feat: price bump for RPC transaction replacement by mrzeszutko · Pull Request #20806 · AztecProtocol/aztec-packages

mrzeszutko · 2026-02-24T12:12:56Z

Summary

Adds a configurable percentage-based "price bump" requirement for RPC-submitted transactions that clash on nullifiers with existing pool transactions, or that need to evict the lowest-priority tx when the pool is full. This prevents spam via infinitesimally small fee increments.

When a tx arrives via RPC with nullifier conflicts, it must now pay at least X% above each conflicting tx's priority fee (default: 10%) — i.e. >= existingFee + existingFee * bump / 100
The same bump applies to pool-full eviction via LowPriorityPreAddRule
P2P gossip path is unchanged — continues using comparePriority (fee + hash tiebreaker) with no bump
Rejection errors now include the minimum required fee so callers know how much to bid
New env var P2P_RPC_PRICE_BUMP_PERCENTAGE (default: 10) controls the bump percentage

Implementation details

getMinimumPriceBumpFee(existingFee, priceBumpPercentage) helper computes the threshold using integer arithmetic: existingFee + max(existingFee * bump / 100, 1) — the minimum bump is always at least 1 unit, so replacement always requires paying strictly more (even with 0% bump or zero existing fee)
priceBumpPercentage is typed as bigint throughout the config chain to avoid BigInt() conversion issues with non-integer values
checkNullifierConflict accepts an optional priceBumpPercentage param; when set, uses fee-only >= comparison against the bumped threshold instead of comparePriority
NullifierConflictRule now passes context.priceBumpPercentage through to the conflict check (previously ignored context entirely)
LowPriorityPreAddRule uses the bumped fee threshold when both feeComparisonOnly and priceBumpPercentage are set
Config flows: P2P_RPC_PRICE_BUMP_PERCENTAGE env var -> P2PConfig -> TxPoolV2Config -> PreAddContext (only for RPC path)
NULLIFIER_CONFLICT rejection error enriched with minimumPriceBumpFee and txPriorityFee fields

Test plan

15 new unit tests across tx_metadata.test.ts, nullifier_conflict_rule.test.ts, and low_priority_pre_add_rule.test.ts
Tests cover: exact threshold acceptance, below-threshold rejection, well-above threshold, 0% bump edge case, P2P path unchanged, error field population
All existing tests continue to pass

Fixes A-452

PhilWindle · 2026-02-25T10:30:35Z

yarn-project/p2p/src/mem_pools/tx_pool_v2/eviction/nullifier_conflict_rule.test.ts

+        expect(result.shouldIgnore).toBe(true);
+        expect(result.reason?.code).toBe(TxPoolRejectionCode.NULLIFIER_CONFLICT);
+        if (result.reason?.code === TxPoolRejectionCode.NULLIFIER_CONFLICT) {
+          expect(result.reason.minimumPriceBumpFee).toBe(110n);


I think we probably want it to be >= the price bump. This rejection tells me the minimum price bump is the exact fee I sent but I still got rejected.

Fixed - I changed the logic to be >= price bump.
Edge case when price bump is configured to 0 - replacement always requires paying strictly more (1 unit more)

PhilWindle · 2026-02-25T10:38:31Z

yarn-project/p2p/src/mem_pools/tx_pool_v2/tx_metadata.ts

+ * Uses integer arithmetic: `existingFee + existingFee * priceBumpPercentage / 100`.
+ */
+export function getMinimumPriceBumpFee(existingFee: bigint, priceBumpPercentage: number): bigint {
+  return existingFee + (existingFee * BigInt(priceBumpPercentage)) / 100n;


We should ensure that priceBumpPercentage is an integer before passing it to BigInt().

Fixed - I changed the type

PhilWindle · 2026-02-27T17:47:03Z

yarn-project/p2p/src/config.ts

@@ -471,7 +472,7 @@ export const p2pConfigMappings: ConfigMappingsType<P2PConfig> = {
    env: 'P2P_RPC_PRICE_BUMP_PERCENTAGE',
    description:
      'Minimum percentage fee increase required to replace an existing tx via RPC. Set to 0 to disable price bumps.',


Set to 0 to disable price bumps.

