fix: set nodes known to be absent to Empty, to differentiate from unk…

…nown nodes (#353) * fix: set nodes known to be absent to Empty, to differentiate from unknown nodes * fix failing test
ethereum · May 11, 2023 · ab52d15 · ab52d15
1 parent b02bc4f
commit ab52d15
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Showing 2 changed files with 6 additions and 3 deletions.
diff --git a/proof_test.go b/proof_test.go
@@ -637,8 +637,8 @@ func TestStatelessDeserializeMissginChildNode(t *testing.T) {
 		t.Fatal("differing commitment for child #0")
 	}
 
-	if droot.(*InternalNode).children[64] != UnknownNode(struct{}{}) {
-		t.Fatalf("non-nil child #64: %v", droot.(*InternalNode).children[64])
+	if droot.(*InternalNode).children[64] != Empty(struct{}{}) {
+		t.Fatalf("non-empty child #64: %v", droot.(*InternalNode).children[64])
 	}
 }
 

diff --git a/tree.go b/tree.go
@@ -409,7 +409,10 @@ func (n *InternalNode) CreatePath(path []byte, stemInfo stemInfo, comms []*Point
 	if len(path) == 1 {
 		switch stemInfo.stemType & 3 {
 		case extStatusAbsentEmpty:
-			// nothing to do
+			// Set child to Empty so that, in a stateless context,
+			// a node known to be absent is differentiated from an
+			// unknown node.
+			n.children[path[0]] = Empty{}
 		case extStatusAbsentOther:
 			// insert poa stem
 		case extStatusPresent: