Add lint checks: gofmt, goimports, golint

- gofmt - Gofmt checks whether code was gofmt-ed. By default this tool runs
  with -s option to check for code simplification
- goimports - Goimports does everything that gofmt does. Additionally it checks
  unused imports
- golint - Golint differs from gofmt. Gofmt reformats Go source code, whereas
  golint prints out style mistakes
    - checks the uncommented exported functions & types

Update the code to fix the lint checks.

.github/workflows/lint.yml

@@ -13,4 +13,4 @@ jobs:
       - name: Lint
         run: |
           curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(go env GOPATH)/bin v1.30.0
-          $(go env GOPATH)/bin/golangci-lint run --timeout=5m -E whitespace -E gosec -E gci -E misspell -E gomnd --max-same-issues 0
+          $(go env GOPATH)/bin/golangci-lint run --timeout=5m -E whitespace -E gosec -E gci -E misspell -E gomnd -E gofmt -E goimports -E golint --exclude-use-default=false --max-same-issues 0

common/account.go

@@ -13,6 +13,7 @@ import (
 )
 
 const (
+	// NLEAFELEMS is the number of elements for a leaf
 	NLEAFELEMS = 4
 	// maxNonceValue is the maximum value that the Account.Nonce can have (40 bits: maxNonceValue=2**40-1)
 	maxNonceValue = 0xffffffffff

common/exittree.go

@@ -6,6 +6,7 @@ import (
 	"github.com/iden3/go-merkletree"
 )
 
+// ExitInfo represents the ExitTree Leaf data
 type ExitInfo struct {
 	AccountIdx  Idx
 	MerkleProof *merkletree.CircomVerifierProof

common/fee.go

@@ -4,8 +4,9 @@ package common
 // to incentivaise the materialization of it
 type Fee float64
 
-// RecommendedFee is the recommended fee to pay in USD per transaction set by the coordinator
-// according to the tx type (if the tx requires to create an account and register, only register or he account already esists)
+// RecommendedFee is the recommended fee to pay in USD per transaction set by
+// the coordinator according to the tx type (if the tx requires to create an
+// account and register, only register or he account already esists)
 type RecommendedFee struct {
 	ExistingAccount           float64
 	CreatesAccount            float64
@@ -15,7 +16,9 @@ type RecommendedFee struct {
 // FeeSelector is used to select a percentage from the FeePlan.
 type FeeSelector uint8
 
+// MAXFEEPLAN is the maximum value of the FeePlan
 const MAXFEEPLAN = 256
 
-// FeePlan represents the fee model, a position in the array indicates the percentage of tokens paid in concept of fee for a transaction
+// FeePlan represents the fee model, a position in the array indicates the
+// percentage of tokens paid in concept of fee for a transaction
 var FeePlan = [MAXFEEPLAN]float64{}

common/l1tx.go

@@ -25,6 +25,7 @@ type L1Tx struct {
 	Type            TxType             `meddler:"tx_type"`
 }
 
+// Tx returns a *Tx from the L1Tx
 func (tx *L1Tx) Tx() *Tx {
 	return &Tx{
 		TxID:    tx.TxID,

common/l2tx.go

@@ -18,6 +18,7 @@ type L2Tx struct {
 	Type     TxType      `meddler:"tx_type"`
 }
 
+// Tx returns a *Tx from the L2Tx
 func (tx *L2Tx) Tx() *Tx {
 	return &Tx{
 		TxID:    tx.TxID,

common/pooll2tx.go

@@ -172,6 +172,7 @@ func (tx *PoolL2Tx) VerifySignature(pk *babyjub.PublicKey) bool {
 	return pk.VerifyPoseidon(h, tx.Signature)
 }
 
+// L2Tx returns a *L2Tx from the PoolL2Tx
 func (tx *PoolL2Tx) L2Tx() *L2Tx {
 	return &L2Tx{
 		TxID:     tx.TxID,
@@ -185,6 +186,7 @@ func (tx *PoolL2Tx) L2Tx() *L2Tx {
 	}
 }
 