This isn't really true is it? In reality the minimum bump is 1.

fixed - updated the env variable description

# Conflicts: # docs/docs-operate/operators/reference/changelog/v4.md

AztecBot · 2026-03-03T09:55:21Z

❌ Failed to cherry-pick to v4 due to conflicts. Dispatching ClaudeBox to resolve. View backport run.

Adds a configurable percentage-based "price bump" requirement for RPC-submitted transactions that clash on nullifiers with existing pool transactions, or that need to evict the lowest-priority tx when the pool is full. This prevents spam via infinitesimally small fee increments. - When a tx arrives via RPC with nullifier conflicts, it must now pay at least X% above each conflicting tx's priority fee (default: 10%) — i.e. `>= existingFee + existingFee * bump / 100` - The same bump applies to pool-full eviction via `LowPriorityPreAddRule` - P2P gossip path is unchanged — continues using `comparePriority` (fee + hash tiebreaker) with no bump - Rejection errors now include the minimum required fee so callers know how much to bid - New env var `P2P_RPC_PRICE_BUMP_PERCENTAGE` (default: 10) controls the bump percentage - `getMinimumPriceBumpFee(existingFee, priceBumpPercentage)` helper computes the threshold using integer arithmetic: `existingFee + max(existingFee * bump / 100, 1)` — the minimum bump is always at least 1 unit, so replacement always requires paying strictly more (even with 0% bump or zero existing fee) - `priceBumpPercentage` is typed as `bigint` throughout the config chain to avoid `BigInt()` conversion issues with non-integer values - `checkNullifierConflict` accepts an optional `priceBumpPercentage` param; when set, uses fee-only `>=` comparison against the bumped threshold instead of `comparePriority` - `NullifierConflictRule` now passes `context.priceBumpPercentage` through to the conflict check (previously ignored context entirely) - `LowPriorityPreAddRule` uses the bumped fee threshold when both `feeComparisonOnly` and `priceBumpPercentage` are set - Config flows: `P2P_RPC_PRICE_BUMP_PERCENTAGE` env var -> `P2PConfig` -> `TxPoolV2Config` -> `PreAddContext` (only for RPC path) - `NULLIFIER_CONFLICT` rejection error enriched with `minimumPriceBumpFee` and `txPriorityFee` fields - 15 new unit tests across `tx_metadata.test.ts`, `nullifier_conflict_rule.test.ts`, and `low_priority_pre_add_rule.test.ts` - Tests cover: exact threshold acceptance, below-threshold rejection, well-above threshold, 0% bump edge case, P2P path unchanged, error field population - All existing tests continue to pass Fixes A-452

…o v4 (#21036) Backport of #20806 to v4. Adds a configurable percentage-based price bump requirement for RPC-submitted transactions that clash on nullifiers with existing pool transactions, or that need to evict the lowest-priority tx when the pool is full. This prevents spam via infinitesimally small fee increments. ## Conflict resolution Three files had conflicts due to `dropTransactionsProbability` (present on next, absent on v4): - `docs/docs-operate/operators/reference/changelog/v4.md` — added the price bump changelog section without the unrelated "Setup allow list" section - `yarn-project/p2p/src/client/factory.ts` — added `priceBumpPercentage` config pass-through (without `dropTransactionsProbability`) - `yarn-project/p2p/src/mem_pools/tx_pool_v2/interfaces.ts` — added `priceBumpPercentage` to type and defaults (without `dropTransactionsProbability`) ClaudeBox log: http://ci.aztec-labs.com/ff393a9b4d8e95fb-1 Co-authored-by: Michal Rzeszutko <michal.rzeszutko@gmail.com>

