Add golangci-lint to GHA & fix lint warnings

.github/workflows/lint.yml

@@ -0,0 +1,16 @@
+name: Lint
+on: [ push, pull_request ]
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@v1
+        with:
+          go-version: 1.14.x
+      - name: Checkout code
+        uses: actions/checkout@v2
+      - 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

db/leveldb/leveldb.go

@@ -3,13 +3,12 @@ package leveldb
 import (
 	"encoding/json"
 
+	"github.com/iden3/go-merkletree/db"
 	log "github.com/sirupsen/logrus"
 	"github.com/syndtr/goleveldb/leveldb"
 	"github.com/syndtr/goleveldb/leveldb/errors"
 	"github.com/syndtr/goleveldb/leveldb/opt"
 	"github.com/syndtr/goleveldb/leveldb/util"
-
-	"github.com/iden3/go-merkletree/db"
 )
 
 // LevelDbStorage implements the db.Storage interface

db/memory/memory.go

@@ -57,7 +57,6 @@ func (m *MemoryStorage) Iterate(f func([]byte, []byte) (bool, error)) error {
 		}
 		localkey := v.K[len(m.prefix):]
 		kvs = append(kvs, db.KV{K: localkey, V: v.V})
-
 	}
 	sort.SliceStable(kvs, func(i, j int) bool { return bytes.Compare(kvs[i].K, kvs[j].K) < 0 })
 
@@ -73,7 +72,6 @@ func (m *MemoryStorage) Iterate(f func([]byte, []byte) (bool, error)) error {
 
 // Get implements the method Get of the interface db.Tx
 func (tx *MemoryStorageTx) Get(key []byte) ([]byte, error) {
-
 	if v, ok := tx.kv.Get(db.Concat(tx.s.prefix, key)); ok {
 		return v, nil
 	}

db/pebble/pebble.go

@@ -154,7 +154,7 @@ func (tx *PebbleStorageTx) Add(atx db.Tx) {
 func (tx *PebbleStorageTx) Commit() error {
 	batch := tx.PebbleStorage.pdb.NewBatch()
 	for _, v := range tx.cache {
-		batch.Set(v.K, v.V, nil)
+		_ = batch.Set(v.K, v.V, nil)
 	}
 
 	tx.cache = nil

db/test/test.go

@@ -1,3 +1,4 @@
+//nolint:gomnd
 package test
 
 import (
@@ -108,17 +109,17 @@ func TestIterate(t *testing.T, sto db.Storage) {
 	err = sto1.Iterate(lister)
 	assert.Nil(t, err)
 	assert.Equal(t, 3, len(r))
-	assert.Equal(t, db.KV{[]byte{1}, []byte{4}}, r[0])
-	assert.Equal(t, db.KV{[]byte{2}, []byte{5}}, r[1])
-	assert.Equal(t, db.KV{[]byte{3}, []byte{6}}, r[2])
+	assert.Equal(t, db.KV{K: []byte{1}, V: []byte{4}}, r[0])
+	assert.Equal(t, db.KV{K: []byte{2}, V: []byte{5}}, r[1])
+	assert.Equal(t, db.KV{K: []byte{3}, V: []byte{6}}, r[2])
 
 	r = []db.KV{}
 	err = sto2.Iterate(lister)
 	assert.Nil(t, err)
 	assert.Equal(t, 3, len(r))
-	assert.Equal(t, db.KV{[]byte{1}, []byte{7}}, r[0])
-	assert.Equal(t, db.KV{[]byte{2}, []byte{8}}, r[1])
-	assert.Equal(t, db.KV{[]byte{3}, []byte{9}}, r[2])
+	assert.Equal(t, db.KV{K: []byte{1}, V: []byte{7}}, r[0])
+	assert.Equal(t, db.KV{K: []byte{2}, V: []byte{8}}, r[1])
+	assert.Equal(t, db.KV{K: []byte{3}, V: []byte{9}}, r[2])
 }
 
