all: fix and suppress linter warnings

21 files changed, 61 insertions, 69 deletions

diff --git a/lib/email/dkim/dns.go b/lib/email/dkim/dns.go
index e19f2501..1aa86089 100644
--- a/lib/email/dkim/dns.go
+++ b/lib/email/dkim/dns.go
@@ -60,7 +60,7 @@ func lookupDNSTXT(dname string) (key *Key, err error) {
 		dns.QueryClassIN, []byte(dname))
 	if err != nil {
 		dnsClientPool.Put(dnsClient)
-		return nil, fmt.Errorf("dkim: LookupKey: " + err.Error())
+		return nil, fmt.Errorf("dkim: LookupKey: %w", err)
 	}
 	if dnsMsg.Header.RCode != dns.RCodeOK {
 		dnsClientPool.Put(dnsClient)
diff --git a/lib/email/dkim/key.go b/lib/email/dkim/key.go
index b7baae4a..2b1912ed 100644
--- a/lib/email/dkim/key.go
+++ b/lib/email/dkim/key.go
@@ -185,12 +185,12 @@ func (key *Key) set(t *tag) (err error) {
 	case tagDNSPublicKey:
 		pkey, err := base64.RawStdEncoding.DecodeString(string(t.value))
 		if err != nil {
-			err = fmt.Errorf("dkim: error decode public key: " + err.Error())
+			err = fmt.Errorf("dkim: error decode public key: %w", err)
 			return err
 		}
 		pk, err := x509.ParsePKIXPublicKey(pkey)
 		if err != nil {
-			err = fmt.Errorf("dkim: error parsing public key: " + err.Error())
+			err = fmt.Errorf("dkim: error parsing public key: %w", err)
 			return err
 		}
 
diff --git a/lib/email/dkim/signature.go b/lib/email/dkim/signature.go
index d3dce197..9378ac0d 100644
--- a/lib/email/dkim/signature.go
+++ b/lib/email/dkim/signature.go
@@ -294,7 +294,7 @@ func (sig *Signature) Sign(pk *rsa.PrivateKey, hashHeader []byte) (err error) {
 	rng := rand.Reader
 	b, err := rsa.SignPKCS1v15(rng, pk, cryptoHash, hashHeader)
 	if err != nil {
-		err = fmt.Errorf("email/dkim: failed to sign message: %s", err.Error())
+		err = fmt.Errorf("email/dkim: failed to sign message: %w", err)
 		return err
 	}
 
@@ -391,7 +391,7 @@ func (sig *Signature) Verify(key *Key, headerHash []byte) (err error) {
 	sigValue := make([]byte, base64.StdEncoding.DecodedLen(len(sig.Value)))
 	n, err := base64.StdEncoding.Decode(sigValue, sig.Value)
 	if err != nil {
-		return fmt.Errorf("email/dkim: failed to decode signature: %s", err.Error())
+		return fmt.Errorf("email/dkim: failed to decode signature: %w", err)
 	}
 	sigValue = sigValue[:n]
 
@@ -402,7 +402,7 @@ func (sig *Signature) Verify(key *Key, headerHash []byte) (err error) {
 
 	err = rsa.VerifyPKCS1v15(key.RSA, cryptoHash, headerHash, sigValue)
 	if err != nil {
-		err = fmt.Errorf("email/dkim: verification failed: %s", err.Error())
+		err = fmt.Errorf("email/dkim: verification failed: %w", err)
 	}
 
 	return err
diff --git a/lib/email/header.go b/lib/email/header.go
index 54e7ac36..236137e9 100644
--- a/lib/email/header.go
+++ b/lib/email/header.go
@@ -237,7 +237,7 @@ func (hdr *Header) SetMultipart() (err error) {
 		return fmt.Errorf("email.SetMultipart: %w", err)
 	}
 
