feat(l2): allow paying fees with custom token #5024

tomip01 · 2025-10-23T18:50:24Z

Motivation

This pull request introduces support for a new transaction type, CustomFeeTransaction, we want to be able to pay fees with an ERC20 token instead of ETH.

Description

Added CustomFeeTransaction as a new variant to the Transaction enum, and updated the TxType enum and its associated methods to recognize the new type.
Enforced that CustomFeeTransaction is not allowed in P2P transaction processing, returning an error if encountered.
Modified l2_hook to deduct and refund fees according to the ERC20 tokens desired as the user

github-actions · 2025-10-23T18:53:07Z

Lines of code report

Total lines added: 638
Total lines removed: 0
Total lines changed: 638

Detailed view

+----------------------------------------------------------+-------+------+
| File                                                     | Lines | Diff |
+----------------------------------------------------------+-------+------+
| ethrex/cmd/ethrex/build_l2.rs                            | 412   | +15  |
+----------------------------------------------------------+-------+------+
| ethrex/crates/blockchain/blockchain.rs                   | 1296  | +1   |
+----------------------------------------------------------+-------+------+
| ethrex/crates/blockchain/metrics/metrics_transactions.rs | 151   | +2   |
+----------------------------------------------------------+-------+------+
| ethrex/crates/common/types/receipt.rs                    | 343   | +2   |
+----------------------------------------------------------+-------+------+
| ethrex/crates/common/types/transaction.rs                | 3147  | +310 |
+----------------------------------------------------------+-------+------+
| ethrex/crates/l2/networking/rpc/signer.rs                | 276   | +11  |
+----------------------------------------------------------+-------+------+
| ethrex/crates/l2/sdk/src/sdk.rs                          | 938   | +20  |
+----------------------------------------------------------+-------+------+
| ethrex/crates/networking/rpc/clients/eth/mod.rs          | 622   | +1   |
+----------------------------------------------------------+-------+------+
| ethrex/crates/networking/rpc/eth/fee_market.rs           | 232   | +3   |
+----------------------------------------------------------+-------+------+
| ethrex/crates/networking/rpc/types/transaction.rs        | 101   | +5   |
+----------------------------------------------------------+-------+------+
| ethrex/crates/vm/backends/levm/mod.rs                    | 614   | +2   |
+----------------------------------------------------------+-------+------+
| ethrex/crates/vm/levm/src/environment.rs                 | 94    | +1   |
+----------------------------------------------------------+-------+------+
| ethrex/crates/vm/levm/src/hooks/l2_hook.rs               | 510   | +263 |
+----------------------------------------------------------+-------+------+
| ethrex/tooling/ef_tests/state/runner/levm_runner.rs      | 441   | +1   |
+----------------------------------------------------------+-------+------+
| ethrex/tooling/ef_tests/state_v2/src/modules/runner.rs   | 207   | +1   |
+----------------------------------------------------------+-------+------+

github-actions · 2025-10-23T19:10:34Z

Benchmark Results Comparison

Benchmark Results: Push

Command	Mean [s]	Min [s]	Max [s]	Relative
`main_revm_Push`	355.1 ± 180.0	297.2	867.4	1.19 ± 0.60
`main_levm_Push`	312.9 ± 1.9	310.7	317.3	1.05 ± 0.01
`pr_revm_Push`	297.7 ± 1.8	296.1	302.6	1.00

Detailed Results

Benchmark Results: BubbleSort

Command	Mean [s]	Min [s]	Max [s]	Relative
`main_revm_BubbleSort`	4.770 ± 0.040	4.736	4.863	1.04 ± 0.01
`main_levm_BubbleSort`	4.581 ± 0.016	4.563	4.604	1.00 ± 0.01
`pr_revm_BubbleSort`	4.740 ± 0.015	4.716	4.765	1.04 ± 0.01
`pr_levm_BubbleSort`	4.575 ± 0.018	4.552	4.612	1.00