 // TestConcatTx checks that the implementation of the db.Storage interface
@@ -180,13 +181,13 @@ func TestList(t *testing.T, sto db.Storage) {
 	r, err := sto1.List(100)
 	assert.Nil(t, err)
 	assert.Equal(t, 3, len(r))
-	assert.Equal(t, r[0], db.KV{[]byte{1}, []byte{4}})
-	assert.Equal(t, r[1], db.KV{[]byte{2}, []byte{5}})
-	assert.Equal(t, r[2], db.KV{[]byte{3}, []byte{6}})
+	assert.Equal(t, r[0], db.KV{K: []byte{1}, V: []byte{4}})
+	assert.Equal(t, r[1], db.KV{K: []byte{2}, V: []byte{5}})
+	assert.Equal(t, r[2], db.KV{K: []byte{3}, V: []byte{6}})
 
 	r, err = sto1.List(2)
 	assert.Nil(t, err)
 	assert.Equal(t, 2, len(r))
-	assert.Equal(t, r[0], db.KV{[]byte{1}, []byte{4}})
-	assert.Equal(t, r[1], db.KV{[]byte{2}, []byte{5}})
+	assert.Equal(t, r[0], db.KV{K: []byte{1}, V: []byte{4}})
+	assert.Equal(t, r[1], db.KV{K: []byte{2}, V: []byte{5}})
 }

merkletree.go

@@ -20,6 +20,8 @@ const (
 	proofFlagsLen = 2
 	// ElemBytesLen is the length of the Hash byte array
 	ElemBytesLen = 32
+
+	numCharPrint = 8
 )
 
 var (
@@ -60,10 +62,10 @@ type Hash [32]byte
 // String returns decimal representation in string format of the Hash
 func (h Hash) String() string {
 	s := h.BigInt().String()
-	if len(s) < 8 {
+	if len(s) < numCharPrint {
 		return s
 	}
-	return s[0:8] + "..."
+	return s[0:numCharPrint] + "..."
 }
 
 // Hex returns the hexadecimal representation of the Hash
@@ -93,10 +95,10 @@ func (h *Hash) Bytes() []byte {
 // from a byte array that previously has ben generated by the Hash.Bytes()
 // method.
 func NewBigIntFromBytes(b []byte) (*big.Int, error) {
-	if len(b) != 32 {
+	if len(b) != ElemBytesLen {
 		return nil, fmt.Errorf("Expected 32 bytes, found %d bytes", len(b))
 	}
-	return new(big.Int).SetBytes(common.SwapEndianness(b[:32])), nil
+	return new(big.Int).SetBytes(common.SwapEndianness(b[:ElemBytesLen])), nil
 }
 
 // NewHashFromBigInt returns a *Hash representation of the given *big.Int
@@ -110,7 +112,7 @@ func NewHashFromBigInt(b *big.Int) *Hash {
 // in the process. This is the intended method to get a *Hash from a byte array
 // that previously has ben generated by the Hash.Bytes() method.
 func NewHashFromBytes(b []byte) (*Hash, error) {
-	if len(b) != 32 {
+	if len(b) != ElemBytesLen {
 		return nil, fmt.Errorf("Expected 32 bytes, found %d bytes", len(b))
 	}
 	var h Hash
@@ -224,7 +226,7 @@ func (mt *MerkleTree) AddAndGetCircomProof(k, v *big.Int) (*CircomProcessorProof
 	var cp CircomProcessorProof
 	cp.Fnc = 2
 	cp.OldRoot = mt.rootKey
-	gettedK, gettedV, siblings, err := mt.Get(k)
+	gettedK, gettedV, _, err := mt.Get(k)
 	if err != nil && err != ErrKeyNotFound {
 		return nil, err
 	}
@@ -233,7 +235,7 @@ func (mt *MerkleTree) AddAndGetCircomProof(k, v *big.Int) (*CircomProcessorProof
 	if bytes.Equal(cp.OldKey[:], HashZero[:]) {
 		cp.IsOld0 = true
 	}
-	_, _, siblings, err = mt.Get(k)
+	_, _, siblings, err := mt.Get(k)
 	if err != nil && err != ErrKeyNotFound {
 		return nil, err
 	}
@@ -583,12 +585,12 @@ func (mt *MerkleTree) rmAndUpload(tx db.Tx, path []bool, kHash *Hash, siblings [
 	}
 