-	hdr.Set(FieldTypeContentType, []byte(contentTypeMultipartAlternative))
+	err = hdr.Set(FieldTypeContentType, []byte(contentTypeMultipartAlternative))
 	if err != nil {
 		return fmt.Errorf("email.SetMultipart: %w", err)
 	}
diff --git a/lib/email/mime.go b/lib/email/mime.go
index 811a2e56..edc62202 100644
--- a/lib/email/mime.go
+++ b/lib/email/mime.go
@@ -49,7 +49,10 @@ func newMIME(contentType, content []byte) (mime *MIME, err error) {
 	var buf bytes.Buffer
 	content = append(content, []byte("\r\n")...)
 	w := quotedprintable.NewWriter(&buf)
-	w.Write(content)
+	_, err = w.Write(content)
+	if err != nil {
+		return nil, err
+	}
 	w.Close()
 
 	mime.Content = buf.Bytes()
diff --git a/lib/floats64/floats64.go b/lib/floats64/floats64.go
index 008e1338..1a75186d 100644
--- a/lib/floats64/floats64.go
+++ b/lib/floats64/floats64.go
@@ -330,7 +330,7 @@ func inplaceMerge(d []float64, idx []int, x, y, r int, asc bool) {
 	}
 }
 
-// (4.3.4) LET Y := the minimum value between x and r on `d`
+// (4.3.4) LET Y := the minimum value between x and r on `d`.
 func minY(d []float64, x, y *int, r int, asc bool) {
 	for *x < r {
 		if asc {
diff --git a/lib/http/client.go b/lib/http/client.go
index 67342fd9..661e57a8 100644
--- a/lib/http/client.go
+++ b/lib/http/client.go
@@ -75,7 +75,7 @@ func NewClient(serverURL string, headers http.Header, insecure bool) (client *Cl
 				MaxIdleConns:      100,
 				IdleConnTimeout:   90 * time.Second,
 				TLSClientConfig: &tls.Config{
-					InsecureSkipVerify: insecure,
+					InsecureSkipVerify: insecure, //nolint: gosec
 				},
 				TLSHandshakeTimeout:   10 * time.Second,
 				ExpectContinueTimeout: 1 * time.Second,
@@ -138,7 +138,7 @@ func (client *Client) PostForm(path string, params url.Values) (
 
 	httpReq, err := http.NewRequest(http.MethodPost, url, body)
 	if err != nil {
-		return nil, fmt.Errorf("Post: %w", err)
+		return nil, fmt.Errorf("client.PostForm: %w", err)
 	}
 
 	client.setHeaders(httpReq)
@@ -146,17 +146,17 @@ func (client *Client) PostForm(path string, params url.Values) (
 
 	httpRes, err := client.Client.Do(httpReq)
 	if err != nil {
-		return nil, fmt.Errorf("Post: %w", err)
+		return nil, fmt.Errorf("client.PostForm: %w", err)
 	}
 
 	resBody, err = ioutil.ReadAll(httpRes.Body)
 	if err != nil {
-		return nil, fmt.Errorf("Post: %w", err)
+		return nil, fmt.Errorf("client.PostForm: %w", err)
 	}
 
 	err = httpRes.Body.Close()
 	if err != nil {
-		return nil, fmt.Errorf("Post: %w", err)
+		return nil, fmt.Errorf("client.PostForm: %w", err)
 	}
 
 	return client.uncompress(httpRes, resBody)
@@ -180,7 +180,7 @@ func (client *Client) PostFormData(path string, params map[string][]byte) (
 
 	httpReq, err := http.NewRequest(http.MethodPost, url, body)
 	if err != nil {
-		return nil, fmt.Errorf("Post: %w", err)
+		return nil, fmt.Errorf("http: PostFormData: %w", err)
 	}
 
 	client.setHeaders(httpReq)
diff --git a/lib/http/responsetype.go b/lib/http/responsetype.go
index 3cb4254d..ecd11d6f 100644
--- a/lib/http/responsetype.go
+++ b/lib/http/responsetype.go
@@ -4,7 +4,7 @@
 
 package http
 
-// ResponseType define type for HTTP response
+// ResponseType define type for HTTP response.
 type ResponseType int
 
 // List of valid response type.
diff --git a/lib/http/serveroptions.go b/lib/http/serveroptions.go
index 71278857..13cd6ac5 100644
--- a/lib/http/serveroptions.go
+++ b/lib/http/serveroptions.go
@@ -37,28 +37,23 @@ type ServerOptions struct {
 	// This field is optional.
 	Excludes []string
 
