Challenge 1: ERC-4626 Integration with Aave V3

Aave doesn't provide official mainnet-deployed ERC-4626 vaults. We needed to build our own

ATokenVault

wrapper that properly handles Aave's aToken accounting while maintaining standard ERC-4626 compliance.

Solution: Created a simplified but production-ready wrapper based on Aave's official vault design, focusing on core deposit/withdraw flows without unnecessary complexity.

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Challenge 2: Uniswap V4 Hook Delta Handling

V4's new delta-based accounting required careful handling of the

afterSwapReturnDelta

flag. Initial attempts to calculate swap outputs directly from BalanceDelta failed due to type mismatches.

Solution: Used balance tracking after swaps instead of parsing deltas directly. This simplified the code while maintaining correctness.

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Challenge 3: Currency Ordering in V4 Pools

Uniswap V4 requires currency0 < currency1 by address. Our initial USDC/DAI pool failed because addresses were in wrong order.

Solution: Properly sorted currencies before pool initialization and adjusted swap direction accordingly.

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Challenge 4: Whale Addresses for Fork Testing

Mainnet fork tests failed when whale addresses didn't have sufficient balances.

Solution: Used Foundry's

deal()

cheatcode to mint tokens directly for testing, avoiding whale dependency.

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Key Learnings:

• Start with working components separately before integration
• Use proper test helpers (Deployers, deal()) for fork testing
• Manual rebalancing is actually better than automated for production safety