eth_simulate Implementers' Meeting | March 31, 2025

[poojaranjan]

eth_simulate Implementers' Meeting

• Date and time in UTC March 31, 2025, 12:00 UTC
• Duration in minutes: 60 minutes
• Recurring meeting : true
• Call series : eth_simulate Implementers
• Occurrence rate : weekly
• Other optional Resources

Ideas for eth_simulateV2
PEEPanEIP#135: Eth Simulate with Oleg and Killari
https://eips.ethereum.org/EIPS/eip-4399
https://docs.login.xyz/general-information/siwe-overview
https://ethresear.ch/t/fork-choice-enforced-inclusion-lists-focil-a-simple-committee-based-inclusion-list-proposal/19870

Agenda

• [Notes from the last meeting]
• Client Implementation update
• Test
• Discuss spec for eth_simulateV2

Other comments and resources

The zoom link will be sent to the facilitator (please fill in the email and telegram)
Facilitator email: Killari@gmail.com
Facilitator telegram: @Qhuesten

[bomanaps]

Meeting Summary

Key Discussion Points

Geth Transaction Sender Fix

• Sina submitted a fix for the issue where the transaction sender appears as zero in Geth.
• The solution is considered "hacky" but is the best available option for now.
• The fix is pending merge and is targeted for the next release.

Block Timestamp Handling

• Sina observed that Geth still complains when two blocks have the same timestamp, despite previous discussions allowing timestamps to remain the same or increase.
• This flexibility was agreed upon to support chains with sub-second block times.
• Action Item: Check if Nethermind also accepts identical timestamps (to be tested).

Base Fee Encoding Mismatch (Geth vs. Nethermind)

• A hash mismatch issue was identified due to differences in RLP encoding of block headers, specifically concerning the baseFee field.

Geth Behavior:

• Encodes an extra 0x00 byte when baseFee is zero.
• Distinguishes between null (pre-EIP-1559) and non-null (post-EIP-1559) baseFee values.

Nethermind Behavior:

• Does not encode baseFee at all if it is zero (treats zero as equivalent to null).
• Does not support null values in its internal model.

Root Cause:

• The edge case arises in eth_simulate, where baseFee = 0 is allowed (unlike in consensus, where baseFee cannot be below 7).

Proposed Solution:

• Use a separate RLP encoder for eth_simulate to ensure consistency between clients.
• Sina will test if removing the extra byte resolves the hash mismatch.

State Root Mismatch Fix

• A minor fix related to the spec was implemented, and state roots now match between clients.

Tracing & Interns

• Sina has not yet worked on tracing improvements but suggested onboarding an intern to assist.
• Nethermind’s core team has limited interns, as most work on non-core projects (e.g., PhD-related research).
• Past interns were rarely assigned to core development due to complexity.

Action Items

Sina:

• Test if the baseFee RLP encoding adjustment resolves the hash mismatch.
• Follow up on merging the transaction sender fix.

Team:

• Verify Nethermind’s handling of identical block timestamps.
• Document the eth_simulate-specific RLP encoding approach for baseFee = 0.

Next Steps

• Confirm block hash alignment after the baseFee fix.
• Discuss intern resource allocation for tracing work if needed.