-	// CORSAllowCredentials indicates whether or not the actual request
-	// can be made using credentials.
-	CORSAllowCredentials bool
-
 	// CORSAllowOrigins contains global list of cross-site Origin that are
 	// allowed during preflight requests by the OPTIONS method.
 	// The list is case-sensitive.
 	// To allow all Origin, one must add "*" string to the list.
-	CORSAllowOrigins    []string
-	corsAllowOriginsAll bool // flag to indicate wildcards on list.
+	CORSAllowOrigins []string
 
 	// CORSAllowHeaders contains global list of allowed headers during
 	// preflight requests by the OPTIONS method.
 	// The list is case-insensitive.
 	// To allow all headers, one must add "*" string to the list.
-	CORSAllowHeaders    []string
-	corsAllowHeadersAll bool // flag to indicate wildcards on list.
+	CORSAllowHeaders []string
 
 	// CORSExposeHeaders contains list of allowed headers.
 	// This list will be send when browser request OPTIONS without
 	// request-method.
 	CORSExposeHeaders []string
+	exposeHeaders     string
 
 	// CORSMaxAge gives the value in seconds for how long the response to
 	// the preflight request can be cached for without sending another
@@ -66,11 +61,16 @@ type ServerOptions struct {
 	CORSMaxAge int
 	corsMaxAge string
 
+	// CORSAllowCredentials indicates whether or not the actual request
+	// can be made using credentials.
+	CORSAllowCredentials bool
+
 	// Development if its true, the Root file system is served by reading
 	// the content directly instead of using memory file system.
 	Development bool
 
-	exposeHeaders string
+	corsAllowHeadersAll bool // flag to indicate wildcards on list.
+	corsAllowOriginsAll bool // flag to indicate wildcards on list.
 }
 
 func (opts *ServerOptions) init() {
diff --git a/lib/hunspell/hunspell.go b/lib/hunspell/hunspell.go
index ba87b543..b961b574 100644
--- a/lib/hunspell/hunspell.go
+++ b/lib/hunspell/hunspell.go
@@ -81,7 +81,7 @@ const (
 	optSFX = "SFX"
 )
 
-// List of affix file other options/
+// List of affix file other options.
 const (
 	optCircumfix     = "CIRCUMFIX"
 	optForbiddenWord = "FORBIDDENWORD"
diff --git a/lib/ini/ini.go b/lib/ini/ini.go
index ea0bc637..38138272 100644
--- a/lib/ini/ini.go
+++ b/lib/ini/ini.go
@@ -91,12 +91,12 @@ func Marshal(v interface{}) (b []byte, err error) {
 		return nil, fmt.Errorf("marshal: expecting struct, got %v", kind)
 	}
 
-	ini := &Ini{}
+	in := &Ini{}
 
-	marshalStruct(ini, rtipe, rvalue)
+	marshalStruct(in, rtipe, rvalue)
 
 	buf := bytes.NewBuffer(nil)
-	err = ini.Write(buf)
+	err = in.Write(buf)
 	if err != nil {
 		return nil, err
 	}
@@ -239,7 +239,7 @@ func (in *Ini) Unmarshal(v interface{}) (err error) {
 }
 
 //nolint: gocyclo
-func (ini *Ini) unmarshalToStruct(rtipe reflect.Type, rvalue reflect.Value) {
+func (in *Ini) unmarshalToStruct(rtipe reflect.Type, rvalue reflect.Value) {
 	numField := rtipe.NumField()
 	if numField == 0 {
 		return
@@ -255,7 +255,7 @@ func (ini *Ini) unmarshalToStruct(rtipe reflect.Type, rvalue reflect.Value) {
 			continue
 		}
 
