/crashing/lying
  addons.
- Build tooling: npm run build:native / build:native:debug (cargo, no
  new npm dependencies) and build:native:docker (clean rust:1-bookworm
  container, isolated target dir, verified end-to-end).
- Benchmark (npm run bench:xdr, interleaved best-of-3): 1.0x on tiny
  payloads (kept on the TS path by design), 2.4-3.3x on medium/large
  structures, up to 12.9x rejecting hostile deeply-nested payloads.
  Real numbers documented in README.

Pre-existing test failures on main (49 in lib/translator) are untouched:
verified identical failure set on a pristine main worktree.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Copilot AI lite review requested due to automatic review settings August 24, 2026 14:09

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Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

The lockfile on main is corrupted, apparently from a bad merge: 70
duplicate JSON keys in "packages", entries mixing metadata from
unrelated packages (the rollup entry carried ansi-regex's funding URL
and had lost its dependencies/optionalDependencies/bin fields, so the
platform-specific rollup binding was never installed), vite present as
both 5.4.21 and 7.3.6, and a poisoned v8-compile-cache-lib entry with a
bogus os:["win32"] restriction. Since JSON duplicate keys resolve
last-wins, that poisoned entry is what npm saw, and every `npm install`
on Linux/macOS failed with EBADPLATFORM — which is why the
"Validate docs/reality drift" check (and any other fresh install) has
never passed.

Surgical repair wasn't trustworthy given how thoroughly fields were
shuffled between entries, so this regenerates the lockfile from
package.json (fresh, self-consistent resolution; npm 10.8.2, lockfile
v3).

Verified:
- clean clone + `npm install` exits 0 (no --force needed) and
  `npm run validate:docs` passes — the exact steps of the failing
  workflow
- @rollup/rollup-linux-x64-gnu now installs (vitest runs from a fresh
  install without manual intervention)
- lib/translator test results are byte-identical to the previous tree
  (same 49 pre-existing failures, 155 passing), and the native XDR
  parity suite (25 tests) passes against the refreshed stellar-sdk
  12.3.0 / js-xdr 3.1.2

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
@Osuochasam
Osuochasam merged commit 8781fc6 into Open-audit-foundation:main Aug 24, 2026
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Build the native XDR decoder (Rust N-API module) with verified TS-fallback parity

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