Fix QBFT ProposalPayload backward compatibility with pre-26.1.0 Besu versions#9977
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jframe merged 5 commits intobesu-eth:mainfrom Mar 6, 2026
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ProposalPayload.readBlockAccessList() did not check isEndOfCurrentList() before calling nextIsNull(). When a pre-26.1.0 node sends a proposal without the blockAccessList field, the RLP cursor is at end-of-list after reading the block, but nextIsNull() peeks at the next byte outside the payload list (the 65-byte signature), which is a LONG_ELEMENT not a null, causing BlockAccessListDecoder.decode() to call enterList() on it and throw an RLPException. Fix adds the isEndOfCurrentList() guard to return Optional.empty() for messages in the old format, and adds a regression test that encodes a proposal in the pre-26.1.0 wire format and verifies it decodes correctly. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> Signed-off-by: Jason Frame <jason.frame@consensys.net>
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Pull request overview
Fixes QBFT ProposalPayload decoding to be backward-compatible with pre-26.1.0 nodes that omit the blockAccessList RLP field, avoiding mis-parsing the following signature bytes.
Changes:
- Add an
isEndOfCurrentList()guard inProposalPayload.readBlockAccessList()to returnOptional.empty()for legacy payloads. - Add a regression test that encodes a legacy-format
ProposalPayload(withoutblockAccessList) and verifies successful decode.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| consensus/qbft-core/src/main/java/org/hyperledger/besu/consensus/qbft/core/payload/ProposalPayload.java | Adds end-of-list guard to safely handle old payload format without blockAccessList. |
| consensus/qbft-core/src/test/java/org/hyperledger/besu/consensus/qbft/core/messagewrappers/ProposalTest.java | Adds regression test covering decode of legacy proposal payloads. |
...ore/src/test/java/org/hyperledger/besu/consensus/qbft/core/messagewrappers/ProposalTest.java
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…us/qbft/core/messagewrappers/ProposalTest.java Update comment with correct number of items for each payload Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Signed-off-by: Jason Frame <jasonwframe@gmail.com>
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> Signed-off-by: Jason Frame <jason.frame@consensys.net>
macfarla
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Mar 6, 2026
jframe
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Summary
ProposalPayload.readBlockAccessList()was missing anisEndOfCurrentList()guard before callingnextIsNull()blockAccessListfield, the RLP cursor sits at end-of-list after reading the block.nextIsNull()then peeks at the next byte outside the payload list — the 65-byte signature — which is aLONG_ELEMENT, not null. This causesBlockAccessListDecoder.decode()to callenterList()on the signature and throw:RLPException: Expected current item to be a list, but it is: LONG_ELEMENTisEndOfCurrentList()check to returnOptional.empty()for old-format messagesProposalPayloadin the pre-26.1.0 wire format (withoutblockAccessList) using an anonymous subclass and verifies it decodes correctlyBackground
The
blockAccessListfield was added toProposalPayloadin 26.1.0 (commita07c7bf65a2). Networks running mixed 26.1.0+/pre-26.1.0 validators would hit this crash whenever an older node sent a proposal.Test plan
./gradlew :consensus:qbft-core:test --tests "org.hyperledger.besu.consensus.qbft.core.messagewrappers.ProposalTest"🤖 Generated with Claude Code