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Extra null check for V1 genesis #11533

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Extra null check for V1 genesis #11533

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57bd560
check for null
ak88 May 8, 2026
a2f087a
ensure initial sync
ak88 May 8, 2026
63dfe9a
ensure genesis
ak88 May 8, 2026
b4ca0b5
Add warn log and regression test for V1 genesis initialization
github-actions[bot] May 8, 2026
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2 changes: 1 addition & 1 deletion src/Nethermind/Nethermind.Xdc/QuorumCertificateManager.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -237,7 +237,7 @@ public void Initialize(XdcBlockHeader current)
{
IXdcReleaseSpec spec = _specProvider.GetXdcSpec(current);
QuorumCertificate latestQc;
if (current.Number == spec.SwitchBlock)
if (current.Number == spec.SwitchBlock || current.ExtraConsensusData is null)
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@claude claude Bot May 8, 2026

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Medium — Silent fallback without a warning log

When current.ExtraConsensusData is null on a block that is not the switch block, Initialize silently treats it as a genesis block: round is reset to 1 and a synthetic zero-round QC is constructed. This is the correct action to avoid an NPE (the original bug), but it is inconsistent with how the rest of the file handles the same condition — CommitBlock at line 95 logs a warning and returns an error for the same missing-data scenario ("Chain might be corrupt!").

Without a warning log here, chain corruption or a deserialization bug that leaves ExtraConsensusData null on a mid-chain block will produce no observable signal; the node will just silently restart consensus from round 1.

Suggested fix — add a warn log inside the branch when it isn't the switch block:

Suggested change
if (current.Number == spec.SwitchBlock || current.ExtraConsensusData is null)
if (current.Number == spec.SwitchBlock || current.ExtraConsensusData is null)
{
if (current.Number != spec.SwitchBlock && _logger.IsWarn)
_logger.Warn($"Block {current.ToString(BlockHeader.Format.FullHashAndNumber)} has no consensus data; initializing consensus from genesis state.");

Fix this →

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@claude claude Bot May 8, 2026

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The null guard is correct and prevents the NRE in the else branch. Two suggestions:

  1. Regression test — please add a test in QuorumCertificateManagerTest covering Initialize with a V1 block (ExtraConsensusData is null, Number != spec.SwitchBlock). The existing test helpers make this straightforward.

  2. Observability — a _logger.Warn on the null path (when Number != spec.SwitchBlock) would make it visible if this is ever hit unexpectedly for a V2 block due to serialization or DB issues, rather than silently resetting to round 1.

Suggested change
if (current.Number == spec.SwitchBlock || current.ExtraConsensusData is null)
if (current.Number == spec.SwitchBlock || current.ExtraConsensusData is null)
{
if (current.ExtraConsensusData is null && current.Number != spec.SwitchBlock)
if (_logger.IsWarn) _logger.Warn($"Block #{current.Number} ({current.Hash}) has no V2 consensus data, initializing consensus from V1 genesis.");

{
latestQc = new QuorumCertificate(new BlockRoundInfo(current.Hash, 0, current.Number), Array.Empty<Signature>(),
(ulong)Math.Max(0, current.Number - spec.Gap));
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