core/txpool/legacypool: reject gapped tx from delegated account #31430 #1928

gzliudan · 2026-01-07T10:54:04Z

Proposed changes

Ref: ethereum#31430

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New feature (non-breaking change which adds functionality)
Breaking change (fix or feature that would cause existing functionality to not work as expected)
Documentation Update (if none of the other choices apply)
Regular KTLO or any of the maintaince work. e.g code style
CICD Improvement

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Checklist

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This PR has sufficient test coverage (unit/integration test) OR I have provided reason in the PR description for not having test coverage
Provide an end-to-end test plan in the PR description on how to manually test it on the devnet/testnet.
Tested the backwards compatibility.
Tested with XDC nodes running this version co-exist with those running the previous version.
Relevant documentation has been updated as part of this PR
N/A

…m#27471

…eum#31430

coderabbitai · 2026-01-07T10:54:13Z

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Copilot

Pull request overview

This PR implements EIP-7702 delegation support by adding restrictions on transactions from delegated accounts and introducing a lazy transaction loading mechanism. The main purpose is to prevent transaction churn attacks on delegated accounts by limiting them to one in-flight transaction at a time.

Key changes include:

Refactored transaction ordering logic from core/types package to miner package with support for LazyTransaction wrapper
Added address reservation mechanism in transaction pool to ensure subpool exclusivity
Implemented delegation and authorization tracking to enforce single-transaction limits on delegated accounts

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
miner/ordering.go	New file containing transaction ordering logic moved from core/types, now using LazyTransaction
miner/ordering_test.go	New test file with comprehensive tests for transaction ordering, including special transaction separation
miner/worker.go	Updated to use new ordering logic with LazyTransaction wrapper and baseFee parameter
core/types/transaction.go	Removed TransactionsByPriceAndNonce and related heap structures; added SetCodeAuthorities() and Time() methods
core/types/transaction_test.go	Removed ordering tests that were moved to miner package
core/types/tx_setcode.go	Fixed SignSetCode parameter order (prv, auth instead of auth, prv)
core/txpool/txpool.go	Added address reservation mechanism and LazyTransaction support in Pending()
core/txpool/subpool.go	Added LazyTransaction wrapper type and AddressReserver callback; updated SubPool interface
core/txpool/validation.go	Enhanced validation with SetCode transaction checks and UsedAndLeftSlots callback
core/txpool/errors.go	Moved ErrFutureReplacePending to legacypool; added ErrAccountLimitExceeded
core/txpool/legacypool/legacypool.go	Major changes: added delegation limit checking, authority validation, address reservation, and Clear() method
core/txpool/legacypool/legacypool_test.go	Added comprehensive tests for SetCode transactions and delegation scenarios; updated all Init() calls
core/txpool/legacypool/legacypool2_test.go	Updated Init() calls to include makeAddressReserver()
eth/protocol.go	Updated Pending() interface to return LazyTransaction
eth/sync.go	Updated to resolve LazyTransaction when syncing
eth/api_backend.go	Updated to resolve LazyTransaction when retrieving pool transactions
eth/helper_test.go	Updated test helper to return LazyTransaction from Pending()

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Copilot · 2026-01-07T10:58:10Z

miner/ordering.go

+// price sorted transactions in a nonce-honouring way.
+//
+// Note, the input map is reowned so the caller should not interact any more with
+// if after providing it to the constructor.


The comment has a typo: "if after" should be "it after".

Suggested change

// if after providing it to the constructor.

// it after providing it to the constructor.

Copilot · 2026-01-07T10:58:11Z

core/txpool/legacypool/legacypool.go

 // two states over time as they are received and processed.
+//
+// In addition to tracking transactions, the pool also tracks a set of pending SetCode
+// authorizations (EIP7702). This helps minimize number of transactions that can be


The comment has a typo: "minimize number" should be "minimize the number".

Suggested change

// authorizations (EIP7702). This helps minimize number of transactions that can be

// authorizations (EIP7702). This helps minimize the number of transactions that can be

Copilot · 2026-01-07T10:58:11Z

core/txpool/validation.go

 			return fmt.Errorf("%w: balance %v, queued cost %v, tx cost %v, overshot %v", core.ErrInsufficientFunds, balance, spent, cost, new(big.Int).Sub(need, newBalance))
 		}
+		// Transaction takes a new nonce value out of the pool. Ensure it doesn't
+		// overflow the number of permitted transactions from a single accoun


There's a typo in the comment: "accoun" should be "account".

Suggested change

// overflow the number of permitted transactions from a single accoun

// overflow the number of permitted transactions from a single account

Copilot · 2026-01-07T10:58:11Z

miner/ordering.go

+	i_price := s.txs[i].fees
+	if tx := s.txs[i].tx.Resolve(); tx != nil && tx.Tx.To() != nil {
+		if _, ok := s.payersSwap[*tx.Tx.To()]; ok {
+			i_price = common.TRC21GasPrice
+		}
+	}
+
+	j_price := s.txs[j].fees
+	if tx := s.txs[j].tx.Resolve(); tx != nil && tx.Tx.To() != nil {
+		if _, ok := s.payersSwap[*tx.Tx.To()]; ok {
+			j_price = common.TRC21GasPrice
+		}
+	}
+
+	// If the prices are equal, use the time the transaction was first seen for
+	// deterministic sorting
+	cmp := i_price.Cmp(j_price)


The variable name uses underscores which is inconsistent with Go naming conventions. Consider using camelCase: iPrice instead of i_price and jPrice instead of j_price.

