@@ -19,7 +19,7 @@ // We use go-bare for export/import the trie. In order to support
 // big census (up to 8 Million entries) we need to increase the maximums.
 const bareMaxArrayLength uint64 = 1024 * 1014 * 8 // 8 Million
 
-const bareMaxUnmarshalBytes uint64 = 1024 * 1024 * 200 // 200 MiB
+const bareMaxUnmarshalBytes uint64 = bareMaxArrayLength * 32 * 2 // 512 MiB
 
 type Tree struct {
 	Tree           *asmt.Trie
@@ -48,8 +48,8 @@ Elements []exportElement `bare:"elements"`
 }
 
 const (
-	MaxKeySize   = 256
-	MaxValueSize = 256
+	MaxKeySize   = 32
+	MaxValueSize = 64
 	dbRootPrefix = "this is the last root for the SMT tree"
 )
 

@@ -8,6 +8,6 @@ github.com/aergoio/aergo-lib v1.0.2
 	github.com/guptarohit/asciigraph v0.4.1
 	github.com/stretchr/testify v1.7.0
 	github.com/syndtr/goleveldb v1.0.1-0.20200815110645-5c35d600f0ca
-	go.vocdoni.io/dvote v1.0.0
+	go.vocdoni.io/dvote v0.6.1-0.20210326182730-ba86106de602
 	golang.org/x/crypto v0.0.0-20210317152858-513c2a44f670
 )

@@ -1547,11 +1547,11 @@ go.vocdoni.io/dvote v0.6.1-0.20210125120603-df82783bb500/go.mod h1:Kf3LwprU/2MhEXLmgL34N12mn3TmhJZ0EnPPL7LoNXs=
 go.vocdoni.io/dvote v0.6.1-0.20210129144810-e6ce68464ed2/go.mod h1:7yTzMiJiZY3E9djQAuEsjEuDhflLcVJKqd1chYC1GVI=
 go.vocdoni.io/dvote v0.6.1-0.20210130094936-75dbb92de3f0/go.mod h1:NJyERGs2LmEvlevZUtOl36MI0HlOUh0d2I0vJcYh5RE=
 go.vocdoni.io/dvote v0.6.1-0.20210206210936-a0407e833753/go.mod h1:HhMMtdnkLI3ujk+zcL1frzFg5S7SbvxWtis7RZTq1dA=
-go.vocdoni.io/dvote v1.0.0 h1:a6sSDmeyLfwBZ9b++2UI+BI9KPLglpp7KRuVOSEDfgo=
-go.vocdoni.io/dvote v1.0.0/go.mod h1:C9wjSWCzy33Bl2sNiF/2ie/oxcERR3uRD2G2c/NDeH0=
+go.vocdoni.io/dvote v0.6.1-0.20210326182730-ba86106de602 h1:qVDdnaU0vaWST5g/pt2P5Pg/gzqTuZfWQFAx7ChD/HQ=
+go.vocdoni.io/dvote v0.6.1-0.20210326182730-ba86106de602/go.mod h1:TXzXfwGzoRhINzmiCtsuVnMya62WclVeFMUcWP29UwY=
 go.vocdoni.io/proto v0.1.7/go.mod h1:cyITrt7+sHmUJH06WLu69xB7LBY9c9FakFaBOe8gs/M=
 go.vocdoni.io/proto v0.1.8/go.mod h1:cyITrt7+sHmUJH06WLu69xB7LBY9c9FakFaBOe8gs/M=
-go.vocdoni.io/proto v0.1.9-0.20210304214308-6f7363b52750/go.mod h1:cyITrt7+sHmUJH06WLu69xB7LBY9c9FakFaBOe8gs/M=
+go.vocdoni.io/proto v1.0.2/go.mod h1:cyITrt7+sHmUJH06WLu69xB7LBY9c9FakFaBOe8gs/M=
 go4.org v0.0.0-20180809161055-417644f6feb5/go.mod h1:MkTOUMDaeVYJUOUsaDXIhWPZYa1yOyC1qaOBpL57BhE=
 go4.org v0.0.0-20200411211856-f5505b9728dd/go.mod h1:CIiUVy99QCPfoE13bO4EZaz5GZMZXMSBGhxRdsvzbkg=
 golang.org/x/arch v0.0.0-20190919213554-7fe50f7625bd/go.mod h1:flIaEI6LNU6xOCD5PaJvn9wGP0agmIOqjrtsKGRguv4=