 	toUpload := siblings[len(siblings)-1]
-	if len(siblings) < 2 {
+	if len(siblings) < 2 { //nolint:gomnd
 		mt.rootKey = siblings[0]
 		mt.dbInsert(tx, rootNodeValue, DBEntryTypeRoot, mt.rootKey[:])
 		return tx.Commit()
 	}
-	for i := len(siblings) - 2; i >= 0; i-- {
+	for i := len(siblings) - 2; i >= 0; i-- { //nolint:gomnd
 		if !bytes.Equal(siblings[i][:], HashZero[:]) {
 			var newNode *Node
 			if path[i] {
@@ -646,27 +648,6 @@ func (mt *MerkleTree) recalculatePathUntilRoot(tx db.Tx, path []bool, node *Node
 	return nodeKey, err
 }
 
-// dbGet is a helper function to get the node of a key from the internal
-// storage.
-func (mt *MerkleTree) dbGet(k []byte) (NodeType, []byte, error) {
-	if bytes.Equal(k, HashZero[:]) {
-		return 0, nil, nil
-	}
-
-	value, err := mt.db.Get(k)
-	if err != nil {
-		return 0, nil, err
-	}
-
-	if len(value) < 2 {
-		return 0, nil, ErrInvalidDBValue
-	}
-	nodeType := value[0]
-	nodeBytes := value[1:]
-
-	return NodeType(nodeType), nodeBytes, nil
-}
-
 // dbInsert is a helper function to insert a node into a key in an open db
 // transaction.
 func (mt *MerkleTree) dbInsert(tx db.Tx, k []byte, t NodeType, data []byte) {
@@ -756,7 +737,7 @@ func NewProofFromBytes(bs []byte) (*Proof, error) {
 func (p *Proof) Bytes() []byte {
 	bsLen := proofFlagsLen + len(p.notempties) + ElemBytesLen*len(p.Siblings)
 	if p.NodeAux != nil {
-		bsLen += 2 * ElemBytesLen
+		bsLen += 2 * ElemBytesLen //nolint:gomnd
 	}
 	bs := make([]byte, bsLen)
 

merkletree_test.go

@@ -350,12 +350,12 @@ func TestGraphViz(t *testing.T) {
 	mt, err := NewMerkleTree(memory.NewMemoryStorage(), 10)
 	assert.Nil(t, err)
 
-	mt.Add(big.NewInt(1), big.NewInt(0))
-	mt.Add(big.NewInt(2), big.NewInt(0))
-	mt.Add(big.NewInt(3), big.NewInt(0))
-	mt.Add(big.NewInt(4), big.NewInt(0))
-	mt.Add(big.NewInt(5), big.NewInt(0))
-	mt.Add(big.NewInt(100), big.NewInt(0))
+	_ = mt.Add(big.NewInt(1), big.NewInt(0))
+	_ = mt.Add(big.NewInt(2), big.NewInt(0))
+	_ = mt.Add(big.NewInt(3), big.NewInt(0))
+	_ = mt.Add(big.NewInt(4), big.NewInt(0))
+	_ = mt.Add(big.NewInt(5), big.NewInt(0))
+	_ = mt.Add(big.NewInt(100), big.NewInt(0))
 
 	// mt.PrintGraphViz(nil)
 
@@ -381,7 +381,8 @@ node [fontname=Monospace,fontsize=10,shape=box]
 }
 `
 	w := bytes.NewBufferString("")
-	mt.GraphViz(w, nil)
+	err = mt.GraphViz(w, nil)
+	assert.Nil(t, err)
 	assert.Equal(t, []byte(expected), w.Bytes())
 }
 
@@ -415,7 +416,6 @@ func TestDelete(t *testing.T) {
 	err = mt.Delete(big.NewInt(1))
 	assert.Nil(t, err)
 	assert.Equal(t, "0", mt.Root().String())
-
 }
 
 func TestDelete2(t *testing.T) {