fix: Strip group-depth from GC

trie/bintrie/binary_node.go

@@ -27,19 +27,8 @@ const (
 	NodeTypeBytes  = 1   // Size of node type prefix in serialization
 	HashSize       = 32  // Size of a hash in bytes
 	StemBitmapSize = 32  // Size of the bitmap in a stem node (256 values = 32 bytes)
-
-	// MaxGroupDepth is the maximum allowed group depth for InternalNode serialization.
-	MaxGroupDepth = 8
 )
 
-// BitmapSizeForDepth returns the bitmap size in bytes for a given group depth.
-func BitmapSizeForDepth(groupDepth int) int {
-	if groupDepth <= 3 {
-		return 1
-	}
-	return 1 << (groupDepth - 3)
-}
-
 const (
 	nodeTypeStem = iota + 1
 	nodeTypeInternal

trie/bintrie/binary_node_test.go

@@ -23,8 +23,8 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 )
 
-// TestSerializeDeserializeInternalNode tests serialization and deserialization of InternalNode
-// with the grouped subtree format through NodeStore.
+// TestSerializeDeserializeInternalNode tests flat 65-byte serialization and
+// deserialization of InternalNode through NodeStore.
 func TestSerializeDeserializeInternalNode(t *testing.T) {
 	leftHash := common.HexToHash("0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef")
 	rightHash := common.HexToHash("0xfedcba0987654321fedcba0987654321fedcba0987654321fedcba0987654321")
@@ -39,30 +39,25 @@ func TestSerializeDeserializeInternalNode(t *testing.T) {
 	rootNode.right = rightRef
 	s.SetRoot(rootRef)
 
-	// Serialize the node with default group depth of 8
-	serialized := s.SerializeNode(rootRef, MaxGroupDepth)
+	// Serialize the node — flat 65-byte format
+	serialized := s.SerializeNode(rootRef)
 
-	// Check the serialized format
+	// Check the serialized format: [type(1)][leftHash(32)][rightHash(32)]
 	if serialized[0] != nodeTypeInternal {
 		t.Errorf("Expected type byte to be %d, got %d", nodeTypeInternal, serialized[0])
 	}
-	if serialized[1] != MaxGroupDepth {
-		t.Errorf("Expected group depth to be %d, got %d", MaxGroupDepth, serialized[1])
-	}
 
-	bitmapSize := BitmapSizeForDepth(MaxGroupDepth)
-	expectedLen := 1 + 1 + bitmapSize + 2*HashSize
+	expectedLen := NodeTypeBytes + 2*HashSize // 1 + 64 = 65
 	if len(serialized) != expectedLen {
 		t.Errorf("Expected serialized length to be %d, got %d", expectedLen, len(serialized))
 	}
 
-	// Check bitmap bits
-	bitmap := serialized[2 : 2+bitmapSize]
-	if bitmap[0]&0x80 == 0 {
-		t.Error("Expected bit 0 to be set in bitmap (left child)")
+	// Check that left and right hashes are embedded directly
+	if !bytes.Equal(serialized[NodeTypeBytes:NodeTypeBytes+HashSize], leftHash[:]) {
+		t.Error("Left hash not found at expected position")
 	}
-	if bitmap[16]&0x80 == 0 {
-		t.Error("Expected bit 128 to be set in bitmap (right child)")
+	if !bytes.Equal(serialized[NodeTypeBytes+HashSize:], rightHash[:]) {
+		t.Error("Right hash not found at expected position")
 	}
 
 	// Deserialize into a new store
@@ -82,35 +77,21 @@ func TestSerializeDeserializeInternalNode(t *testing.T) {
 		t.Errorf("Expected depth 0, got %d", internalNode.depth)
 	}
 
-	// Navigate to position 0 (8 left turns) to find the left hash
-	node0 := navigateToLeafRef(ds, deserialized, 0, 8)
-	if ds.ComputeHash(node0) != leftHash {
-		t.Errorf("Left hash mismatch: expected %x, got %x", leftHash, ds.ComputeHash(node0))
+	// Left child should be a HashedNode with the correct hash
+	if internalNode.left.Kind() != KindHashed {
+		t.Fatalf("Expected left child to be KindHashed, got %d", internalNode.left.Kind())
+	}
+	if ds.ComputeHash(internalNode.left) != leftHash {
+		t.Errorf("Left hash mismatch: expected %x, got %x", leftHash, ds.ComputeHash(internalNode.left))
 	}
 