@@ -137,7 +137,7 @@ } else {
 			// create a new shortcut batch.
 			// simply storing the value will make it hard to move up the
 			// shortcut in case of sibling deletion
-			batch = make([][]byte, 31, 31)
+			batch = make([][]byte, 31)
 			node := s.leafHash(keys[0], values[0], root, batch, 0, height)
 			ch <- mresult{node, false, nil}
 		}
@@ -413,7 +413,7 @@ isShortcut := false
 	if height%4 == 0 {
 		if len(root) == 0 {
 			// create a new default batch
-			batch = make([][]byte, 31, 31)
+			batch = make([][]byte, 31)
 			batch[0] = []byte{0}
 		} else {
 			var err error
@@ -452,7 +452,7 @@ if s.atomicUpdate {
 			// Return a copy so that Commit() doesnt have to be called at
 			// each block and still commit every state transition.
 			// Before Commit, the same batch is in liveCache and in updatedNodes
-			newVal := make([][]byte, 31, 31)
+			newVal := make([][]byte, 31)
 			copy(newVal, val)
 			return newVal, nil
 		}
@@ -466,7 +466,7 @@ if exists {
 		if s.atomicUpdate {
 			// Return a copy so that Commit() doesnt have to be called at
 			// each block and still commit every state transition.
-			newVal := make([][]byte, 31, 31)
+			newVal := make([][]byte, 31)
 			copy(newVal, val)
 			return newVal, nil
 		}
@@ -493,7 +493,7 @@ }
 
 // parseBatch decodes the byte data into a slice of nodes and bitmap
 func (s *Trie) parseBatch(val []byte) [][]byte {
-	batch := make([][]byte, 31, 31)
+	batch := make([][]byte, 31)
 	bitmap := val[:4]
 	// check if the batch root is a shortcut
 	if bitIsSet(val, 31) {

@@ -77,7 +77,9 @@ root, _ := smt.AtomicUpdate(keys, values)
 	updatedNb := len(smt.db.updatedNodes)
 	cacheNb := len(smt.db.liveCache)
 	newvalues := getFreshData(1, 32)
-	smt.AtomicUpdate(keys, newvalues)
+	if _, err := smt.AtomicUpdate(keys, newvalues); err != nil {
+		t.Fatal(err)
+	}
 	if len(smt.db.updatedNodes) != 2*updatedNb {
 		t.Fatal("Atomic update doesnt store all tries")
 	}
@@ -118,7 +120,9 @@ t.Fatal("Root not stored")
 	}
 
 	newValues := getFreshData(20, 32)
-	smt.Update(keys, newValues)
+	if _, err := smt.Update(keys, newValues); err != nil {
+		t.Fatal(err)
+	}
 
 	if len(smt.db.updatedNodes) != updatedNb {
 		t.Fatal("multiple updates don't actualise updated nodes")
@@ -354,9 +358,11 @@ smt = NewTrie(nil, Hasher, nil)
 	keys = getFreshData(2, 32)
 	values = getFreshData(2, 32)
 	root, _ = smt.Update(keys, values)
-	key0 := make([]byte, 32, 32)
-	key1 := make([]byte, 32, 32)
-	smt.Update([][]byte{key0, key1}, [][]byte{DefaultLeaf, DefaultLeaf})
+	key0 := make([]byte, 32)
+	key1 := make([]byte, 32)
+	if _, err := smt.Update([][]byte{key0, key1}, [][]byte{DefaultLeaf, DefaultLeaf}); err != nil {
+		t.Fatal(err)
+	}
 	if !bytes.Equal(root, smt.Root) {
 		t.Fatal("deleting a default key shouldnt' modify the tree")
 	}
@@ -366,7 +372,7 @@ // test updating and deleting at the same time
 func TestTrieUpdateAndDelete(t *testing.T) {
 	smt := NewTrie(nil, Hasher, nil)
 	smt.CacheHeightLimit = 0
-	key0 := make([]byte, 32, 32)
+	key0 := make([]byte, 32)
 	values := getFreshData(1, 32)
 	root, _ := smt.Update([][]byte{key0}, values)
 	cacheNb := len(smt.db.liveCache)
@@ -377,7 +383,7 @@ if !isShortcut || !bytes.Equal(k[:HashLength], key0) || !bytes.Equal(v[:HashLength], values[0]) {
 		t.Fatal("leaf shortcut didn't move up to root")
 	}
 