Benchmark Results: ERC20Approval

Command	Mean [s]	Min [s]	Max [s]	Relative
`main_revm_ERC20Approval`	1.552 ± 0.015	1.540	1.589	1.00 ± 0.01
`main_levm_ERC20Approval`	1.674 ± 0.014	1.657	1.698	1.08 ± 0.01
`pr_revm_ERC20Approval`	1.546 ± 0.009	1.537	1.563	1.00
`pr_levm_ERC20Approval`	1.657 ± 0.007	1.649	1.670	1.07 ± 0.01

Benchmark Results: ERC20Mint

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`main_revm_ERC20Mint`	184.5 ± 1.8	183.4	189.2	1.00 ± 0.01
`main_levm_ERC20Mint`	205.4 ± 2.1	202.7	208.6	1.12 ± 0.01
`pr_revm_ERC20Mint`	183.9 ± 1.1	182.9	185.9	1.00
`pr_levm_ERC20Mint`	205.8 ± 3.0	202.9	212.8	1.12 ± 0.02

Benchmark Results: ERC20Transfer

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`main_revm_ERC20Transfer`	354.4 ± 2.7	351.3	359.5	1.01 ± 0.01
`main_levm_ERC20Transfer`	393.5 ± 2.7	389.7	399.9	1.12 ± 0.01
`pr_revm_ERC20Transfer`	351.9 ± 2.2	348.9	357.1	1.00
`pr_levm_ERC20Transfer`	390.8 ± 1.3	388.1	392.8	1.11 ± 0.01

Benchmark Results: Factorial

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`main_revm_Factorial`	236.6 ± 4.4	233.2	244.8	1.01 ± 0.02
`main_levm_Factorial`	281.6 ± 10.8	276.7	312.1	1.20 ± 0.05
`pr_revm_Factorial`	234.2 ± 1.6	232.7	237.3	1.00
`pr_levm_Factorial`	283.2 ± 0.5	282.4	283.7	1.21 ± 0.01

Benchmark Results: FactorialRecursive

Command	Mean [s]	Min [s]	Max [s]	Relative
`main_revm_FactorialRecursive`	1.655 ± 0.034	1.587	1.702	1.00
`main_levm_FactorialRecursive`	8.384 ± 0.048	8.299	8.446	5.07 ± 0.11
`pr_revm_FactorialRecursive`	1.678 ± 0.041	1.599	1.740	1.01 ± 0.03
`pr_levm_FactorialRecursive`	8.389 ± 0.033	8.336	8.446	5.07 ± 0.11

Benchmark Results: Fibonacci

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`main_revm_Fibonacci`	213.5 ± 1.1	212.4	215.3	1.00
`main_levm_Fibonacci`	262.5 ± 4.3	255.9	269.7	1.23 ± 0.02
`pr_revm_Fibonacci`	219.0 ± 7.9	210.2	236.8	1.03 ± 0.04
`pr_levm_Fibonacci`	267.3 ± 3.2	263.5	272.7	1.25 ± 0.02

Benchmark Results: FibonacciRecursive

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`main_revm_FibonacciRecursive`	878.1 ± 6.4	867.9	890.3	1.11 ± 0.01
`main_levm_FibonacciRecursive`	788.5 ± 10.4	781.9	817.4	1.00 ± 0.02
`pr_revm_FibonacciRecursive`	885.9 ± 7.5	875.7	901.9	1.12 ± 0.01
`pr_levm_FibonacciRecursive`	787.6 ± 6.0	778.7	797.6	1.00

Benchmark Results: ManyHashes

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`main_revm_ManyHashes`	12.5 ± 0.2	12.4	12.8	1.01 ± 0.02
`main_levm_ManyHashes`	13.7 ± 0.1	13.6	13.8	1.10 ± 0.01
`pr_revm_ManyHashes`	12.4 ± 0.1	12.4	12.7	1.00
`pr_levm_ManyHashes`	13.9 ± 0.4	13.6	14.8	1.12 ± 0.03