-	// Navigate to position 128 (right, then 7 lefts) to find the right hash
-	node128 := navigateToLeafRef(ds, deserialized, 128, 8)
-	if ds.ComputeHash(node128) != rightHash {
-		t.Errorf("Right hash mismatch: expected %x, got %x", rightHash, ds.ComputeHash(node128))
+	// Right child should be a HashedNode with the correct hash
+	if internalNode.right.Kind() != KindHashed {
+		t.Fatalf("Expected right child to be KindHashed, got %d", internalNode.right.Kind())
 	}
-}
-
-// navigateToLeafRef navigates to a specific position in the tree using NodeStore.
-func navigateToLeafRef(s *NodeStore, ref NodeRef, position, depth int) NodeRef {
-	cur := ref
-	for d := 0; d < depth; d++ {
-		if cur.Kind() != KindInternal {
-			return cur
-		}
-		in := s.getInternal(cur.Index())
-		bit := (position >> (depth - 1 - d)) & 1
-		if bit == 0 {
-			cur = in.left
-		} else {
-			cur = in.right
-		}
+	if ds.ComputeHash(internalNode.right) != rightHash {
+		t.Errorf("Right hash mismatch: expected %x, got %x", rightHash, ds.ComputeHash(internalNode.right))
 	}
-	return cur
 }
 
 // TestSerializeDeserializeStemNode tests serialization and deserialization of StemNode through NodeStore.
@@ -135,7 +116,7 @@ func TestSerializeDeserializeStemNode(t *testing.T) {
 	}
 
 	// Serialize the node
-	serialized := s.SerializeNode(ref, MaxGroupDepth)
+	serialized := s.SerializeNode(ref)
 
 	// Check the serialized format
 	if serialized[0] != nodeTypeStem {
@@ -214,8 +195,8 @@ func TestDeserializeInvalidType(t *testing.T) {
 // TestDeserializeInvalidLength tests deserialization with invalid data length.
 func TestDeserializeInvalidLength(t *testing.T) {
 	s := NewNodeStore()
-	// InternalNode with valid type byte and group depth but too short for bitmap
-	invalidData := []byte{nodeTypeInternal, 8, 0, 0} // Too short for bitmap (needs 32 bytes)
+	// InternalNode with valid type byte but wrong length (needs exactly 65 bytes)
+	invalidData := []byte{nodeTypeInternal, 0, 0, 0}
 
 	_, err := s.DeserializeNode(invalidData, 0)
 	if err == nil {

trie/bintrie/hashed_node_test.go

@@ -95,7 +95,7 @@ func TestHashedNodeInsertValuesAtStem(t *testing.T) {
 			sn.setValue(byte(i), v)
 		}
 	}
-	serialized := rs.SerializeNode(ref, MaxGroupDepth)
+	serialized := rs.SerializeNode(ref)
 
 	validResolver := func(path []byte, hash common.Hash) ([]byte, error) {
 		return serialized, nil

trie/bintrie/internal_node_test.go

@@ -90,7 +90,7 @@ func TestInternalNodeGetWithResolver(t *testing.T) {
 			ref := rs.newStemRef(stem, 1)
 			sn := rs.getStem(ref.Index())
 			sn.setValue(5, common.HexToHash("0xabcd").Bytes())
-			return rs.SerializeNode(ref, MaxGroupDepth), nil
+			return rs.SerializeNode(ref), nil
 		}
 		return nil, errors.New("node not found")
 	}
@@ -290,7 +290,7 @@ func TestInternalNodeCollectNodes(t *testing.T) {
 		collectedPaths = append(collectedPaths, pathCopy)
 	}
 
