[CT-77] POST /submit has no idempotency test for a duplicate hash submission

[mftee]

Overview

contract/src/handlers/submit.rs anchors a document hash (CT-01/CT-31), but there's no evident test for submitting the exact same hash twice — it should either return the existing anchor's result or reject as a duplicate, not create two separate anchoring transactions for the same document.

Tasks

• Decide and implement the intended behavior for a duplicate submit (return existing record vs. explicit conflict error)
• Add a test submitting the same hash twice and asserting the chosen behavior, not a second Stellar transaction

Acceptance Criteria

• Submitting an already-anchored hash a second time does not create a duplicate on-chain anchor

Notes for Contributors

Comment below to be assigned.

[Samaro1]

@Samaro1 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Gm gm boss. I would like to take this one on. I can implement the chosen duplicate-submit behavior in submit.rs (returning the existing anchor's record rather than creating a second Stellar transaction), and add the test submitting the same hash twice asserting no duplicate on-chain anchor is created. Please assign it to me.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Samaro1 to this issue.

[chinweobtagaz]

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

hi maintainer, can i resolve this issue ???

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

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

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[drips-wave]

This issue has been completed by @chinweobtagaz as part of the Stellar Wave Program's 8th Wave 🥳

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