trie: ensure resolved nodes stay loaded

Commit 40cdcf1183 broke the optimisation which kept nodes resolved
during Get in the trie. The decoder assigned cache generation 0
unconditionally, causing resolved nodes to get flushed on Commit.

This commit fixes it and adds two tests.

1 files changed, 13 insertions, 13 deletions

diff --git a/trie/node.go b/trie/node.go
index de9752c93..4aa0cab65 100644
--- a/trie/node.go
+++ b/trie/node.go
@@ -104,8 +104,8 @@ func (n valueNode) fstring(ind string) string {
 	return fmt.Sprintf("%x ", []byte(n))
 }
 
-func mustDecodeNode(hash, buf []byte) node {
-	n, err := decodeNode(hash, buf)
+func mustDecodeNode(hash, buf []byte, cachegen uint16) node {
+	n, err := decodeNode(hash, buf, cachegen)
 	if err != nil {
 		panic(fmt.Sprintf("node %x: %v", hash, err))
 	}
@@ -113,7 +113,7 @@ func mustDecodeNode(hash, buf []byte) node {
 }
 
 // decodeNode parses the RLP encoding of a trie node.
-func decodeNode(hash, buf []byte) (node, error) {
+func decodeNode(hash, buf []byte, cachegen uint16) (node, error) {
 	if len(buf) == 0 {
 		return nil, io.ErrUnexpectedEOF
 	}
@@ -123,22 +123,22 @@ func decodeNode(hash, buf []byte) (node, error) {
 	}
 	switch c, _ := rlp.CountValues(elems); c {
 	case 2:
-		n, err := decodeShort(hash, buf, elems)
+		n, err := decodeShort(hash, buf, elems, cachegen)
 		return n, wrapError(err, "short")
 	case 17:
-		n, err := decodeFull(hash, buf, elems)
+		n, err := decodeFull(hash, buf, elems, cachegen)
 		return n, wrapError(err, "full")
 	default:
 		return nil, fmt.Errorf("invalid number of list elements: %v", c)
 	}
 }
 
-func decodeShort(hash, buf, elems []byte) (node, error) {
+func decodeShort(hash, buf, elems []byte, cachegen uint16) (node, error) {
 	kbuf, rest, err := rlp.SplitString(elems)
 	if err != nil {
 		return nil, err
 	}
-	flag := nodeFlag{hash: hash}
+	flag := nodeFlag{hash: hash, gen: cachegen}
 	key := compactDecode(kbuf)
 	if key[len(key)-1] == 16 {
 		// value node
@@ -148,17 +148,17 @@ func decodeShort(hash, buf, elems []byte) (node, error) {
 		}
 		return &shortNode{key, append(valueNode{}, val...), flag}, nil
 	}
-	r, _, err := decodeRef(rest)
+	r, _, err := decodeRef(rest, cachegen)
 	if err != nil {
 		return nil, wrapError(err, "val")
 	}
 	return &shortNode{key, r, flag}, nil
 }
 
-func decodeFull(hash, buf, elems []byte) (*fullNode, error) {
-	n := &fullNode{flags: nodeFlag{hash: hash}}
+func decodeFull(hash, buf, elems []byte, cachegen uint16) (*fullNode, error) {
+	n := &fullNode{flags: nodeFlag{hash: hash, gen: cachegen}}
 	for i := 0; i < 16; i++ {
-		cld, rest, err := decodeRef(elems)
+		cld, rest, err := decodeRef(elems, cachegen)
 		if err != nil {
 			return n, wrapError(err, fmt.Sprintf("[%d]", i))
 		}
@@ -176,7 +176,7 @@ func decodeFull(hash, buf, elems []byte) (*fullNode, error) {
 
 const hashLen = len(common.Hash{})
 
-func decodeRef(buf []byte) (node, []byte, error) {
+func decodeRef(buf []byte, cachegen uint16) (node, []byte, error) {
 	kind, val, rest, err := rlp.Split(buf)
 	if err != nil {
 		return nil, buf, err
@@ -189,7 +189,7 @@ func decodeRef(buf []byte) (node, []byte, error) {
 			err := fmt.Errorf("oversized embedded node (size is %d bytes, want size < %d)", size, hashLen)
 			return nil, buf, err
 		}
-		n, err := decodeNode(nil, buf)
+		n, err := decodeNode(nil, buf, cachegen)
 		return n, rest, err
 	case kind == rlp.String && len(val) == 0:
 		// empty node