-	err := s.CollectNodes(s.Root(), []byte{1}, flushFn, MaxGroupDepth)
+	err := s.CollectNodes(s.Root(), []byte{1}, flushFn)
 	if err != nil {
 		t.Fatalf("Failed to collect nodes: %v", err)
 	}

trie/bintrie/iterator.go

@@ -193,7 +193,7 @@ func (it *binaryNodeIterator) Path() []byte {
 
 // NodeBlob returns the serialized bytes of the current node.
 func (it *binaryNodeIterator) NodeBlob() []byte {
-	return it.store.SerializeNode(it.current, MaxGroupDepth)
+	return it.store.SerializeNode(it.current)
 }
 
 // Leaf returns true iff the current node is a leaf node.

trie/bintrie/iterator_test.go

@@ -31,7 +31,6 @@ func makeTrie(t *testing.T, entries [][2]common.Hash) *BinaryTrie {
 	tr := &BinaryTrie{
 		store:      store,
 		tracer:     trie.NewPrevalueTracer(),
-		groupDepth: MaxGroupDepth,
 	}
 	for _, kv := range entries {
 		if err := store.Insert(kv[0][:], kv[1][:], nil); err != nil {
@@ -66,7 +65,6 @@ func TestIteratorEmptyTrie(t *testing.T) {
 	tr := &BinaryTrie{
 		store:      NewNodeStore(),
 		tracer:     trie.NewPrevalueTracer(),
-		groupDepth: MaxGroupDepth,
 	}
 	it, err := newBinaryNodeIterator(tr, nil)
 	if err != nil {

trie/bintrie/stem_node_test.go

@@ -320,7 +320,7 @@ func TestStemNodeCollectNodes(t *testing.T) {
 		collectedPaths = append(collectedPaths, pathCopy)
 	}
 
-	err := s.CollectNodes(s.Root(), []byte{0, 1, 0}, flushFn, MaxGroupDepth)
+	err := s.CollectNodes(s.Root(), []byte{0, 1, 0}, flushFn)
 	if err != nil {
 		t.Fatalf("Failed to collect nodes: %v", err)
 	}

