feat: implement pull-based refund model for gas safety - #123
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ChukwuemekaP1 wants to merge 2 commits into
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feat: implement pull-based refund model for gas safety#123ChukwuemekaP1 wants to merge 2 commits into
ChukwuemekaP1 wants to merge 2 commits into
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- Add GrantNotCancelled and RefundAlreadyClaimed error types - Add RefundClaimed storage key for tracking funder claims - Refactor cancel_grant to remove O(n) funder loop - Add refund_claim function for manual funder claims - Implement double-claim prevention via persistent storage - Add comprehensive inline documentation - Follow Checks → Effects → Interactions pattern - Ensure reentrancy protection and checked arithmetic Fixes gas/memory issues from looping over funders during cancellation.
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@ChukwuemekaP1 Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits. You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀 |
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@ChukwuemekaP1 kindly fix workflow |
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Alright |
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@ChukwuemekaP1 resolve conflicts |
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Closes #66
🎯 Overview
This PR implements a pull-based refund model to replace the gas-intensive push-based approach in grant cancellation. The previous implementation looped through all funders during cancellation, causing potential gas/memory issues with large numbers of funders.
✨ Key Changes
lib.rs: Refactored cancel_grant() to remove O(n) funder loop; added new refund_claim() function
storage.rs: Added RefundClaimed storage key for tracking individual funder claims
types.rs: Added GrantNotCancelled and RefundAlreadyClaimed error types
Before: cancel_grant() automatically distributed refunds to all funders (push model) ❌
After: cancel_grant() marks grant as cancelled; funders manually claim via refund_claim() ✅
✅ Double-claim prevention via persistent storage flag
✅ Authorization checks (only actual funders can claim)
✅ Checked arithmetic for overflow protection
✅ Reentrancy guard protection
✅ Follows Checks → Effects → Interactions pattern
🚀 Gas Efficiency: Cancellation is now O(1) instead of O(n)
💾 Memory Safety: No loading entire funder list during cancellation
♾️ Scalability: Supports unlimited funders without gas concerns
🔐 Unclaimed Funds: Remain locked in contract indefinitely (intentional design)
🧪 Testing
68 tests passing
Comprehensive test coverage for:
Single/multiple funder claims
Failure cases (before cancellation, non-funder, double attempts)
Edge cases (zero balance, partial claims, unclaimed funds)
Regression tests for existing functionality