ethereum/go-ethereum · error

sub-trie ancestor not found: %x

Error message

sub-trie ancestor not found: %x

What it means

Error "sub-trie ancestor not found: %x" thrown in ethereum/go-ethereum.

Source

Thrown at trie/sync.go:312

	exist, inconsistent := s.hasNode(owner, inner, root)
	if exist {
		// The entire subtrie is already present in the database.
		return
	} else if inconsistent {
		// There is a pre-existing node with the wrong hash in DB, remove it.
		s.membatch.delNode(owner, inner)
	}
	// Assemble the new sub-trie sync request
	req := &nodeRequest{
		hash:     root,
		path:     path,
		callback: callback,
	}
	// If this sub-trie has a designated parent, link them together
	if parent != (common.Hash{}) {
		ancestor := s.nodeReqs[string(parentPath)]
		if ancestor == nil {
			panic(fmt.Sprintf("sub-trie ancestor not found: %x", parent))
		}
		ancestor.deps++
		req.parent = ancestor
	}
	s.scheduleNodeRequest(req)
}

// AddCodeEntry schedules the direct retrieval of a contract code that should not
// be interpreted as a trie node, but rather accepted and stored into the database
// as is.
func (s *Sync) AddCodeEntry(hash common.Hash, path []byte, parent common.Hash, parentPath []byte) {
	// Short circuit if the entry is empty or already known
	if hash == types.EmptyCodeHash {
		return
	}
	if s.membatch.hasCode(hash) {
		return
	}

View on GitHub (pinned to 6bb0588ad8)

Solutions

1. The scheduled sub-trie request references a parent that was never registered. Ensure parent sub-trie paths are scheduled before (or together with) their children in trie.Sync, and that path prefixes are consistent.
2. Treat this as an internal sync-scheduling bug: check that the caller derives sub-trie parent paths correctly.

Example fix

// Parent sub-trie must be scheduled first:
sync := trie.NewSync(root, db, callback, scheme)
sync.AddSubTrie(parentPath, parentPathHash, parentRoot, nil)
sync.AddSubTrie(childPath, childHash, childRoot, parentRoot) // parent known

When it happens

Trigger: trie.Sync scheduling a sub-trie request whose designated parent hash was not previously scheduled as a node request.

Common situations: Snap sync healing or state sync code scheduling child sub-tries before their ancestors.

AI-assisted analysis of ethereum/go-ethereum@6bb0588ad8 (2026-08-15). Data as JSON: /api/errors/4c5772f5ef79596a. Report an issue: GitHub.