trie/bintrie/store_commit.go

@@ -98,86 +98,20 @@ func (s *NodeStore) hashInternal(idx uint32) common.Hash {
 
 // --- Serialization ---
 
-// countSubtreeChildren counts non-empty children at the bottom layer of a subtree.
-func (s *NodeStore) countSubtreeChildren(ref NodeRef, remainingDepth int) int {
-	if remainingDepth == 0 {
-		if ref.IsEmpty() {
-			return 0
-		}
-		return 1
-	}
-	if ref.Kind() == KindInternal {
-		node := s.getInternal(ref.Index())
-		return s.countSubtreeChildren(node.left, remainingDepth-1) + s.countSubtreeChildren(node.right, remainingDepth-1)
-	}
-	if ref.IsEmpty() {
-		return 0
-	}
-	return 1
-}
-
-// serializeSubtreeDirect writes child hashes directly into the serialized buffer.
-func (s *NodeStore) serializeSubtreeDirect(ref NodeRef, remainingDepth int, position int, absoluteDepth int, bitmap []byte, out []byte, hashOffset *int) {
-	if remainingDepth == 0 {
-		if ref.IsEmpty() {
-			return
-		}
-		bitmap[position/8] |= 1 << (7 - (position % 8))
-		h := s.ComputeHash(ref)
-		copy(out[*hashOffset:*hashOffset+HashSize], h[:])
-		*hashOffset += HashSize
-		return
-	}
-
-	if ref.Kind() == KindInternal {
-		node := s.getInternal(ref.Index())
-		leftPos := position * 2
-		rightPos := position*2 + 1
-		s.serializeSubtreeDirect(node.left, remainingDepth-1, leftPos, absoluteDepth+1, bitmap, out, hashOffset)
-		s.serializeSubtreeDirect(node.right, remainingDepth-1, rightPos, absoluteDepth+1, bitmap, out, hashOffset)
-		return
-	}
-
-	if ref.IsEmpty() {
-		return
-	}
-
-	// Leaf (StemNode or HashedNode) at a non-zero remaining depth: compute its position.
-	leafPos := position
-	if ref.Kind() == KindStem {
-		sn := s.getStem(ref.Index())
-		for d := 0; d < remainingDepth; d++ {
-			bit := sn.Stem[(absoluteDepth+d)/8] >> (7 - ((absoluteDepth + d) % 8)) & 1
-			leafPos = leafPos*2 + int(bit)
-		}
-	} else {
-		leafPos = position << remainingDepth
-	}
-	bitmap[leafPos/8] |= 1 << (7 - (leafPos % 8))
-	h := s.ComputeHash(ref)
-	copy(out[*hashOffset:*hashOffset+HashSize], h[:])
-	*hashOffset += HashSize
-}
-
-// SerializeNode serializes a node referenced by ref.
-func (s *NodeStore) SerializeNode(ref NodeRef, groupDepth int) []byte {
-	if groupDepth < 1 || groupDepth > MaxGroupDepth {
-		panic("groupDepth must be between 1 and 8")
-	}
-
+// SerializeNode serializes a node referenced by ref into the flat format:
+//   - InternalNode: [nodeTypeInternal(1)][leftHash(32)][rightHash(32)] = 65 bytes
+//   - StemNode:     [nodeTypeStem(1)][stem(31)][bitmap(32)][valueData(variable)]
+func (s *NodeStore) SerializeNode(ref NodeRef) []byte {
 	switch ref.Kind() {
 	case KindInternal:
 		node := s.getInternal(ref.Index())
-		bitmapSize := BitmapSizeForDepth(groupDepth)
-		hashCount := s.countSubtreeChildren(ref, groupDepth)
-		serializedLen := NodeTypeBytes + 1 + bitmapSize + hashCount*HashSize
-		serialized := make([]byte, serializedLen)
+		var serialized [NodeTypeBytes + HashSize + HashSize]byte
 		serialized[0] = nodeTypeInternal
-		serialized[1] = byte(groupDepth)
-		bitmap := serialized[2 : 2+bitmapSize]
-		hashOffset := 2 + bitmapSize
-		s.serializeSubtreeDirect(ref, groupDepth, 0, int(node.depth), bitmap, serialized, &hashOffset)
-		return serialized
+		lh := s.ComputeHash(node.left)
+		rh := s.ComputeHash(node.right)
+		copy(serialized[NodeTypeBytes:NodeTypeBytes+HashSize], lh[:])
+		copy(serialized[NodeTypeBytes+HashSize:], rh[:])
+		return serialized[:]
 
 	case KindStem:
 		sn := s.getStem(ref.Index())
@@ -215,27 +149,23 @@ func (s *NodeStore) deserializeNode(serialized []byte, depth int, hn common.Hash
 
 	switch serialized[0] {
 	case nodeTypeInternal:
-		if len(serialized) < NodeTypeBytes+1 {
+		if len(serialized) != NodeTypeBytes+2*HashSize {
 			return EmptyRef, errInvalidSerializedLength
 		}
-		groupDepth := int(serialized[1])
-		if groupDepth < 1 || groupDepth > MaxGroupDepth {
-			return EmptyRef, errors.New("invalid group depth")
-		}
-		bitmapSize := BitmapSizeForDepth(groupDepth)
-		if len(serialized) < NodeTypeBytes+1+bitmapSize {
-			return EmptyRef, errInvalidSerializedLength
-		}
-		bitmap := serialized[2 : 2+bitmapSize]
-		hashData := serialized[2+bitmapSize:]
+		var leftHash, rightHash common.Hash
+		copy(leftHash[:], serialized[NodeTypeBytes:NodeTypeBytes+HashSize])
+		copy(rightHash[:], serialized[NodeTypeBytes+HashSize:])
 
-		hashIdx := 0
-		ref, err := s.deserializeSubtree(groupDepth, 0, depth, bitmap, hashData, &hashIdx, mustRecompute)
-		if err != nil {
-			return EmptyRef, err
-		}
-		if ref.Kind() == KindInternal && !mustRecompute {
-			s.getInternal(ref.Index()).hash = hn
+		leftRef := s.newHashedRef(leftHash)
+		rightRef := s.newHashedRef(rightHash)
+
+		ref := s.newInternalRef(depth)
+		node := s.getInternal(ref.Index())
+		node.left = leftRef
+		node.right = rightRef
+		if !mustRecompute {
+			node.hash = hn
+			node.mustRecompute = false
 		}
 		return ref, nil
 
