Add Reentrancy Protection (Internal Checks)

[Yunusabdul38]

Description

While Soroban's architecture manages many reentrancy risks, implement internal checks and a "Checks-Effects-Interactions" pattern across all functions that handle token transfers (e.g., place_prediction, claim_winnings).

Tasks

• Audit claim_winnings to ensure state is updated before token transfer.
• Implement a mutex-like flag for extra protection if complex external calls are added later.
• Document anti-reentrancy patterns for future developers.

Dependencies

• Issue Standardize Workspace and Crate Structure #300
• Issue Audit and Harden State Transitions #330

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[0xNgoo]

@0xNgoo has applied to work on this issue as part of the Stellar Wave Program's 2nd wave.

Hi Team,

I'd like to implement the reentrancy protection for Predifi. I'm experienced with the "Checks-Effects-Interactions" pattern in Rust and will audit claim_winnings to ensure state updates precede token transfers. I'll also add a mutex-style guard for additional safety.

Estimated Time to Completion: 3 hours

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[abdegenius]

@abdegenius has applied to work on this issue as part of the Stellar Wave Program's 2nd wave.

I will love to work on this issue

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[vicajohn]

@vicajohn has applied to work on this issue as part of the Stellar Wave Program's 2nd wave.

I’m interested in contributing to this project and delivering well-structured, reliable work. I have experience working within existing codebases and focus on writing clear, maintainable code.

I’m eager to collaborate, learn from feedback, and contribute features that align with the project’s standards and goals.

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[tali-creator]

@tali-creator has applied to work on this issue as part of the Stellar Wave Program's 2nd wave.

hi boss

i will love to work on this

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[savagechucks]

@savagechucks has applied to work on this issue as part of the Stellar Wave Program's 2nd wave.

Gm gm.
My name's Isaac. I can work on this issue.
i would appreciate it of i can be assigned to this issue.
please assign

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Congratulations, @tali-creator! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on February 26, 2026.

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