BEGIN_COMMIT_OVERRIDE test: update proving-real test to mbps (#20991) chore: epoch proving log analyzer (#21033) chore: update pause script to allow resume (#21032) feat: price bump for RPC transaction replacement (#20806) refactor: remove update checker, retain version checks (#20898) fix: (A-592) p2p client proposal tx collector test (#20998) refactor: use publishers-per-pod in deployments (#21039) chore: web3signer refreshes keystore (#21045) feat(sequencer): set block building limits from checkpoint limits (#20974) chore(e2e): fix e2e bot L1 tx nonce reuse (#21052) feat: Update L1 to L2 message APIs (#20913) fix: (A-589) epochs l1 reorgs test (#20999) feat(sequencer): add SEQ_MAX_TX_PER_CHECKPOINT config (#21016) fix: drop --pid=host from docker_isolate (#21081) feat: standby mode for prover broker (#21098) fix(p2p): remove default block handler in favor of block handler (#21105) feat(validator): add VALIDATOR_ env vars for independent block limits (#21060) refactor(p2p): decouple proposal validators from base class via composition (#21075) feat: additional validation in public setup allowlist (onlySelf + null msg sender) (#21122) fix: (A-591) aztecProofSubmissionEpochs incorrectly named as aztecProofSubmissionWindow (#21108) refactor(sequencer): rename SEQ_GAS_PER_BLOCK_ALLOCATION_MULTIPLIER to SEQ_PER_BLOCK_ALLOCATION_MULTIPLIER (#21125) fix: unbound variable in check_doc_references.sh with set -u (#21126) feat: calldata length validation of public setup function allowlist (#21139) fix: include mismatched values in tx metadata validation errors (#21147) feat: single-node implementation of slash-protection signer (#20894) feat: Remove non-protocol contracts from public setup allowlist (#21154) chore: More updated Alpha configuration (#21155) chore: tally slashing pruning improvements (#21161) fix: update dependencies (#20997) fix: omit bigint priceBumpPercentage from IPC config in testbench worker (#21169) refactor(p2p): (A-588) maintain sorted array in tx pool instead of sorting on read (#21079) fix(p2p): report most severe failure in runValidations (#21185) fix: use dedicated L1 account for bot bridge resume tests to avoid nonce race (#21148) fix: parse error.message in formatViemError (#21163) fix: bump lighthouse consensus client v7.1.0 -> v8.0.1 (#21170) chore: code decuplication + refactor (public setup allowlist) (#21200) END_COMMIT_OVERRIDE

feat: price bump for RPC transaction replacement

f0066fa

mrzeszutko added the backport-to-v4 label Feb 24, 2026

fixing 0% bump edge case

750fa8b

mrzeszutko changed the base branch from next to merge-train/spartan February 24, 2026 12:48

PhilWindle requested changes Feb 25, 2026

View reviewed changes

mrzeszutko added 2 commits February 26, 2026 06:44

Merge branch 'merge-train/spartan' into mr/add-price-bump-tx-replacement

d69e055

Switching comparison to >= priceBump

6258b1f

mrzeszutko requested a review from PhilWindle February 26, 2026 09:07

PhilWindle reviewed Feb 27, 2026

View reviewed changes

mrzeszutko added 2 commits March 3, 2026 08:26

Merge branch 'merge-train/spartan' into mr/add-price-bump-tx-replacement

3e37d6c

# Conflicts: # docs/docs-operate/operators/reference/changelog/v4.md

updating env variable description to match the logic

8c1752a

mrzeszutko requested a review from PhilWindle March 3, 2026 08:42

PhilWindle approved these changes Mar 3, 2026

View reviewed changes

PhilWindle merged commit 22a8254 into merge-train/spartan Mar 3, 2026
10 checks passed

PhilWindle deleted the mr/add-price-bump-tx-replacement branch March 3, 2026 09:53

AztecBot mentioned this pull request Mar 3, 2026

feat: merge-train/spartan #21034

Merged

AztecBot mentioned this pull request Mar 3, 2026

chore: backport #20806 (price bump for RPC transaction replacement) to v4 #21036

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feat: price bump for RPC transaction replacement#20806

feat: price bump for RPC transaction replacement#20806
PhilWindle merged 6 commits intomerge-train/spartanfrom
mr/add-price-bump-tx-replacement

mrzeszutko commented Feb 24, 2026 •

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mrzeszutko commented Feb 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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mrzeszutko commented Feb 24, 2026 •

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