-		tag := field.Tag.Get("ini")
+		tag := field.Tag.Get(fieldTagName)
 		if len(tag) == 0 && kind != reflect.Struct {
 			continue
 		}
@@ -290,18 +290,18 @@ func (ini *Ini) unmarshalToStruct(rtipe reflect.Type, rvalue reflect.Value) {
 
 		switch kind {
 		case reflect.Bool:
-			valString, _ := ini.Get(sec, sub, key, "")
+			valString, _ := in.Get(sec, sub, key, "")
 			if IsValueBoolTrue(valString) {
 				fvalue.SetBool(true)
 			}
 
 		case reflect.String:
-			valString, _ := ini.Get(sec, sub, key, "")
+			valString, _ := in.Get(sec, sub, key, "")
 			fvalue.SetString(valString)
 
 		case reflect.Int, reflect.Int8, reflect.Int16,
 			reflect.Int32, reflect.Int64:
-			valString, _ := ini.Get(sec, sub, key, "")
+			valString, _ := in.Get(sec, sub, key, "")
 
 			_, ok := fvalue.Interface().(time.Duration)
 			if ok {
@@ -321,7 +321,7 @@ func (ini *Ini) unmarshalToStruct(rtipe reflect.Type, rvalue reflect.Value) {
 
 		case reflect.Uint, reflect.Uint8, reflect.Uint16,
 			reflect.Uint32, reflect.Uint64:
-			valString, _ := ini.Get(sec, sub, key, "")
+			valString, _ := in.Get(sec, sub, key, "")
 
 			u64, err := strconv.ParseUint(valString, 10, 64)
 			if err != nil {
@@ -330,7 +330,7 @@ func (ini *Ini) unmarshalToStruct(rtipe reflect.Type, rvalue reflect.Value) {
 			fvalue.SetUint(u64)
 
 		case reflect.Float32, reflect.Float64:
-			valString, _ := ini.Get(sec, sub, key, "")
+			valString, _ := in.Get(sec, sub, key, "")
 
 			f64, err := strconv.ParseFloat(valString, 64)
 			if err != nil {
@@ -339,11 +339,11 @@ func (ini *Ini) unmarshalToStruct(rtipe reflect.Type, rvalue reflect.Value) {
 			fvalue.SetFloat(f64)
 
 		case reflect.Array:
-			vals := ini.Gets(sec, sub, key)
+			vals := in.Gets(sec, sub, key)
 			fvalue.Set(unmarshalSlice(ftype.Elem(), fvalue, vals))
 
 		case reflect.Slice:
-			vals := ini.Gets(sec, sub, key)
+			vals := in.Gets(sec, sub, key)
 			fvalue.Set(unmarshalSlice(ftype.Elem(), fvalue, vals))
 
 		case reflect.Map:
@@ -351,7 +351,7 @@ func (ini *Ini) unmarshalToStruct(rtipe reflect.Type, rvalue reflect.Value) {
 				continue
 			}
 
-			vals := ini.AsMap(sec, sub)
+			vals := in.AsMap(sec, sub)
 			amap := reflect.MakeMap(ftype)
 			fvalue.Set(unmarshalMap(ftype.Elem(), amap, vals))
 
@@ -361,7 +361,7 @@ func (ini *Ini) unmarshalToStruct(rtipe reflect.Type, rvalue reflect.Value) {
 				kind = ftype.Kind()
 			}
 
-			valString, _ := ini.Get(sec, sub, key, "")
+			valString, _ := in.Get(sec, sub, key, "")
 
 			ptrval := reflect.New(ftype)
 			unmarshalPtr(ftype, ptrval.Elem(), valString)
@@ -372,7 +372,7 @@ func (ini *Ini) unmarshalToStruct(rtipe reflect.Type, rvalue reflect.Value) {
 
 			_, ok := vi.(time.Time)
 			if ok {
-				valString, _ := ini.Get(sec, sub, key, "")
+				valString, _ := in.Get(sec, sub, key, "")
 
 				t, err := time.Parse(layout, valString)
 				if err != nil {
@@ -383,7 +383,7 @@ func (ini *Ini) unmarshalToStruct(rtipe reflect.Type, rvalue reflect.Value) {
 				continue
 			}
 