+// Tx returns a *Tx from the PoolL2Tx
 func (tx *PoolL2Tx) Tx() *Tx {
 	return &Tx{
 		TxID:    tx.TxID,
@@ -197,6 +199,7 @@ func (tx *PoolL2Tx) Tx() *Tx {
 	}
 }
 
+// PoolL2TxsToL2Txs returns an array of []*L2Tx from an array of []*PoolL2Tx
 func PoolL2TxsToL2Txs(txs []*PoolL2Tx) []*L2Tx {
 	var r []*L2Tx
 	for _, tx := range txs {

common/scvars.go

@@ -6,6 +6,7 @@ import (
 	eth "github.com/ethereum/go-ethereum/common"
 )
 
+// RollupVars contain the Rollup smart contract variables
 type RollupVars struct {
 	EthBlockNum    uint64
 	ForgeL1Timeout *big.Int
@@ -15,6 +16,7 @@ type RollupVars struct {
 	Governance     eth.Address
 }
 
+// AuctionVars contain the Auction smart contract variables
 type AuctionVars struct {
 	EthBlockNum       uint64
 	SlotDeadline      uint
@@ -28,8 +30,10 @@ type AuctionVars struct {
 	AllocationRatio   AllocationRatio
 }
 
+// MinBidSlots TODO
 type MinBidSlots [6]uint
 
+// AllocationRatio TODO
 type AllocationRatio struct {
 	Donation uint
 	Burn     uint

common/zk.go

@@ -4,6 +4,8 @@ import (
 	"math/big"
 )
 
+// ZKInputs represents the inputs that will be used to generate the zkSNARK
+// proof
 type ZKInputs struct {
 	InitialIdx    uint64
 	OldStRoot     Hash
@@ -19,7 +21,7 @@ type ZKInputs struct {
 	TxData        []*big.Int
 
 	FromIdx     []uint64
-	ToIdX       []uint64
+	ToIdX       []uint64 //nolint:golint
 	ToAx        []*big.Int
 	ToAy        []*big.Int
 	ToEthAddr   []*big.Int
@@ -55,10 +57,7 @@ type ZKInputs struct {
 	OldValue2 []*big.Int
 }
 
+// CallDataForge TBD
 type CallDataForge struct {
 	// TBD
 }
-
-type ExitTreeLeaf struct {
-	// TBD
-}

coordinator/batch.go

@@ -4,8 +4,8 @@ import (
 	"github.com/hermeznetwork/hermez-node/common"
 )
 
+// Proof TBD this type will be got from the proof server
 type Proof struct {
-	// TBD this type will be got from the proof server
 }
 
 // BatchInfo contans the Batch information
@@ -58,6 +58,7 @@ type BatchQueue struct {
 	queue []*BatchInfo
 }
 
+// NewBatchQueue returns a new *BatchQueue
 func NewBatchQueue() *BatchQueue {
 	return &BatchQueue{
 		queue: []*BatchInfo{},

coordinator/coordinator.go

@@ -14,8 +14,8 @@ import (
 	"github.com/iden3/go-merkletree/db/memory"
 )
 
-// CoordinatorConfig contains the Coordinator configuration
-type CoordinatorConfig struct {
+// Config contains the Coordinator configuration
+type Config struct {
 	ForgerAddress ethCommon.Address
 	LoopInterval  time.Duration
 }
@@ -29,7 +29,7 @@ type Coordinator struct {
 	forging    bool
 	isForgeSeq bool // WIP just for testing while implementing
 
-	config CoordinatorConfig
+	config Config
 
 	batchNum        common.BatchNum
 	batchQueue      *BatchQueue
@@ -45,7 +45,7 @@ type Coordinator struct {
 }
 