-	key1 := make([]byte, 32, 32)
+	key1 := make([]byte, 32)
 	// set the last bit
 	bitSet(key1, 255)
 	keys := [][]byte{key0, key1}
@@ -403,7 +409,9 @@ smt := NewTrie(nil, Hasher, nil)
 	// Add data to empty trie
 	keys := getFreshData(10, 32)
 	values := getFreshData(10, 32)
-	smt.Update(keys, values)
+	if _, err := smt.Update(keys, values); err != nil {
+		t.Fatal(err)
+	}
 
 	for i, key := range keys {
 		ap, _, k, v, _ := smt.MerkleProof(key)
@@ -429,7 +437,9 @@ smt := NewTrie(nil, Hasher, nil)
 	// Add data to empty trie
 	keys := getFreshData(10, 32)
 	values := getFreshData(10, 32)
-	smt.Update(keys, values)
+	if _, err := smt.Update(keys, values); err != nil {
+		t.Fatal(err)
+	}
 
 	for i, key := range keys {
 		bitmap, ap, length, _, k, v, _ := smt.MerkleProofCompressed(key)
@@ -460,8 +470,12 @@
 	smt := NewTrie(nil, Hasher, st)
 	keys := getFreshData(10, 32)
 	values := getFreshData(10, 32)
-	smt.Update(keys, values)
-	smt.Commit()
+	if _, err := smt.Update(keys, values); err != nil {
+		t.Fatal(err)
+	}
+	if err := smt.Commit(); err != nil {
+		t.Fatal(err)
+	}
 	// liveCache is deleted so the key is fetched in badger db
 	smt.db.liveCache = make(map[Hash][][]byte)
 	for i, key := range keys {
@@ -484,7 +498,9 @@
 	smt := NewTrie(nil, Hasher, st)
 	keys := getFreshData(10, 32)
 	values := getFreshData(10, 32)
-	smt.Update(keys, values)
+	if _, err := smt.Update(keys, values); err != nil {
+		t.Fatal(err)
+	}
 	txn := st.NewTx()
 	smt.StageUpdates(txn.(DbTx))
 	txn.Commit()
@@ -511,52 +527,75 @@ smt := NewTrie(nil, Hasher, st)
 
 	// Edge case : Test that revert doesnt delete shortcut nodes
 	// when moved to a different position in tree
-	key0 := make([]byte, 32, 32)
-	key1 := make([]byte, 32, 32)
+	key0 := make([]byte, 32)
+	key1 := make([]byte, 32)
 	// setting the bit at 251 creates 2 shortcut batches at height 252
 	bitSet(key1, 251)
 	values := getFreshData(2, 32)
-	keys := [][]byte{key0, key1}
 	root, _ := smt.Update([][]byte{key0}, [][]byte{values[0]})
-	smt.Commit()
+	if err := smt.Commit(); err != nil {
+		t.Fatal(err)
+	}
 	root2, _ := smt.Update([][]byte{key1}, [][]byte{values[1]})
-	smt.Commit()
-	smt.Revert(root)
+	if err := smt.Commit(); err != nil {
+		t.Fatal(err)
+	}
+	if err := smt.Revert(root); err != nil {
+		t.Fatal(err)
+	}
 	if len(smt.db.Store.Get(root)) == 0 {
 		t.Fatal("shortcut node shouldnt be deleted by revert")
 	}
 	if len(smt.db.Store.Get(root2)) != 0 {
 		t.Fatal("reverted root should have been deleted")
 	}
-	key1 = make([]byte, 32, 32)
+	key1 = make([]byte, 32)
 	// setting the bit at 255 stores the keys as the tip
 	bitSet(key1, 255)
-	smt.Update([][]byte{key1}, [][]byte{values[1]})
-	smt.Commit()
-	smt.Revert(root)
+	if _, err := smt.Update([][]byte{key1}, [][]byte{values[1]}); err != nil {
+		t.Fatal(err)
+	}
+	if err := smt.Commit(); err != nil {
+		t.Fatal(err)
+	}
+	if err := smt.Revert(root); err != nil {
+		t.Fatal(err)
+	}
 	if len(smt.db.Store.Get(root)) == 0 {
 		t.Fatal("shortcut node shouldnt be deleted by revert")
 	}
 