@@ -271,167 +201,34 @@ func (s *NodeStore) deserializeNode(serialized []byte, depth int, hn common.Hash
 	}
 }
 
-func (s *NodeStore) deserializeSubtree(remainingDepth int, position int, nodeDepth int, bitmap []byte, hashData []byte, hashIdx *int, mustRecompute bool) (NodeRef, error) {
-	if remainingDepth == 0 {
-		if bitmap[position/8]>>(7-(position%8))&1 == 1 {
-			if len(hashData) < (*hashIdx+1)*HashSize {
-				return EmptyRef, errInvalidSerializedLength
-			}
-			hash := common.BytesToHash(hashData[*hashIdx*HashSize : (*hashIdx+1)*HashSize])
-			*hashIdx++
-			return s.newHashedRef(hash), nil
-		}
-		return EmptyRef, nil
-	}
-
-	leftPos := position * 2
-	rightPos := position*2 + 1
-
-	left, err := s.deserializeSubtree(remainingDepth-1, leftPos, nodeDepth+1, bitmap, hashData, hashIdx, true)
-	if err != nil {
-		return EmptyRef, err
-	}
-	right, err := s.deserializeSubtree(remainingDepth-1, rightPos, nodeDepth+1, bitmap, hashData, hashIdx, true)
-	if err != nil {
-		return EmptyRef, err
-	}
-
-	if left.IsEmpty() && right.IsEmpty() {
-		return EmptyRef, nil
-	}
-
-	if nodeDepth > 248 {
-		panic("node depth exceeds maximum binary trie depth")
-	}
-	idx := s.allocInternal()
-	n := s.getInternal(idx)
-	n.depth = uint8(nodeDepth)
-	n.left = left
-	n.right = right
-	n.mustRecompute = mustRecompute
-	return MakeRef(KindInternal, idx), nil
-}
-
 // --- CollectNodes (Commit) ---
 
-// CollectNodes traverses the trie, flushing nodes at group boundaries.
-func (s *NodeStore) CollectNodes(ref NodeRef, path []byte, flushfn NodeFlushFn, groupDepth int) error {
-	if groupDepth < 1 || groupDepth > MaxGroupDepth {
-		return errors.New("groupDepth must be between 1 and 8")
-	}
-	buf := make([]byte, len(path), len(path)+MaxGroupDepth+1)
-	copy(buf, path)
-	return s.collectNodesBuf(ref, buf, flushfn, groupDepth)
-}
-
-func (s *NodeStore) collectNodesBuf(ref NodeRef, buf []byte, flushfn NodeFlushFn, groupDepth int) error {
+// CollectNodes traverses the trie, serializing and flushing each node via flushfn.
+// Children are flushed before their parents (post-order traversal).
+func (s *NodeStore) CollectNodes(ref NodeRef, path []byte, flushfn NodeFlushFn) error {
 	switch ref.Kind() {
+	case KindEmpty:
+		return nil
 	case KindInternal:
 		node := s.getInternal(ref.Index())
-		if int(node.depth)%groupDepth == 0 {
-			if err := s.collectChildGroupsBuf(ref, buf, flushfn, groupDepth, groupDepth-1); err != nil {
-				return err
-			}
-			serialized := s.SerializeNode(ref, groupDepth)
-			flushfn(buf, s.ComputeHash(ref), serialized)
-			return nil
+		if err := s.CollectNodes(node.left, append(path, 0), flushfn); err != nil {
+			return err
 		}
-		return s.collectChildGroupsBuf(ref, buf, flushfn, groupDepth, groupDepth-(int(node.depth)%groupDepth)-1)
-
+		if err := s.CollectNodes(node.right, append(path, 1), flushfn); err != nil {
+			return err
+		}
+		flushfn(path, s.ComputeHash(ref), s.SerializeNode(ref))
+		return nil
 	case KindStem:
-		serialized := s.SerializeNode(ref, groupDepth)
-		flushfn(buf, s.ComputeHash(ref), serialized)
+		flushfn(path, s.ComputeHash(ref), s.SerializeNode(ref))
 		return nil
-
-	case KindHashed, KindEmpty:
-		return nil
-
+	case KindHashed:
+		return nil // Already committed
 	default:
-		return fmt.Errorf("collectNodesBuf: unexpected kind %d", ref.Kind())
+		return fmt.Errorf("CollectNodes: unexpected kind %d", ref.Kind())
 	}
 }
 