 // NewCoordinator creates a new Coordinator
-func NewCoordinator(conf CoordinatorConfig,
+func NewCoordinator(conf Config,
 	hdb *historydb.HistoryDB,
 	txsel *txselector.TxSelector,
 	bb *batchbuilder.BatchBuilder,
@@ -61,6 +61,7 @@ func NewCoordinator(conf CoordinatorConfig,
 	return &c
 }
 
+// Stop stops the Coordinator
 func (c *Coordinator) Stop() {
 	log.Info("Stopping Coordinator")
 	c.stopch <- true

coordinator/coordinator_test.go

@@ -46,7 +46,7 @@ func newTestModules(t *testing.T) (*txselector.TxSelector, *batchbuilder.BatchBu
 func TestCoordinator(t *testing.T) {
 	txsel, bb := newTestModules(t)
 
-	conf := CoordinatorConfig{
+	conf := Config{
 		LoopInterval: 100 * time.Millisecond,
 	}
 	hdb := &historydb.HistoryDB{}

coordinator/proofpool.go

@@ -2,23 +2,29 @@ package coordinator
 
 import "github.com/hermeznetwork/hermez-node/common"
 
+// ServerProofInfo contains the data related to a ServerProof
 type ServerProofInfo struct {
 	// TODO
 	Available bool
 }
 
+// CalculateProof sends the *common.ZKInputs to the ServerProof to compute the
+// Proof
 func (p *ServerProofInfo) CalculateProof(zkInputs *common.ZKInputs) error {
 	return nil
 }
 
+// GetProof retreives the Proof from the ServerProof
 func (p *ServerProofInfo) GetProof() (*Proof, error) {
 	return nil, nil
 }
 
+// ServerProofPool contains the multiple ServerProofInfo
 type ServerProofPool struct {
 	// pool []ServerProofInfo
 }
 
+// GetNextAvailable returns the available ServerProofInfo
 func (p *ServerProofPool) GetNextAvailable() (*ServerProofInfo, error) {
 	return nil, nil
 }

db/statedb/statedb.go

@@ -13,10 +13,12 @@ import (
 	"github.com/iden3/go-merkletree/db/pebble"
 )
 
-// ErrStateDBWithoutMT is used when a method that requires a MerkleTree is called in a StateDB that does not have a MerkleTree defined
+// ErrStateDBWithoutMT is used when a method that requires a MerkleTree is
+// called in a StateDB that does not have a MerkleTree defined
 var ErrStateDBWithoutMT = errors.New("Can not call method to use MerkleTree in a StateDB without MerkleTree")
 
-// ErrAccountAlreadyExists is used when CreateAccount is called and the Account already exists
+// ErrAccountAlreadyExists is used when CreateAccount is called and the Account
+// already exists
 var ErrAccountAlreadyExists = errors.New("Can not CreateAccount because Account already exists")
 
 // KEYCURRENTBATCH is used as key in the db to store the current BatchNum
@@ -24,7 +26,13 @@ var KEYCURRENTBATCH = []byte("currentbatch")
 
 // PATHSTATEDB defines the subpath of the StateDB
 const PATHSTATEDB = "/statedb"
+
+// PATHBATCHNUM defines the subpath of the Batch Checkpoint in the subpath of
+// the StateDB
 const PATHBATCHNUM = "/BatchNum"
+
+// PATHCURRENT defines the subpath of the current Batch in the subpath of the
+// StateDB
 const PATHCURRENT = "/current"
 
