blockchain, node/cn: bound the hash-based header ancestor lookup - #1010
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hyunsooda wants to merge 2 commits into
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blockchain, node/cn: bound the hash-based header ancestor lookup#1010hyunsooda wants to merge 2 commits into
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The hash-mode advance in the header request handler verified descent by walking Skip+1 parents and pre-allocating a Skip-sized hash slice, so a request whose answer is bounded by Amount could cost work proportional to the chain height. Ported go-ethereum's GetAncestor (#16946, released in v1.8.11, after Kaia's fork point): a canonical ancestor is resolved by number, and the non-canonical walk is bounded by a per-request budget. GetBlockHashesFromHash had no other caller and is removed, as upstream did. Constraint: the response shapes verified by TestGetBlockHeaders must not change Rejected: cap query.Skip instead | the cost no longer depends on Skip, and an arbitrary cap risks rejecting legitimate skeleton sync requests Directive: GetAncestor is a verbatim port; keep it diffable against upstream Confidence: high Scope-risk: narrow Not-tested: upstream's companion change that fetches later origins with GetHeader(hash, number) instead of GetHeaderByHash is deliberately not ported Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
ian0371
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Aug 7, 2026
2dvorak
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Aug 10, 2026
2dvorak
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The new GetAncestor logic looks correct, but TestGetAncestor never actually exercises the budget running out. The 0xdead case stops after one hop (GetHeader returns nil), so if *maxNonCanonical == 0 { return ... } in headerchain.go:276 is never reached by any test — and that line is the whole point of the change.
Could we add a case for it?
TestGetAncestor's non-canonical case uses a hash with no header, so the walk gives up on its first hop and never reaches the budget guard. Add a case with a branch that outlasts the budget, and assert the walk ends with the budget spent rather than on a missing header. Confidence: high Scope-risk: narrow Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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@2dvorak Thanks, added. |
2dvorak
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Aug 11, 2026
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Proposed changes
The hash-mode advance in the header request handler verified descent by walking
Skip+1parents and pre-allocating aSkip-sized hash slice, so a request whose answer is bounded byAmountcould cost work proportional to the chain height. This ports go-ethereum'sGetAncestor(#16946, released in v1.8.11, after Kaia's fork point): a canonical ancestor is resolved by number, and the non-canonical walk is bounded by a per-request budget.GetBlockHashesFromHashhad no other caller and is removed, as upstream did.Types of changes
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I have read the CLA Document and I hereby sign the CLAin first time contribute after having read CLA$ make test)Related issues
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