-func (s *NodeStore) collectChildGroupsBuf(ref NodeRef, buf []byte, flushfn NodeFlushFn, groupDepth int, remainingLevels int) error {
-	if ref.Kind() != KindInternal {
-		return nil
-	}
-	node := s.getInternal(ref.Index())
-	saved := len(buf)
-	childDepth := int(node.depth) + 1
-
-	if remainingLevels == 0 {
-		if !node.left.IsEmpty() {
-			buf = append(buf, 0)
-			if err := s.collectNodesBuf(node.left, buf, flushfn, groupDepth); err != nil {
-				return err
-			}
-			buf = buf[:saved]
-		}
-		if !node.right.IsEmpty() {
-			buf = append(buf, 1)
-			if err := s.collectNodesBuf(node.right, buf, flushfn, groupDepth); err != nil {
-				return err
-			}
-		}
-		return nil
-	}
-
-	// Left child
-	if !node.left.IsEmpty() {
-		if node.left.Kind() == KindInternal {
-			buf = append(buf, 0)
-			if err := s.collectChildGroupsBuf(node.left, buf, flushfn, groupDepth, remainingLevels-1); err != nil {
-				return err
-			}
-			buf = buf[:saved]
-		} else {
-			buf = append(buf, 0)
-			buf = s.extendPathBuf(buf, node.left, remainingLevels, childDepth)
-			if err := s.collectNodesBuf(node.left, buf, flushfn, groupDepth); err != nil {
-				return err
-			}
-			buf = buf[:saved]
-		}
-	}
-
-	// Right child
-	if !node.right.IsEmpty() {
-		if node.right.Kind() == KindInternal {
-			buf = append(buf, 1)
-			if err := s.collectChildGroupsBuf(node.right, buf, flushfn, groupDepth, remainingLevels-1); err != nil {
-				return err
-			}
-		} else {
-			buf = append(buf, 1)
-			buf = s.extendPathBuf(buf, node.right, remainingLevels, childDepth)
-			if err := s.collectNodesBuf(node.right, buf, flushfn, groupDepth); err != nil {
-				return err
-			}
-		}
-	}
-
-	return nil
-}
-
-// extendPathBuf extends the path buffer to the group's leaf boundary.
-func (s *NodeStore) extendPathBuf(buf []byte, ref NodeRef, remainingLevels int, absoluteDepth int) []byte {
-	if remainingLevels <= 0 {
-		return buf
-	}
-	if ref.Kind() == KindStem {
-		sn := s.getStem(ref.Index())
-		for d := 0; d < remainingLevels; d++ {
-			bit := sn.Stem[(absoluteDepth+d)/8] >> (7 - ((absoluteDepth + d) % 8)) & 1
-			buf = append(buf, bit)
-		}
-	} else {
-		for d := 0; d < remainingLevels; d++ {
-			buf = append(buf, 0)
-		}
-	}
-	return buf
-}
-
 // ToDot generates a DOT representation for debugging.
 func (s *NodeStore) ToDot(ref NodeRef, parent, path string) string {
 	switch ref.Kind() {

trie/bintrie/trie.go

@@ -107,10 +107,9 @@ func ChunkifyCode(code []byte) ChunkedCode {
 
 // BinaryTrie is the implementation of https://eips.ethereum.org/EIPS/eip-7864.
 type BinaryTrie struct {
-	store      *NodeStore
-	reader     *trie.Reader
-	tracer     *trie.PrevalueTracer
-	groupDepth int
+	store  *NodeStore
+	reader *trie.Reader
+	tracer *trie.PrevalueTracer
 }
 