-			ini.unmarshalToStruct(reflect.TypeOf(vi), fvalue.Addr().Elem())
+			in.unmarshalToStruct(reflect.TypeOf(vi), fvalue.Addr().Elem())
 
 		case reflect.Invalid, reflect.Chan, reflect.Func,
 			reflect.UnsafePointer, reflect.Interface:
diff --git a/lib/ints/ints.go b/lib/ints/ints.go
index 188342d7..aea2414a 100644
--- a/lib/ints/ints.go
+++ b/lib/ints/ints.go
@@ -393,7 +393,7 @@ func inplaceMultiswap(d []int, idx []int, x, y, ylast int) int {
 	return y
 }
 
-// (4.3.4) LET Y := the minimum value between x and r on `d`
+// (4.3.4) LET Y := the minimum value between x and r on `d`.
 func minY(d []int, x, y *int, r int, asc bool) {
 	for *x < r {
 		if asc {
diff --git a/lib/ints64/ints64.go b/lib/ints64/ints64.go
index 1ae8c484..9d05a30a 100644
--- a/lib/ints64/ints64.go
+++ b/lib/ints64/ints64.go
@@ -326,7 +326,7 @@ func inplaceMerge(d []int64, idx []int, x, y, r int, asc bool) {
 	}
 }
 
-// (4.3.4) LET Y := the minimum value between x and r on `d`
+// (4.3.4) LET Y := the minimum value between x and r on `d`.
 func minY(d []int64, x, y *int, r int, asc bool) {
 	for *x < r {
 		if asc {
diff --git a/lib/json/json_test.go b/lib/json/json_test.go
index 1efa9708..d1779f22 100644
--- a/lib/json/json_test.go
+++ b/lib/json/json_test.go
@@ -89,7 +89,7 @@ func TestUnescapeString(t *testing.T) {
 		exp: `	this\ is
 		//\"☺"`,
 	}, {
-		in: `\u0002\b\f\u000E\u000F\u0010\u0014\u001E\u001F\u263A `, //nolint: stylecheck
+		in: `\u0002\b\f\u000E\u000F\u0010\u0014\u001E\u001F\u263A `,
 		exp: `☺ `}, { //nolint: stylecheck
 		in:     `\uerror`,
 		expErr: `strconv.ParseUint: parsing "erro": invalid syntax`,
diff --git a/lib/memfs/generate.go b/lib/memfs/generate.go
index 3a9455ac..72bacba7 100644
--- a/lib/memfs/generate.go
+++ b/lib/memfs/generate.go
@@ -37,13 +37,13 @@ func (mfs *MemFS) GoGenerate(pkgName, out, contentEncoding string) (err error) {
 
 	f, err := os.Create(out)
 	if err != nil {
-		return fmt.Errorf("memfs: GoGenerate: " + err.Error())
+		return fmt.Errorf("memfs: GoGenerate: %w", err)
 	}
 
 	if len(contentEncoding) > 0 {
 		err = mfs.ContentEncode(contentEncoding)
 		if err != nil {
-			return fmt.Errorf("GoGenerate: " + err.Error())
+			return fmt.Errorf("GoGenerate: %w", err)
 		}
 	}
 
@@ -81,11 +81,11 @@ func (mfs *MemFS) GoGenerate(pkgName, out, contentEncoding string) (err error) {
 
 	err = f.Close()
 	if err != nil {
-		return fmt.Errorf("memfs: GoGenerate: " + err.Error())
+		return fmt.Errorf("memfs: GoGenerate: %w", err)
 	}
 
 	return nil
 fail:
 	_ = f.Close()
-	return fmt.Errorf("memfs: GoGenerate: " + err.Error())
+	return fmt.Errorf("memfs: GoGenerate: %w", err)
 }
diff --git a/lib/memfs/generate_test/memfs_generate_test.go b/lib/memfs/generate_test/memfs_generate_test.go
index e27ce17c..3d1b886a 100644
--- a/lib/memfs/generate_test/memfs_generate_test.go
+++ b/lib/memfs/generate_test/memfs_generate_test.go
@@ -5,10 +5,8 @@
 package test
 
 import (
-	"os"
 	"path/filepath"
 	"sort"
-	"strings"
 	"testing"
 
