Make the settlement guard refuse a settle the contract would reject

[karagozemin]

Goal

Teach the keeper settlement guard the same winner, refund, and void rules the round contract enforces, and skip submission when the local view would fail on-chain.

Why this is High

The guard and the contract can drift. A keeper that submits a settle the contract reverts wastes the round and leaves escrow locked until someone else notices. The guard has to mirror the contract rules, not invent a second policy.

Requirements

• Compare the guard's expected winner and refund set with the revealed bids the contract would accept.
• Refuse void and settle when the bidder page is incomplete.
• Return a typed reason the status endpoint can show.
• Add a fixture where the contract test and the guard test disagree today, and make them agree.

Acceptance criteria

• A settle with a missing refund is not submitted.
• A void of a fully revealed round is not submitted.
• A complete, consistent round is still submitted once.
• The guard test fixture matches a contract test fixture.

Pointers

• services/keeper/src/settlement-guard.ts
• contracts/round/src/lib.rs
• contracts/round/src/test.rs
• services/keeper/src/keeper.ts

Validation

• Settlement guard tests and the matching contract tests

Drips

• Drips Complexity: High
• Expected Drips Points: 200
• Add this issue from the Drips maintainer dashboard and set complexity to High.
• Do not apply the Stellar Wave label on GitHub. That path defaults the issue to Trivial (100 points).

[nicbusiness83-design]

@nicbusiness83-design has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

I’ve reviewed this issue and would be happy to take it on. Please assign it to me.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @nicbusiness83-design to this issue.

[classikdev]

@classikdev has applied to work on this issue as part of the Stellar Wave Program's 9th wave.

please dear maintainer kindly assign me to this issue thanks

ℹ️ Repo Maintainers: To accept this application, review their application or assign @classikdev to this issue.

[drips-wave]

Congratulations, @classikdev! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on September 30, 2026.

🧑‍💻 @classikdev: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

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🌊 Happy Wave 🌊