fix(trace): deletion proof missed path terminated by empty node (#330)

* fix deletion proof issue on empty node

* refine for better implement and fix unittest

* Update version.go

---------

Co-authored-by: HAOYUatHZ <37070449+HAOYUatHZ@users.noreply.github.com>

params/version.go

@@ -24,7 +24,7 @@ import (
 const (
 	VersionMajor = 3       // Major version component of the current release
 	VersionMinor = 2       // Minor version component of the current release
-	VersionPatch = 2       // Patch version component of the current release
+	VersionPatch = 3       // Patch version component of the current release
 	VersionMeta  = "alpha" // Version metadata to append to the version string
 )
 

trie/zk_trie_proof_test.go

@@ -244,11 +244,12 @@ func TestProofWithDeletion(t *testing.T) {
 	// notice the sibling of key `k*32`` is just the leaf of key `m*32`
 	assert.Equal(t, siblings[0][l-33:l-1], nd)
 
-	// no effect
+	// Marking a key that is currently not hit (but terminated by an empty node)
+	// also causes it to be added to the deletion proof
 	proofTracer.MarkDeletion(s_key2.Bytes())
 	siblings, err = proofTracer.GetDeletionProofs()
 	assert.NoError(t, err)
-	assert.Equal(t, 1, len(siblings))
+	assert.Equal(t, 2, len(siblings))
 
 	key3 := bytes.Repeat([]byte("x"), 32)
 	err = mt.UpdateWord(

trie/zktrie_deletionproof.go

@@ -28,6 +28,7 @@ type ProofTracer struct {
 	*ZkTrie
 	deletionTracer map[zkt.Hash]struct{}
 	rawPaths       map[string][]*zktrie.Node
+	emptyTermPaths map[string][]*zktrie.Node
 }
 
 // NewProofTracer create a proof tracer object
@@ -37,6 +38,7 @@ func (t *ZkTrie) NewProofTracer() *ProofTracer {
 		// always consider 0 is "deleted"
 		deletionTracer: map[zkt.Hash]struct{}{zkt.HashZero: {}},
 		rawPaths:       make(map[string][]*zktrie.Node),
+		emptyTermPaths: make(map[string][]*zktrie.Node),
 	}
 }
 
@@ -112,9 +114,13 @@ func (t *ProofTracer) GetDeletionProofs() ([][]byte, error) {
 
 // MarkDeletion mark a key has been involved into deletion
 func (t *ProofTracer) MarkDeletion(key []byte) {
-	if path, existed := t.rawPaths[string(key)]; existed {
+	if path, existed := t.emptyTermPaths[string(key)]; existed {
+		// copy empty node terminated path for final scanning
+		t.rawPaths[string(key)] = path
+	} else if path, existed = t.rawPaths[string(key)]; existed {
 		// sanity check
 		leafNode := path[len(path)-1]
+
 		if leafNode.Type != zktrie.NodeTypeLeaf {
 			panic("all path recorded in proofTrace should be ended with leafNode")
 		}
@@ -143,6 +149,11 @@ func (t *ProofTracer) Prove(key []byte, fromLevel uint, proofDb ethdb.KeyValueWr
 				}
 			} else if n.Type == zktrie.NodeTypeParent {
 				mptPath = append(mptPath, n)
+			} else if n.Type == zktrie.NodeTypeEmpty {
+				// empty node is considered as "unhit" but it should be also being added
+				// into a temporary slot for possibly being marked as deletion later
+				mptPath = append(mptPath, n)
+				t.emptyTermPaths[string(key)] = mptPath
 			}
 
 			return proofDb.Put(nodeHash[:], n.Value())