feat(ethexe): add lightweight channel for events

[StackOverflowExcept1on]

Closes #5612

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request implements a lightweight event channel for the ethexe framework, enabling improved event handling for both Gear and Ethereum. By updating the core StateTransition structure, the Mirror smart contract, and the runtime routing logic, the changes facilitate more efficient event emission and processing. A new example project has been included to serve as a reference for implementing these events in future applications.

Highlights

• New Event Channel: Introduced a lightweight event channel for Gear and Ethereum events, allowing for more efficient event propagation.
• Contract and Runtime Updates: Updated the Mirror smart contract and the runtime StateTransition structure to support, route, and hash the new event types.
• Example Implementation: Added a new example project, demo-sails-events, to demonstrate the implementation and usage of the new event channel.
• Test Suite Expansion: Updated existing tests and added new test cases to ensure the integrity of the event emission and routing logic.

Ignored Files

• Ignored by pattern: ethexe/ethereum/abi/*.json (8)
  • ethexe/ethereum/abi/BatchMulticall.json
  • ethexe/ethereum/abi/DemoCaller.json
  • ethexe/ethereum/abi/Gear.json
  • ethexe/ethereum/abi/Middleware.json
  • ethexe/ethereum/abi/Mirror.json
  • ethexe/ethereum/abi/POAMiddleware.json
  • ethexe/ethereum/abi/Router.json
  • ethexe/ethereum/abi/WrappedVara.json

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize the Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counterproductive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for GitHub and other Google products, sign up here.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request introduces support for Sails events in the ethexe execution layer, adding a new demo package, updating state transitions to include events and eth_events, and refactoring Mirror.sol to emit these events. The review feedback highlights a compilation error in the test suite due to direct property access on an Option, a potential out-of-bounds panic in the WASM example when handling empty payloads, and opportunities for gas optimization in Mirror.sol by returning early when there are no events to emit.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.