 	// Test all nodes are reverted in the usual case
 	// Add data to empty trie
-	keys = getFreshData(10, 32)
+	keys := getFreshData(10, 32)
 	values = getFreshData(10, 32)
 	root, _ = smt.Update(keys, values)
-	smt.Commit()
+	if err := smt.Commit(); err != nil {
+		t.Fatal(err)
+	}
 
 	// Update the values
 	newValues := getFreshData(10, 32)
-	smt.Update(keys, newValues)
+	if _, err := smt.Update(keys, newValues); err != nil {
+		t.Fatal(err)
+	}
 	updatedNodes1 := smt.db.updatedNodes
-	smt.Commit()
+	if err := smt.Commit(); err != nil {
+		t.Fatal(err)
+	}
 	newKeys := getFreshData(10, 32)
 	newValues = getFreshData(10, 32)
-	smt.Update(newKeys, newValues)
+	if _, err := smt.Update(newKeys, newValues); err != nil {
+		t.Fatal(err)
+	}
 	updatedNodes2 := smt.db.updatedNodes
-	smt.Commit()
+	if err := smt.Commit(); err != nil {
+		t.Fatal(err)
+	}
 
-	smt.Revert(root)
+	if err := smt.Revert(root); err != nil {
+		t.Fatal(err)
+	}
 
 	if !bytes.Equal(smt.Root, root) {
 		t.Fatal("revert failed")
@@ -575,12 +614,12 @@ if len(smt.db.liveCache) != 0 {
 		t.Fatal("live cache not reset after revert")
 	}
 	// Check all reverted nodes have been deleted
-	for node, _ := range updatedNodes2 {
+	for node := range updatedNodes2 {
 		if len(smt.db.Store.Get(node[:])) != 0 {
 			t.Fatal("nodes not deleted from database", node)
 		}
 	}
-	for node, _ := range updatedNodes1 {
+	for node := range updatedNodes1 {
 		if len(smt.db.Store.Get(node[:])) != 0 {
 			t.Fatal("nodes not deleted from database", node)
 		}
@@ -600,7 +639,9 @@ smt := NewTrie(nil, Hasher, st)
 	// Add data to empty trie
 	keys := getFreshData(10, 32)
 	values := getFreshData(10, 32)
-	smt.Update(keys, values)
+	if _, err := smt.Update(keys, values); err != nil {
+		t.Fatal(err)
+	}
 	smt.db.liveCache = make(map[Hash][][]byte)
 	smt.db.updatedNodes = make(map[Hash][][]byte)
 
@@ -629,7 +670,7 @@ t.Fatal("Error not created if database not connected")
 	}
 	smt.db.liveCache = make(map[Hash][][]byte)
 	smt.atomicUpdate = false
-	_, _, _, _, _, err = smt.loadChildren(make([]byte, 32, 32), smt.TrieHeight, 0, nil)
+	_, _, _, _, _, err = smt.loadChildren(make([]byte, 32), smt.TrieHeight, 0, nil)
 	if err == nil {
 		t.Fatal("Error not created if database not connected")
 	}
@@ -649,11 +690,13 @@
 	smt := NewTrie(nil, Hasher, st)
 	// Test size of cache
 	smt.CacheHeightLimit = 0
-	key0 := make([]byte, 32, 32)
-	key1 := make([]byte, 32, 32)
+	key0 := make([]byte, 32)
+	key1 := make([]byte, 32)
 	bitSet(key1, 255)
 	values := getFreshData(2, 32)
-	smt.Update([][]byte{key0, key1}, values)
+	if _, err := smt.Update([][]byte{key0, key1}, values); err != nil {
+		t.Fatal(err)
+	}
 	if len(smt.db.liveCache) != 66 {
 		// the nodes are at the tip, so 64 + 2 = 66
 		t.Fatal("cache size incorrect")
@@ -662,8 +705,12 @@
 	// Add data to empty trie
 	keys := getFreshData(10, 32)
 	values = getFreshData(10, 32)
-	smt.Update(keys, values)
-	smt.Commit()
+	if _, err := smt.Update(keys, values); err != nil {
+		t.Fatal(err)
+	}
+	if err := smt.Commit(); err != nil {
+		t.Fatal(err)
+	}
 