Benchmark Results: MstoreBench

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`main_revm_MstoreBench`	269.4 ± 3.4	266.3	277.1	1.06 ± 0.01
`main_levm_MstoreBench`	253.5 ± 0.9	252.1	254.9	1.00
`pr_revm_MstoreBench`	271.2 ± 8.5	265.7	292.6	1.07 ± 0.03
`pr_levm_MstoreBench`	255.6 ± 3.1	252.7	261.4	1.01 ± 0.01

Benchmark Results: Push

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`main_revm_Push`	355.1 ± 180.0	297.2	867.4	1.19 ± 0.60
`main_levm_Push`	312.9 ± 1.9	310.7	317.3	1.05 ± 0.01
`pr_revm_Push`	297.7 ± 1.8	296.1	302.6	1.00
`pr_levm_Push`	311.9 ± 9.3	307.3	338.4	1.05 ± 0.03

Benchmark Results: SstoreBench_no_opt

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
`main_revm_SstoreBench_no_opt`	223.3 ± 1.0	222.2	225.8	2.64 ± 0.04
`main_levm_SstoreBench_no_opt`	84.7 ± 2.1	81.9	88.2	1.00 ± 0.03
`pr_revm_SstoreBench_no_opt`	224.6 ± 3.7	222.7	234.8	2.65 ± 0.06
`pr_levm_SstoreBench_no_opt`	84.7 ± 1.2	83.1	87.1	1.00

tomip01 · 2025-10-28T12:18:03Z

Requested some changes in the code, and finally, include official documentation for:

An overview of the feature

Operator documentation on how to launch a network with a fee token

I see that we are missing an IFeeToken interface for IERC20, IERC20L2 contracts to implement to be a valid fee token. Is there a reason this was not done that way?

Added IFeeToken interface here 4441cfb
Added docs here 231ca50

gianbelinche · 2025-10-29T13:46:06Z

docs/l2/fundamentals/fee_token.md

+```rust
+use ethrex_l2_sdk::{build_generic_tx, send_generic_transaction};
+use ethrex_rpc::clients::eth::Overrides;
+use ethrex_common::types::TxType;
+let mut tx = build_generic_tx(
+    l2_client,
+    TxType::FeeToken,
+    recipient,
+    origin,
+    ethrex_common::Bytes::default(),
+    Overrides {
+        fee_token: Some(fee_token),
+        value: Some(value),
+        ..Default::default()
+    },
+)
+.await;
+
+let tx_hash = send_generic_transaction(l2_client, tx, signer)
+    .await;
+
+```


Can you add a complete example on how to do this.
It doesn't specify how to create l2_client and signer.
Maybe even deploying the fee_token if possible

Right! Let me know what you think about this a6b20e3

avilagaston9 · 2025-10-29T17:59:22Z

crates/l2/tests/tests.rs

+        "{test}: Priority fee mismatch"
+    );
+
+    if std::env::var("INTEGRATION_TEST_SKIP_FEE_VAULTS_CHECK").is_err() {


The Operator and L1 vault balances must always be balance_before - balance_after = fee, as the fee will be 0 if it is not active. The only vault that should be under the env var is the base fee vault as it can be burn depending on the network configuration, but for that we have the INTEGRATION_TEST_SKIP_BASE_FEE_VAULT_CHECK already.

Done 4c67d94

crates/vm/levm/src/hooks/l2_hook.rs

avilagaston9 · 2025-10-29T18:37:09Z

docs/l2/fundamentals/fee_token.md

+## Operator Workflow
+
+1. Deploy or reuse an `IFeeToken` implementation and note its L2 address.
+2. Instantiate an `EthClient` and a signer (local or remote) that will send the transaction.