 // StateDB represents the StateDB object
@@ -159,7 +167,7 @@ func (s *StateDB) Reset(batchNum common.BatchNum) error {
 		return err
 	}
 	// copy 'BatchNumX' to 'current'
-	cmd := exec.Command("cp", "-r", checkpointPath, currentPath)
+	cmd := exec.Command("cp", "-r", checkpointPath, currentPath) //nolint:gosec
 	err = cmd.Run()
 	if err != nil {
 		return err
@@ -354,13 +362,13 @@ func (l *LocalStateDB) Reset(batchNum common.BatchNum, fromSynchronizer bool) er
 			return err
 		}
 		// copy synchronizer'BatchNumX' to 'current'
-		cmd := exec.Command("cp", "-r", synchronizerCheckpointPath, currentPath)
+		cmd := exec.Command("cp", "-r", synchronizerCheckpointPath, currentPath) //nolint:gosec
 		err = cmd.Run()
 		if err != nil {
 			return err
 		}
 		// copy synchronizer-'BatchNumX' to 'BatchNumX'
-		cmd = exec.Command("cp", "-r", synchronizerCheckpointPath, checkpointPath)
+		cmd = exec.Command("cp", "-r", synchronizerCheckpointPath, checkpointPath) //nolint:gosec
 		err = cmd.Run()
 		if err != nil {
 			return err

eth/client.go

@@ -17,10 +17,11 @@ import (
 )
 
 var (
+	// ErrAccountNil is used when the calls can not be made because the account is nil
 	ErrAccountNil = fmt.Errorf("Authorized calls can't be made when the account is nil")
-	// ErrReceiptStatusFailed when receiving a failed transaction
+	// ErrReceiptStatusFailed is used when receiving a failed transaction
 	ErrReceiptStatusFailed = fmt.Errorf("receipt status is failed")
-	// ErrReceiptNotRecieved when unable to retrieve a transaction
+	// ErrReceiptNotReceived is used when unable to retrieve a transaction
 	ErrReceiptNotReceived = fmt.Errorf("receipt not available")
 )
 
@@ -36,6 +37,7 @@ const (
 	defaultIntervalReceiptLoop = 200
 )
 
+// Config defines the configuration parameters of the Client
 type Config struct {
 	CallGasLimit        uint64
 	DeployGasLimit      uint64
@@ -115,6 +117,7 @@ func (c *Client) CallAuth(gasLimit uint64,
 	return tx, err
 }
 
+// ContractData contains the contract data
 type ContractData struct {
 	Address ethCommon.Address
 	Tx      *types.Transaction
@@ -161,7 +164,7 @@ func (c *Client) Call(fn func(*ethclient.Client) error) error {
 // WaitReceipt will block until a transaction is confirmed.  Internally it
 // polls the state every 200 milliseconds.
 func (c *Client) WaitReceipt(tx *types.Transaction) (*types.Receipt, error) {
-	return c.waitReceipt(tx, context.TODO(), c.ReceiptTimeout)
+	return c.waitReceipt(context.TODO(), tx, c.ReceiptTimeout)
 }
 
 // GetReceipt will check if a transaction is confirmed and return
@@ -170,10 +173,10 @@ func (c *Client) WaitReceipt(tx *types.Transaction) (*types.Receipt, error) {
 func (c *Client) GetReceipt(tx *types.Transaction) (*types.Receipt, error) {
 	ctx, cancel := context.WithTimeout(context.TODO(), 1*time.Second)
 	defer cancel()
-	return c.waitReceipt(tx, ctx, 0)
+	return c.waitReceipt(ctx, tx, 0)
 }
 
-func (c *Client) waitReceipt(tx *types.Transaction, ctx context.Context, timeout time.Duration) (*types.Receipt, error) {
+func (c *Client) waitReceipt(ctx context.Context, tx *types.Transaction, timeout time.Duration) (*types.Receipt, error) {
 	var err error
 	var receipt *types.Receipt
 
@@ -233,6 +236,7 @@ func (c *Client) BlockByNumber(ctx context.Context, number *big.Int) (*common.Bl
 	return b, nil
 }
 