 	"github.com/shuLhan/share/lib/memfs"
@@ -16,13 +14,6 @@ import (
 )
 
 func TestGeneratePathNode(t *testing.T) {
-	wd, err := os.Getwd()
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	wd = strings.TrimSuffix(wd, "generate_test")
-
 	expRoot := &memfs.Node{
 		SysPath: "testdata",
 		Path:    "/",
diff --git a/lib/memfs/memfs.go b/lib/memfs/memfs.go
index 0ea7caa4..ebfb72d0 100644
--- a/lib/memfs/memfs.go
+++ b/lib/memfs/memfs.go
@@ -143,12 +143,12 @@ func (mfs *MemFS) AddFile(path string) (*Node, error) {
 
 		fi, err := os.Stat(path)
 		if err != nil {
-			return nil, fmt.Errorf("memfs.AddFile: " + err.Error())
+			return nil, fmt.Errorf("memfs.AddFile: %w", err)
 		}
 
 		node, err = NewNode(parent, fi, mfs.withContent)
 		if err != nil {
-			return nil, fmt.Errorf("memfs.AddFile: " + err.Error())
+			return nil, fmt.Errorf("memfs.AddFile: %w", err)
 		}
 
 		if parent == nil {
@@ -196,12 +196,12 @@ func (mfs *MemFS) ContentEncode(encoding string) (err error) {
 
 		_, err = encoder.Write(node.V)
 		if err != nil {
-			return fmt.Errorf("memfs.ContentEncode: " + err.Error())
+			return fmt.Errorf("memfs.ContentEncode: %w", err)
 		}
 
 		err = encoder.Close()
 		if err != nil {
-			return fmt.Errorf("memfs.ContentEncode: " + err.Error())
+			return fmt.Errorf("memfs.ContentEncode: %w", err)
 		}
 
 		node.V = make([]byte, buf.Len())
diff --git a/lib/memfs/node.go b/lib/memfs/node.go
index 51e83525..8bbf0fe7 100644
--- a/lib/memfs/node.go
+++ b/lib/memfs/node.go
@@ -360,8 +360,8 @@ func (leaf *Node) update(newInfo os.FileInfo, withContent bool) (err error) {
 	if newInfo == nil {
 		newInfo, err = os.Stat(leaf.SysPath)
 		if err != nil {
-			return fmt.Errorf("lib/memfs: Node.update %q: %s",
-				leaf.Path, err.Error())
+			return fmt.Errorf("lib/memfs: Node.update %q: %w",
+				leaf.Path, err)
 		}
 	}
 
diff --git a/lib/mining/classifier/cart/cart.go b/lib/mining/classifier/cart/cart.go
index 1745bb8f..5cf20c8d 100644
--- a/lib/mining/classifier/cart/cart.go
+++ b/lib/mining/classifier/cart/cart.go
@@ -257,7 +257,7 @@ func (runtime *Runtime) splitTreeByGain(claset tabula.ClasetInterface) (
 }
 
 // SelectRandomFeature if NRandomFeature is greater than zero, select and
-// compute gain in n random features instead of in all features
+// compute gain in n random features instead of in all features.
 func (runtime *Runtime) SelectRandomFeature(claset tabula.ClasetInterface) {
 	if runtime.NRandomFeature <= 0 {
 		// all features selected
diff --git a/lib/net/html/example_node_iterator_test.go b/lib/net/html/example_node_iterator_test.go
index b5e82db4..6fa3838f 100644
--- a/lib/net/html/example_node_iterator_test.go
+++ b/lib/net/html/example_node_iterator_test.go
@@ -52,7 +52,7 @@ func ExampleParse() {
 	//html
 }
 
-func ExampleNodeIterator_Set() {
+func ExampleNodeIterator_SetNext() {
 	rawHTML := `
 <ul>
 	<li>
diff --git a/lib/sql/client.go b/lib/sql/client.go
index 82bb8c20..81f85961 100644
--- a/lib/sql/client.go
+++ b/lib/sql/client.go
@@ -19,9 +19,7 @@ import (
 )
 
 const (
-	sqlExtension  = ".sql"
-	sqlComment    = "--"
-	sqlTerminator = ';'
+	sqlExtension = ".sql"
 )
 
 //