Heimdall version v0.8.2 has been released, containing an important liveness fix. All node operators are recommended to upgrade to ensure stability.
This update addresses a bug in the block proposal process (PrepareProposal) that could cause a block producer to stall. Previously, a proposer would calculate the size of a transaction batch using a method that didn't account for all protobuf-encoding overhead. During periods of high transaction load, this could lead to a proposer creating a block that it believed was valid, but which would then be rejected by CometBFT for exceeding the maximum block size (MaxTxBytes), stalling that specific proposer.
The fix corrects this by making the proposer use the same protobuf-aware sizing function (ComputeProtoSizeForTxs) that CometBFT uses for validation. This ensures size calculations are consistent and prevents oversized blocks from being proposed.
Key points about this release:
- It is not consensus-affecting and does not require a hardfork.
- It is backwards-compatible. However, validators who do not upgrade will remain vulnerable to this stalling issue. A full upgrade for all validators is highly recommended.
## Summary The heimdall `v0.8.2` release contains a security/liveness fix for Polygon mainnet, mirroring the `v0.8.2-priv` private release. Upgrade is recommended for all node operators. ## Highlights Block-producer liveness fix in `PrepareProposal`. The proposer now sizes its proposal using the same protobuf-encoded unit CometBFT uses to validate it (`ComputeProtoSizeForTxs`) instead of raw `len(tx)`. Raw length undercounted per-tx protobuf overhead, so under high transaction load a proposer could assemble a batch that passed its own size check but exceeded `MaxTxBytes` once CometBFT re-measured it — failing proposal creation and stalling block production on that proposer. - Not consensus-affecting. Only changes which txs a proposer includes during `PrepareProposal`; `ProcessProposal`, the state transition, and block replay are untouched — no app-hash impact, no hardfork. - Backwards-compatible. Mixed-version networks are safe, but an un-upgraded validator can still stall itself while proposing, so all validators should upgrade. ## What's Changed - app/abci: size proto proposal by @marcello33 in https://github.com/0xPolygon/heimdall-v2/commit/31b356811767e4bdcd97f8c124e1f753b7eb77dd ## Full Changelog https://github.com/0xPolygon/heimdall-v2/compare/v0.8.1...v0.8.2-beta