+// ForgeCall send the *common.CallDataForge to the Forge method of the smart contract
 func (c *Client) ForgeCall(callData *common.CallDataForge) ([]byte, error) {
 	// TODO this depends on the smart contracts, once are ready this will be updated
 	return nil, nil

log/log.go

@@ -62,7 +62,7 @@ func Init(levelStr, errorsPath string) {
 
 	if errorsPath != "" {
 		log.Infof("file where errors will be written: %s", errorsPath)
-		errorsFile, err = os.OpenFile(errorsPath, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
+		errorsFile, err = os.OpenFile(errorsPath, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644) //nolint:gosec
 		if err != nil {
 			panic(err)
 		}
@@ -76,7 +76,7 @@ func writeToErrorsFile(msg string) {
 		return
 	}
 	//nolint:errcheck
-	errorsFile.WriteString(fmt.Sprintf("%s %s\n", time.Now().Format(time.RFC3339), msg))
+	errorsFile.WriteString(fmt.Sprintf("%s %s\n", time.Now().Format(time.RFC3339), msg)) //nolint:gosec
 }
 
 // Debug calls log.Debug

test/lang.go

@@ -13,10 +13,14 @@ import (
 
 var eof = rune(0)
 var errof = fmt.Errorf("eof in parseline")
-var ecomment = fmt.Errorf("comment in parseline")
-var enewbatch = fmt.Errorf("newbatch")
+var errComment = fmt.Errorf("comment in parseline")
+var errNewBatch = fmt.Errorf("newbatch")
+
+// TypeNewBatch is used for testing purposes only, and represents the
+// common.TxType of a new batch
 var TypeNewBatch common.TxType = "TxTypeNewBatch"
 
+//nolint
 const (
 	ILLEGAL token = iota
 	WS
@@ -25,6 +29,7 @@ const (
 	IDENT // val
 )
 
+// Instruction is the data structure that represents one line of code
 type Instruction struct {
 	Literal string
 	From    string
@@ -35,6 +40,7 @@ type Instruction struct {
 	Type    common.TxType // D: Deposit, T: Transfer, E: ForceExit
 }
 
+// Instructions contains the full Set of Instructions representing a full code
 type Instructions struct {
 	Instructions []*Instruction
 	Accounts     []string
@@ -64,6 +70,7 @@ func (i Instruction) String() string {
 	return buf.String()
 }
 
+// Raw returns a string with the raw representation of the Instruction
 func (i Instruction) Raw() string {
 	buf := bytes.NewBufferString("")
 	fmt.Fprintf(buf, "%s", i.From)
@@ -104,8 +111,8 @@ func isDigit(ch rune) bool {
 	return (ch >= '0' && ch <= '9')
 }
 
-// NewScanner creates a new scanner with the given io.Reader
-func NewScanner(r io.Reader) *scanner {
+// newScanner creates a new scanner with the given io.Reader
+func newScanner(r io.Reader) *scanner {
 	return &scanner{r: bufio.NewReader(r)}
 }
 
@@ -196,7 +203,7 @@ type Parser struct {
 
 // NewParser creates a new parser from a io.Reader
 func NewParser(r io.Reader) *Parser {
-	return &Parser{s: NewScanner(r)}
+	return &Parser{s: newScanner(r)}
 }
 
 func (p *Parser) scan() (tok token, lit string) {
@@ -239,10 +246,10 @@ func (p *Parser) parseLine() (*Instruction, error) {
 	c.Literal += lit
 	if lit == "/" {
 		_, _ = p.s.r.ReadString('\n')
-		return nil, ecomment
+		return nil, errComment
 	} else if lit == ">" {
 		_, _ = p.s.r.ReadString('\n')
-		return nil, enewbatch
+		return nil, errNewBatch
 	}
 	c.From = lit
 
@@ -342,11 +349,11 @@ func (p *Parser) Parse() (Instructions, error) {
 		if err == errof {
 			break
 		}
-		if err == ecomment {
+		if err == errComment {
 			i++
 			continue
 		}
-		if err == enewbatch {
+		if err == errNewBatch {
 			i++
 			inst := &Instruction{Type: TypeNewBatch}
 			instructions.Instructions = append(instructions.Instructions, inst)

test/sets.go

@@ -15,7 +15,7 @@ package test
 // 	> and here the comment
 // 	move one batch forward
 
