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, 7 insertions, 4 deletions

diff --git a/trie/trie.go b/trie/trie.go
index cce4cfeb6..30f566a8d 100644
--- a/trie/trie.go
+++ b/trie/trie.go
@@ -144,14 +144,15 @@ func (t *Trie) tryGet(origNode node, key []byte, pos int) (value []byte, newnode
 		if err == nil && didResolve {
 			n = n.copy()
 			n.Val = newnode
+			n.flags.gen = t.cachegen
 		}
 		return value, n, didResolve, err
 	case *fullNode:
 		value, newnode, didResolve, err = t.tryGet(n.Children[key[pos]], key, pos+1)
 		if err == nil && didResolve {
 			n = n.copy()
+			n.flags.gen = t.cachegen
 			n.Children[key[pos]] = newnode
-
 		}
 		return value, n, didResolve, err
 	case hashNode:
@@ -247,7 +248,8 @@ func (t *Trie) insert(n node, prefix, key []byte, value node) (bool, node, error
 			return false, n, err
 		}
 		n = n.copy()
-		n.Children[key[0]], n.flags.hash, n.flags.dirty = nn, nil, true
+		n.flags = t.newFlag()
+		n.Children[key[0]] = nn
 		return true, n, nil
 
 	case nil:
@@ -331,7 +333,8 @@ func (t *Trie) delete(n node, prefix, key []byte) (bool, node, error) {
 			return false, n, err
 		}
 		n = n.copy()
-		n.Children[key[0]], n.flags.hash, n.flags.dirty = nn, nil, true
+		n.flags = t.newFlag()
+		n.Children[key[0]] = nn
 
 		// Check how many non-nil entries are left after deleting and
 		// reduce the full node to a short node if only one entry is
@@ -427,7 +430,7 @@ func (t *Trie) resolveHash(n hashNode, prefix, suffix []byte) (node, error) {
 			SuffixLen: len(suffix),
 		}
 	}
-	dec := mustDecodeNode(n, enc)
+	dec := mustDecodeNode(n, enc, t.cachegen)
 	return dec, nil
 }