Sending a transaction is not part of the Operator Workflow.

Let's add a warning explaining what is missing.

Co-authored-by: Avila Gastón <[email protected]>

This reverts commit 452a134.

tomip01 added 15 commits October 21, 2025 14:01

add custom fee token tx

9c23130

first approach l2 hook

e6890f9

basic custom fee token test, missing correctness

c146fdb

some advances on test

934be30

fix tx type check

21b9f35

change custom fee tx to 0xfd

6ac9b51

prevent recursion

2e937ce

some advances, exeuctin sol function, failing on acc updates

fce3ffc

succeeding internal hook txs

36139db

working fees, failing eth value

d3f6ebd

fix pks and sks

d7bd248

test passing with fee vault

6c8f05c

all working, missing LOTS of refactors

5a27a64

remove dbgs

ac9f885

Merge branch 'fee_token_2' into fee_token_3

d2c5f97

github-actions bot assigned tomip01 Oct 23, 2025

github-actions bot added the L2 Rollup client label Oct 23, 2025

github-project-automation bot added this to ethrex_l2 Oct 23, 2025

fix merge main on tests

95cc43b

tomip01 added 9 commits October 23, 2025 16:46

some refactors, working

e4e5d14

fix coinbase diminish fee

923e6cc

l2 hook refactors

a215f25

more refactors

d896d25

refactor contracts

5c67a8d

refactor tests

51cd21e

fix runner compile

2db97e6

add more pk

e8410af

update pk tests

dbbd0d8

use IFeeToken and fix l2 dev job

4441cfb

tomip01 requested a review from jrchatruc as a code owner October 28, 2025 04:54

tomip01 added 3 commits October 28, 2025 02:01

add fee token docs

231ca50

restore makefile

61b616b

remove step docs

9984753

tomip01 added 7 commits October 28, 2025 09:25

Merge branch 'fee_token_2' into fee_token_3

8f6f416

Merge branch 'fee_token_2' into fee_token_3

9138917

Merge branch 'fee_token_2' into fee_token_3

c2cb4c8

iclude fee token tx in p2p

a3d2f54

try fix based integration test

9fa147c

Merge branch 'fee_token_2' into fee_token_3

e3e0a31

Merge branch 'fee_token_2' into fee_token_3

4410cc1

gianbelinche reviewed Oct 29, 2025

View reviewed changes

more detail docs

a6b20e3

avilagaston9 reviewed Oct 29, 2025

View reviewed changes

tomip01 and others added 14 commits October 30, 2025 09:35

first approach on fee registry

a43e5c5

use restrict allowance for token registry

c888453

Update crates/vm/levm/src/hooks/l2_hook.rs

85620b5

Co-authored-by: Avila Gastón <[email protected]>

make only base fee vault check optionals

4c67d94

restore makefile

e4c0412

Merge branch 'fee_token_2' into fee_token_3

7b67f43

add cargo lock

b3e5696

Merge branch 'fee_token_2' into fee_token_3

8e6ab6f

Merge branch 'fee_token_2' into fee_token_3

885a0a7

fix merge main

28f5d6f

refactor: use fixed address

2be365d

refactor: remove old code

13ec266

restore genesis

452a134

Revert "restore genesis"

477927e

This reverts commit 452a134.

feat(l2): allow paying fees with custom token #5024

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feat(l2): allow paying fees with custom token #5024

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Benchmark Results Comparison

Benchmark Results: Push

Benchmark Results: BubbleSort

Benchmark Results: ERC20Approval

Benchmark Results: ERC20Mint

Benchmark Results: ERC20Transfer

Benchmark Results: Factorial

Benchmark Results: FactorialRecursive

Benchmark Results: Fibonacci

Benchmark Results: FibonacciRecursive

Benchmark Results: ManyHashes

Benchmark Results: MstoreBench

Benchmark Results: Push

Benchmark Results: SstoreBench_no_opt

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