-// Set0 has 3 batches, 29 different accounts, with:
+// SetTest0 has 3 batches, 29 different accounts, with:
 // - 3 TokenIDs
 // - 29+5+10 L1 txs (deposits & exits)
 // - 21+53+7 L2 transactions

test/txs.go

@@ -15,6 +15,7 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+// Account contains the data related to a testing account
 type Account struct {
 	BJJ   *babyjub.PrivateKey
 	Addr  ethCommon.Address
@@ -151,6 +152,8 @@ func GenerateTestTxs(t *testing.T, instructions Instructions) ([][]*common.L1Tx,
 	return l1Txs, coordinatorL1Txs, poolL2Txs
 }
 
+// GenerateTestTxsFromSet reurns the L1 & L2 transactions for a given Set of
+// Instructions code
 func GenerateTestTxsFromSet(t *testing.T, set string) ([][]*common.L1Tx, [][]*common.L1Tx, [][]*common.PoolL2Tx) {
 	parser := NewParser(strings.NewReader(set))
 	instructions, err := parser.Parse()

utils/utils.go

@@ -1,3 +1,7 @@
+// Package utils provides methods to work with Hermez custom half float
+// precision, 16 bits, codification internally called Float16 has been adopted
+// to encode large integers. This is done in order to save bits when L2
+// transactions are published.
 //nolint:gomnd
 package utils
 
@@ -23,8 +27,8 @@ func (f16 Float16) Bytes() []byte {
 }
 
 // BigInt converts the Float16 to a *big.Int integer
-func (fl16 *Float16) BigInt() *big.Int {
-	fl := int64(*fl16)
+func (f16 *Float16) BigInt() *big.Int {
+	fl := int64(*f16)
 
 	m := big.NewInt(fl & 0x3FF)
 	e := big.NewInt(fl >> 11)

utils/utils_test.go

@@ -101,17 +101,17 @@ func BenchmarkFloat16(b *testing.B) {
 		BigInt  *big.Int
 	}
 	testVector := []pair{
-		pair{0x307B, newBigInt("123000000")},
-		pair{0x1DC6, newBigInt("454500")},
-		pair{0xFFFF, newBigInt("10235000000000000000000000000000000")},
-		pair{0x0000, newBigInt("0")},
-		pair{0x0400, newBigInt("0")},
-		pair{0x0001, newBigInt("1")},
-		pair{0x0401, newBigInt("1")},
-		pair{0x0800, newBigInt("0")},
-		pair{0x0c00, newBigInt("5")},
-		pair{0x0801, newBigInt("10")},
-		pair{0x0c01, newBigInt("15")},
+		{0x307B, newBigInt("123000000")},
+		{0x1DC6, newBigInt("454500")},
+		{0xFFFF, newBigInt("10235000000000000000000000000000000")},
+		{0x0000, newBigInt("0")},
+		{0x0400, newBigInt("0")},
+		{0x0001, newBigInt("1")},
+		{0x0401, newBigInt("1")},
+		{0x0800, newBigInt("0")},
+		{0x0c00, newBigInt("5")},
+		{0x0801, newBigInt("10")},
+		{0x0c01, newBigInt("15")},
 	}
 	b.Run("floorFix2Float()", func(b *testing.B) {
 		for i := 0; i < b.N; i++ {
@@ -120,7 +120,7 @@ func BenchmarkFloat16(b *testing.B) {
 	})
 	b.Run("NewFloat16()", func(b *testing.B) {
 		for i := 0; i < b.N; i++ {
-			NewFloat16(testVector[i%len(testVector)].BigInt) //nolint:errcheck
+			_, _ = NewFloat16(testVector[i%len(testVector)].BigInt)
 		}
 	})
 	b.Run("Float16.BigInt()", func(b *testing.B) {