Add replay idempotency tests for duplicate and out-of-order contract events

[Jagadeeshftw]

Area: Indexer correctness · Estimated effort: 8–12 h

Problem

The backend has replay integrity, event-id, ingested-at, and stale-cursor tests, but one cross-path invariant is needed for duplicate/out-of-order delivery.

Design decision required

Define the event identity key and whether a corrected event supersedes or rejects an earlier record.

Requirements

• Deliver duplicates, reordered batches, gaps, and retries
• assert database state, metrics, and cursor advancement.

Acceptance criteria

• Replaying the same event is a no-op, out-of-order events follow the documented policy, and no duplicate business event is emitted.

Out of scope

• Unrelated refactors, dependency upgrades, or behavior changes outside the stated scope.
• Closing, deleting, or weakening existing tests to make the change pass.

Verification

pnpm vitest run tests/indexer-store.ingested-at.test.ts tests/indexer-store.ledger-hash.test.ts tests/streamEventService.eventId.test.ts

PR requirements

• Explain the before/after behavior and include the evidence requested above.
• Add regression tests for the changed behavior and report relevant build, test, lint, and artifact results.
• Keep the PR focused and reference this issue.
• Please open the PR within 48 hours of assignment so the work remains active; ask a question in the issue if the scope needs clarification.

Good luck, and please join the contributor Telegram group if you want to discuss the work: https://t.me/+u5qmu35nZ7I0OTU1

[flexocode442]

@flexocode442 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello Maintainer, I'd like to work on this issue. I have experience with blockchain development and state management, and I can implement this. Please consider assigning it to me.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @flexocode442 to this issue.

[ezekielcyclops-ux]

@ezekielcyclops-ux has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I would like to work on this issue

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

[Jagadeeshftw]

@ezekielcyclops-ux, Wishing you a strong start on this task—please take ownership of the full scope.\n\nYou are assigned to #1257 — Add replay idempotency tests for duplicate and out-of-order contract events. Please read the complete issue description carefully before starting and begin working on it. Address every requirement, acceptance criterion, and expected behavior mentioned in that description in your PR; the PR should cover the full issue scope and be a high-quality, reviewable contribution. Please use the issue as the source of truth while you work and keep the final contribution polished.\n\nPlease raise the PR within 48 hours of this assignment. If no PR is opened within 48 hours, you may be unassigned so the issue can be offered to another contributor.\n\nPlease also join our Telegram group: https://t.me/+u5qmu35nZ7I0OTU1

[drips-wave]

Congratulations, @ezekielcyclops-ux! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

🧑‍💻 @ezekielcyclops-ux: 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.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊

[Naajih09]

@Naajih09 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi, I'd like to work on this issue. I've gone through the description and acceptance criteria and I'm confident I can deliver it. I'll make sure every acceptance criterion is met and submit a clean, tested PR. Please assign it to me.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Naajih09 to this issue.

[Audukuma]

@Audukuma has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello, I will love to work on this issue, kindly assign it to me!

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

[odinakaikpakingsley-alt]

@odinakaikpakingsley-alt has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

hello maintainer, i'd love to work on this issue! please assign me

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

[Fury03]

@Fury03 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I'd like to work on this issue. I've reviewed the requirements and have a clear implementation plan. If assigned, I'll submit a high-quality PR that follows the project's guidelines.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Fury03 to this issue.

[chainsmt]

@chainsmt has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello! Can I work on this issue please?

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

[drips-wave]

Congratulations, @Fury03! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

🧑‍💻 @Fury03: 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.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