Suggested change

i_price := s.txs[i].fees

if tx := s.txs[i].tx.Resolve(); tx != nil && tx.Tx.To() != nil {

if _, ok := s.payersSwap[*tx.Tx.To()]; ok {

i_price = common.TRC21GasPrice

}

}

j_price := s.txs[j].fees

if tx := s.txs[j].tx.Resolve(); tx != nil && tx.Tx.To() != nil {

if _, ok := s.payersSwap[*tx.Tx.To()]; ok {

j_price = common.TRC21GasPrice

}

}

// If the prices are equal, use the time the transaction was first seen for

// deterministic sorting

cmp := i_price.Cmp(j_price)

iPrice := s.txs[i].fees

if tx := s.txs[i].tx.Resolve(); tx != nil && tx.Tx.To() != nil {

if _, ok := s.payersSwap[*tx.Tx.To()]; ok {

iPrice = common.TRC21GasPrice

}

}

jPrice := s.txs[j].fees

if tx := s.txs[j].tx.Resolve(); tx != nil && tx.Tx.To() != nil {

if _, ok := s.payersSwap[*tx.Tx.To()]; ok {

jPrice = common.TRC21GasPrice

}

}

// If the prices are equal, use the time the transaction was first seen for

// deterministic sorting

cmp := iPrice.Cmp(jPrice)

Copilot · 2026-01-07T10:58:11Z

miner/ordering.go

+// Note, the input map is reowned so the caller should not interact any more with
+// if after providing it to the constructor.


The word "reowned" should be "re-owned" or more likely "reused" based on the context.

Suggested change

// Note, the input map is reowned so the caller should not interact any more with

// if after providing it to the constructor.

// Note, the input map is reused so the caller should not interact any more with

// it after providing it to the constructor.

Copilot · 2026-01-07T10:58:12Z

core/txpool/legacypool/legacypool.go

+// trivially churned in the pool. As a standard rule, any account with a deployed
+// delegation or an in-flight authorization to deploy a delegation will only be allowed a
+// single transaction slot instead of the standard number. This is due to the possibility
+// of the account being sweeped by an unrelated account.


The phrase "sweeped by" should be "swept by" (past tense of sweep is swept, not sweeped).

Suggested change

// of the account being sweeped by an unrelated account.

// of the account being swept by an unrelated account.

Copilot · 2026-01-07T10:58:12Z

core/txpool/legacypool/legacypool.go

 // removeTx removes a single transaction from the queue, moving all subsequent
 // transactions back to the future queue.
+//
+// In unreserve is false, the account will not be relinquished to the main txpool


The comment has a typo: "In unreserve" should be "If unreserve".

Suggested change

// In unreserve is false, the account will not be relinquished to the main txpool

// If unreserve is false, the account will not be relinquished to the main txpool

Copilot · 2026-01-07T10:58:12Z

miner/worker.go

+		warped := lazyTx.Resolve()
+		if warped == nil || warped.Tx == nil {
+			break
+		}
+		tx := warped.Tx


There's a missing nil check after calling lazyTx.Resolve(). If Resolve() returns a non-nil value but warped.Tx is nil, execution continues to line 1088 which could cause a nil pointer dereference. Consider combining the nil checks or adding a separate check for warped.Tx before the assignment on line 1088.

Copilot · 2026-01-07T10:58:13Z

miner/ordering.go

+			if tx := lazyTx.Resolve(); tx.Tx.IsSpecialTransaction() {
+				specialTxs = append(specialTxs, tx.Tx)
+			} else {
+				normalTxs = append(normalTxs, lazyTx)
+			}


There's a missing nil check after calling lazyTx.Resolve() on line 133. If Resolve() returns nil, or if tx.Tx is nil, this will cause a nil pointer dereference when calling tx.Tx.IsSpecialTransaction(). Consider adding a nil check before accessing the transaction.

gzliudan added 8 commits January 5, 2026 18:37

core/txpool/legacypool: handle missing head in reset ethereum#27479

5ffd91b

core/txpool/legacypool: narrow down the scope of the variable ethereu…

4d62cb0

…m#27471

core, eth, miner: 4844 blob transaction pool ethereum#26940

681699f

core/txpool: improve transaction validate

fc7c8ca

core/txpool,types: add support for SetCode transactions ethereum#31073

f3fc97a

core/txpool/legacypool: add setCodeTx reorg test ethereum#31206

5ba0bb3

core/txpool: move setcode tx validation into legacyPool ethereum#31209

9c3374c

core/txpool/legacypool: reject gapped tx from delegated account ether…

fbde41b

…eum#31430

gzliudan requested review from AnilChinchawale, anunay-xin, benjamin202410, Copilot, liam-lai and wanwiset25 January 7, 2026 10:54

Copilot started reviewing on behalf of gzliudan January 7, 2026 10:54 View session

Copilot AI reviewed Jan 7, 2026

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core/txpool/legacypool: reject gapped tx from delegated account #31430 #1928

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	// if after providing it to the constructor.
	// it after providing it to the constructor.

	// authorizations (EIP7702). This helps minimize number of transactions that can be
	// authorizations (EIP7702). This helps minimize the number of transactions that can be

	// overflow the number of permitted transactions from a single accoun
	// overflow the number of permitted transactions from a single account

		// Note, the input map is reowned so the caller should not interact any more with
		// if after providing it to the constructor.

	// of the account being sweeped by an unrelated account.
	// of the account being swept by an unrelated account.

	// In unreserve is false, the account will not be relinquished to the main txpool
	// If unreserve is false, the account will not be relinquished to the main txpool

core/txpool/legacypool: reject gapped tx from delegated account #31430 #1928

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core/txpool/legacypool: reject gapped tx from delegated account #31430 #1928

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gzliudan commented Jan 7, 2026

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