 // ToDot converts the binary trie to a DOT language representation. Useful for debugging.
@@ -126,10 +125,9 @@ func NewBinaryTrie(root common.Hash, db database.NodeDatabase) (*BinaryTrie, err
 		return nil, err
 	}
 	t := &BinaryTrie{
-		store:      NewNodeStore(),
-		reader:     reader,
-		tracer:     trie.NewPrevalueTracer(),
-		groupDepth: MaxGroupDepth,
+		store:  NewNodeStore(),
+		reader: reader,
+		tracer: trie.NewPrevalueTracer(),
 	}
 	// Parse the root node if it's not empty
 	if root != types.EmptyBinaryHash && root != types.EmptyRootHash {
@@ -311,14 +309,9 @@ func (t *BinaryTrie) Hash() common.Hash {
 func (t *BinaryTrie) Commit(_ bool) (common.Hash, *trienode.NodeSet) {
 	nodeset := trienode.NewNodeSet(common.Hash{})
 
-	groupDepth := t.groupDepth
-	if groupDepth == 0 {
-		groupDepth = MaxGroupDepth
-	}
-
 	err := t.store.CollectNodes(t.store.Root(), nil, func(path []byte, hash common.Hash, serialized []byte) {
 		nodeset.AddNode(path, trienode.NewNodeWithPrev(hash, serialized, t.tracer.Get(path)))
-	}, groupDepth)
+	})
 	if err != nil {
 		panic(fmt.Errorf("CollectNodes failed: %v", err))
 	}
@@ -345,10 +338,9 @@ func (t *BinaryTrie) Prove(key []byte, proofDb ethdb.KeyValueWriter) error {
 // Copy creates a deep copy of the trie.
 func (t *BinaryTrie) Copy() *BinaryTrie {
 	return &BinaryTrie{
-		store:      t.store.Copy(),
-		reader:     t.reader,
-		tracer:     t.tracer.Copy(),
-		groupDepth: t.groupDepth,
+		store:  t.store.Copy(),
+		reader: t.reader,
+		tracer: t.tracer.Copy(),
 	}
 }
 

trie/bintrie/trie_test.go

@@ -190,7 +190,6 @@ func TestStorageRoundTrip(t *testing.T) {
 	tr := &BinaryTrie{
 		store:      NewNodeStore(),
 		tracer:     tracer,
-		groupDepth: MaxGroupDepth,
 	}
 	addr := common.HexToAddress("0x1234567890abcdef1234567890abcdef12345678")
 
@@ -259,7 +258,6 @@ func newEmptyTestTrie(t *testing.T) *BinaryTrie {
 	return &BinaryTrie{
 		store:      NewNodeStore(),
 		tracer:     trie.NewPrevalueTracer(),
-		groupDepth: MaxGroupDepth,
 	}
 }
 
@@ -585,7 +583,6 @@ func TestBinaryTrieWitness(t *testing.T) {
 	tr := &BinaryTrie{
 		store:      NewNodeStore(),
 		tracer:     tracer,
-		groupDepth: MaxGroupDepth,
 	}
 	if w := tr.Witness(); len(w) != 0 {
 		t.Fatal("expected empty witness for fresh trie")
@@ -613,7 +610,6 @@ func testAccount(t *testing.T, addr common.Address, nonce uint64, balance uint64
 	tr := &BinaryTrie{
 		store:      NewNodeStore(),
 		tracer:     trie.NewPrevalueTracer(),
-		groupDepth: MaxGroupDepth,
 	}
 	acc := &types.StateAccount{
 		Nonce:    nonce,
@@ -668,7 +664,6 @@ func TestGetAccountNonMembershipInternalRoot(t *testing.T) {
 	tr := &BinaryTrie{
 		store:      NewNodeStore(),
 		tracer:     trie.NewPrevalueTracer(),
-		groupDepth: MaxGroupDepth,
 	}
 
 	// Insert two accounts whose binary tree keys have different first bits
@@ -732,7 +727,6 @@ func TestGetStorageNonMembershipInternalRoot(t *testing.T) {
 	tr := &BinaryTrie{
 		store:      NewNodeStore(),
 		tracer:     trie.NewPrevalueTracer(),
-		groupDepth: MaxGroupDepth,
 	}
 
 	addr := common.HexToAddress("0x1234567890abcdef1234567890abcdef12345678")