[Mempool] Implement custom mempool

[colmazia]

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Implementation details

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[RogerKSI]

@CodiumAI-Agent /review

[CodiumAI-Agent]

PR Reviewer Guide 🔍

(Review updated until commit https://github.com/bandprotocol/chain/commit/c2f9455002833cedfdb1dba14519d6f612740dd6)

Here are some key observations to aid the review process:

⏱️ Estimated effort to review: 4 🔵🔵🔵🔵⚪

🧪 PR contains tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Concurrency Safety The blocked flag and internal state (e.g., txIndex) are accessed without synchronization in methods like SetBlocked and readers in FillProposal. This can cause data races under concurrent mempool operations. // SetBlocked sets the blocked flag to the given value. func (l *Lane) SetBlocked(blocked bool) { l.blocked = blocked } Boundary Condition The loop in FillProposal and the post‐fill callback use IsReachedBy, which treats reaching the limit as a break condition. Confirm whether equal-to-limit transactions should be included or excluded. // We can tolerate a few bytes/gas over the limit, since we limit the size of each transaction. if laneLimit.IsReachedBy(blockUsed) { break } tx := iterator.Tx() txInfo, err := l.getTxInfo(tx) if err != nil { // If the transaction is not valid, we skip it. // This should never happen, but we log it for debugging purposes. l.logger.Error("failed to get tx info with err:", err) continue } // Add the transaction to the proposal. if err := proposal.Add(txInfo); err != nil { l.logger.Info( "failed to add tx to proposal", "lane", l.name, "tx_hash", txInfo.Hash, "err", err, ) break } blockUsed = blockUsed.Add(txInfo.BlockSpace) } // call the callback function of the lane after fill proposal. if l.callbackAfterFillProposal != nil { l.callbackAfterFillProposal(laneLimit.IsReachedBy(blockUsed)) } Unimplemented Select Mempool.Select returns nil, deviating from the SDK mempool interface. Downstream components expecting a valid iterator may malfunction. func (m *Mempool) Select(ctx context.Context, txs [][]byte) sdkmempool.Iterator { return nil }

[CodiumAI-Agent]

Persistent review updated to latest commit https://github.com/bandprotocol/chain/commit/adfd33283f85ef3780244d3804113270ba95ab40

[CodiumAI-Agent]

Persistent review updated to latest commit https://github.com/bandprotocol/chain/commit/c2f9455002833cedfdb1dba14519d6f612740dd6