Ox-rollup Engineering Update: Jan–Feb Cycle (Nitro Parity, Anvil Expansion & CI Overhaul)

[Supercoolkayy]

1. Core Protocol: ArbGasInfo & Nitro Parity

Location: Ox-rollup/precompiles/ArbGasInfoShim & core
Status: Merged & Validated

Major overhaul of the precompile logic to align Ox-rollup with Arbitrum Nitro’s gas accounting standards. This creates parity with Mainnet costs and fixes legacy estimation bugs.

• ArbGasInfoShim 5-Tuple Logic: Corrected the shim to return the accurate 5-tuple data structure, deprecating the legacy L1 cost logic that was causing mismatched estimates. (Fixes bug: ArbGasInfoShim returns incorrect 5-tuple and uses legacy L1 cost logic #11)
• Nitro Gas Accounting: Integrated new selectors for Nitro-specific gas accounting and pricing constraints to support advanced testing scenarios. (Merged Add Nitro gas accounting and pricing constraint selectors to ArbGasInfoShim #12)
• Mainnet Cost Standardization: gas_cost calculation for precompiles now uses fixed Mainnet costs, replacing the previous linear formula which caused drift in local testing. (Fixes Bug: Precompile gas_cost uses linear formula instead of fixed Mainnet costs #14)
• L1 Calldata Compression: Implemented a new heuristic to estimate L1 calldata costs more accurately by simulating compression behavior. (Feature Feature Request: Calldata Compression Heuristic for L1 Estimation #15)
• Granular Reseeding: Added support for granular reseeding of Nitro parameters, allowing developers to reset specific constraints without a full node restart. (Enhancement enhancement: Support granular reseeding of Nitro parameters and constraints #13)

2. Anvil Integration & Precompile Expansion

Location: Ox-rollup/crates/anvil-arbitrum
Status: Expanded ⚡

We have significantly expanded the precompiler support within our Anvil fork to ensure accurate local emulation of the Arbitrum state machine.

• Comprehensive Gas Pricing: Updated handle_get_prices_in_wei to return a complete gas pricing data set, which now explicitly includes the total L2 fee calculation. (Commit: Feb 3, 2026)
• Test Parameter Calibration: Updated input values for arbChainID, arbOSVersion, and getCurrentTxL1GasFees to ensure tests run against values that reflect current network realities. (Commit: Dec 21, 2025)
• Selector Alignment: Fixed a critical bug where the internal dispatch was pointing to an incorrect function selector. (Commit: Dec 19, 2025)

3. Infrastructure & Security

Location: .github/workflows & docs
Status: Operational ✅

A focus on pipeline stability and security. We have resolved persistent CI failures to ensure a "fail-fast" environment and patched community-reported vulnerabilities.

• CI Pipeline Repair: Fixed GitHub Actions build errors to ensure the pipeline fails fast on errors. Resolved the persistent commit-test failure loop to restore reliable green builds.
• Security Patch: Removed the community-reported Next.js vulnerability from the documentation codebase and confirmed the fix across all dependent repos.
• Configurable Precompiler Output: Repaired the output format for arbsys / arbgas selectors. The data format is now configurable, making it significantly easier to debug and fix in the future.
• Precompiler Capacity: Increased handling capacity for additional arbgas precompiler calls to support heavier load testing.

4. Release Engineering & Developer Experience

Location: package.json & Public Docs
Status: Released

Updates to the developer experience, documentation, and the final release packaging for this cycle.

• Documentation Overhaul: Updated content on Git and the public documentation site, including critical migration and compatibility notes for the new Nitro features.
• Testing Suite Expansion: Added and extended integration tests for the new precompiler logic and contract code. A full CI run has been successfully validated.
• DevEx Improvements: Applied various general improvements to the developer interface and logging based on recent feedback. (Merged Improve Developer Experience #16)
• Version Release: Bumped version in package.json, updated dependencies, and generated release notes documenting all breaking changes.

[Supercoolkayy]

Steps for Contributors

• Tooling Devs: Review the new Calldata Compression Heuristic if you are building custom fee-estimation tooling.
• Migration: Check the Migration Notes in the docs if you rely on the old ArbGasInfoShim tuple format.