 	// Simulate node restart by deleting and loading cache
 	cacheSize := len(smt.db.liveCache)
@@ -685,12 +732,14 @@ func TestHeight0LeafShortcut(t *testing.T) {
 	keySize := 32
 	smt := NewTrie(nil, Hasher, nil)
 	// Add 2 sibling keys that will be stored at height 0
-	key0 := make([]byte, keySize, keySize)
-	key1 := make([]byte, keySize, keySize)
+	key0 := make([]byte, keySize)
+	key1 := make([]byte, keySize)
 	bitSet(key1, keySize*8-1)
 	keys := [][]byte{key0, key1}
 	values := getFreshData(2, 32)
-	smt.Update(keys, values)
+	if _, err := smt.Update(keys, values); err != nil {
+		t.Fatal(err)
+	}
 	updatedNb := len(smt.db.updatedNodes)
 
 	// Check all keys have been stored
@@ -752,13 +801,19 @@ keys := getFreshData(20, 32)
 	values := getFreshData(20, 32)
 	root, _ := smt.Update(keys, values)
 	cacheSize := len(smt.db.liveCache)
-	smt.Commit()
+	if err := smt.Commit(); err != nil {
+		t.Fatal(err)
+	}
 	if len(smt.pastTries) != 1 {
 		t.Fatal("Past tries not updated after commit")
 	}
 	values = getFreshData(20, 32)
-	smt.Update(keys, values)
-	smt.Stash(true)
+	if _, err := smt.Update(keys, values); err != nil {
+		t.Fatal(err)
+	}
+	if err := smt.Stash(true); err != nil {
+		t.Fatal(err)
+	}
 	if len(smt.pastTries) != 1 {
 		t.Fatal("Past tries not updated after commit")
 	}
@@ -773,13 +828,19 @@ t.Fatal("Trie not rolled back")
 	}
 	keys = getFreshData(20, 32)
 	values = getFreshData(20, 32)
-	smt.AtomicUpdate(keys, values)
+	if _, err := smt.AtomicUpdate(keys, values); err != nil {
+		t.Fatal(err)
+	}
 	values = getFreshData(20, 32)
-	smt.AtomicUpdate(keys, values)
+	if _, err := smt.AtomicUpdate(keys, values); err != nil {
+		t.Fatal(err)
+	}
 	if len(smt.pastTries) != 3 {
 		t.Fatal("Past tries not updated after commit")
 	}
-	smt.Stash(true)
+	if err := smt.Stash(true); err != nil {
+		t.Fatal(err)
+	}
 	if !bytes.Equal(smt.Root, root) {
 		t.Fatal("Trie not rolled back")
 	}
@@ -800,15 +861,21 @@ func benchmark10MAccounts10Ktps(smt *Trie, b *testing.B) {
 	//b.ReportAllocs()
 	keys := getFreshData(100, 32)
 	values := getFreshData(100, 32)
-	smt.Update(keys, values)
+	if _, err := smt.Update(keys, values); err != nil {
+		b.Fatal(err)
+	}
 	fmt.Println("\nLoading b.N x 1000 accounts")
 	for i := 0; i < b.N; i++ {
 		newkeys := getFreshData(1000, 32)
 		newvalues := getFreshData(1000, 32)
 		start := time.Now()
-		smt.Update(newkeys, newvalues)
+		if _, err := smt.Update(newkeys, newvalues); err != nil {
+			b.Fatal(err)
+		}
 		end := time.Now()
-		smt.Commit()
+		if err := smt.Commit(); err != nil {
+			b.Fatal(err)
+		}
 		end2 := time.Now()
 		for j, key := range newkeys {
 			val, _ := smt.Get(key)

@@ -201,10 +201,7 @@ func (s *Trie) TrieRootExists(root []byte) bool {
 	s.db.lock.RLock()
 	dbval := s.db.Store.Get(root)
 	s.db.lock.RUnlock()
-	if len(dbval) != 0 {
-		return true
-	}
-	return false
+	return len(dbval) != 0
 }
 
 // Commit stores the updated nodes to disk.