avoid unnecessary get code call when address doesn't have code hash (0…

…xPolygonHermez#3170)

merkletree/tree.go

@@ -93,6 +93,9 @@ func (tree *StateTree) GetCode(ctx context.Context, address common.Address, root
 	}
 
 	k := new(big.Int).SetBytes(scCodeHash)
+	if k.Cmp(big.NewInt(0)) == 0 {
+		return []byte{}, nil
+	}
 
 	// this code gets actual smart contract code from sc code storage
 	scCode, err := tree.getProgram(ctx, scalarToh4(k))

merkletree/tree_test.go

@@ -0,0 +1,86 @@
+package merkletree
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/0xPolygonHermez/zkevm-node/hex"
+	"github.com/0xPolygonHermez/zkevm-node/test/contracts/bin/EmitLog2"
+	"github.com/0xPolygonHermez/zkevm-node/test/testutils"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetCode(t *testing.T) {
+	ctx := context.Background()
+	zkProverURI := testutils.GetEnv("ZKPROVER_URI", "localhost")
+
+	cfg := Config{URI: fmt.Sprintf("%s:50061", zkProverURI)}
+	c, _, _ := NewMTDBServiceClient(ctx, cfg)
+	sTree := NewStateTree(c)
+
+	type testCase struct {
+		name           string
+		addr           common.Address
+		root           []byte
+		expectedResult []byte
+		expectedError  error
+		setup          func(*testing.T, *testCase, *StateTree)
+	}
+
+	testCases := []testCase{
+		{
+			name:           "get existent code successfully",
+			addr:           common.HexToAddress("0x1"),
+			root:           common.HexToHash("0x0").Bytes(),
+			expectedResult: hex.DecodeBig(EmitLog2.EmitLog2Bin).Bytes(),
+			expectedError:  nil,
+			setup: func(t *testing.T, tc *testCase, sTree *StateTree) {
+				txID := uuid.NewString()
+
+				err := sTree.StartBlock(ctx, common.Hash(tc.root), txID)
+				require.NoError(t, err)
+
+				newRoot, _, err := sTree.SetCode(ctx, tc.addr, tc.expectedResult, tc.root, txID)
+				require.NoError(t, err)
+				tc.root = newRoot
+
+				err = sTree.FinishBlock(ctx, common.Hash(tc.root), txID)
+				require.NoError(t, err)
+
+				err = sTree.Flush(ctx, common.Hash(newRoot), txID)
+				require.NoError(t, err)
+			},
+		},
+		{
+			name:           "get non-existent code successfully",
+			addr:           common.HexToAddress("0x2"),
+			root:           common.HexToHash("0x0").Bytes(),
+			expectedResult: []byte{},
+			expectedError:  nil,
+			setup: func(t *testing.T, tc *testCase, sTree *StateTree) {
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			tc := tc
+			tc.setup(t, &tc, sTree)
+
+			result, err := sTree.GetCode(ctx, tc.addr, tc.root)
+			require.NoError(t, err)
+
+			if tc.expectedResult != nil || result != nil {
+				require.Equal(t, len(tc.expectedResult), len(result))
+				require.ElementsMatch(t, tc.expectedResult, result)
+			}
+
+			if tc.expectedError != nil || err != nil {
+				require.Equal(t, tc.expectedError, err)
+			}
+		})
+	}
+}