enable errorlint linter

.golangci.yml

@@ -1,5 +1,6 @@
 linters:
   enable:
+    - errorlint
     - misspell
     - revive
 

config/http_config.go

@@ -630,7 +630,7 @@ func (rt *authorizationCredentialsFileRoundTripper) RoundTrip(req *http.Request)
 	if len(req.Header.Get("Authorization")) == 0 {
 		b, err := os.ReadFile(rt.authCredentialsFile)
 		if err != nil {
-			return nil, fmt.Errorf("unable to read authorization credentials file %s: %s", rt.authCredentialsFile, err)
+			return nil, fmt.Errorf("unable to read authorization credentials file %s: %w", rt.authCredentialsFile, err)
 		}
 		authCredentials := strings.TrimSpace(string(b))
 
@@ -670,7 +670,7 @@ func (rt *basicAuthRoundTripper) RoundTrip(req *http.Request) (*http.Response, e
 	if rt.usernameFile != "" {
 		usernameBytes, err := os.ReadFile(rt.usernameFile)
 		if err != nil {
-			return nil, fmt.Errorf("unable to read basic auth username file %s: %s", rt.usernameFile, err)
+			return nil, fmt.Errorf("unable to read basic auth username file %s: %w", rt.usernameFile, err)
 		}
 		username = strings.TrimSpace(string(usernameBytes))
 	} else {
@@ -679,7 +679,7 @@ func (rt *basicAuthRoundTripper) RoundTrip(req *http.Request) (*http.Response, e
 	if rt.passwordFile != "" {
 		passwordBytes, err := os.ReadFile(rt.passwordFile)
 		if err != nil {
-			return nil, fmt.Errorf("unable to read basic auth password file %s: %s", rt.passwordFile, err)
+			return nil, fmt.Errorf("unable to read basic auth password file %s: %w", rt.passwordFile, err)
 		}
 		password = strings.TrimSpace(string(passwordBytes))
 	} else {
@@ -723,7 +723,7 @@ func (rt *oauth2RoundTripper) RoundTrip(req *http.Request) (*http.Response, erro
 	if rt.config.ClientSecretFile != "" {
 		data, err := os.ReadFile(rt.config.ClientSecretFile)
 		if err != nil {
-			return nil, fmt.Errorf("unable to read oauth2 client secret file %s: %s", rt.config.ClientSecretFile, err)
+			return nil, fmt.Errorf("unable to read oauth2 client secret file %s: %w", rt.config.ClientSecretFile, err)
 		}
 		secret = strings.TrimSpace(string(data))
 		rt.mtx.RLock()
@@ -977,7 +977,7 @@ func (c *TLSConfig) getClientCertificate(_ *tls.CertificateRequestInfo) (*tls.Ce
 	if c.CertFile != "" {
 		certData, err = os.ReadFile(c.CertFile)
 		if err != nil {
-			return nil, fmt.Errorf("unable to read specified client cert (%s): %s", c.CertFile, err)
+			return nil, fmt.Errorf("unable to read specified client cert (%s): %w", c.CertFile, err)
 		}
 	} else {
 		certData = []byte(c.Cert)
@@ -986,15 +986,15 @@ func (c *TLSConfig) getClientCertificate(_ *tls.CertificateRequestInfo) (*tls.Ce
 	if c.KeyFile != "" {
 		keyData, err = os.ReadFile(c.KeyFile)
 		if err != nil {
-			return nil, fmt.Errorf("unable to read specified client key (%s): %s", c.KeyFile, err)
+			return nil, fmt.Errorf("unable to read specified client key (%s): %w", c.KeyFile, err)
 		}
 	} else {
 		keyData = []byte(c.Key)
 	}
 
 	cert, err := tls.X509KeyPair(certData, keyData)
 	if err != nil {
-		return nil, fmt.Errorf("unable to use specified client cert (%s) & key (%s): %s", c.CertFile, c.KeyFile, err)
+		return nil, fmt.Errorf("unable to use specified client cert (%s) & key (%s): %w", c.CertFile, c.KeyFile, err)
 	}
 
 	return &cert, nil
@@ -1004,7 +1004,7 @@ func (c *TLSConfig) getClientCertificate(_ *tls.CertificateRequestInfo) (*tls.Ce
 func readCAFile(f string) ([]byte, error) {
 	data, err := os.ReadFile(f)
 	if err != nil {
-		return nil, fmt.Errorf("unable to load specified CA cert %s: %s", f, err)
+		return nil, fmt.Errorf("unable to load specified CA cert %s: %w", f, err)
 	}
 	return data, nil
 }

expfmt/bench_test.go

@@ -16,6 +16,7 @@ package expfmt
 import (
 	"bytes"
 	"compress/gzip"
+	"errors"
 	"io"
 	"os"
 	"testing"
@@ -101,7 +102,7 @@ func BenchmarkParseProto(b *testing.B) {
 		for {
 			family.Reset()
 			if _, err := pbutil.ReadDelimited(in, family); err != nil {
-				if err == io.EOF {
+				if errors.Is(err, io.EOF) {
 					break
 				}
 				b.Fatal(err)
@@ -129,7 +130,7 @@ func BenchmarkParseProtoGzip(b *testing.B) {
 		for {
 			family.Reset()
 			if _, err := pbutil.ReadDelimited(in, family); err != nil {
-				if err == io.EOF {
+				if errors.Is(err, io.EOF) {
 					break
 				}
 				b.Fatal(err)
@@ -156,7 +157,7 @@ func BenchmarkParseProtoMap(b *testing.B) {
 		for {
 			family := &dto.MetricFamily{}
 			if _, err := pbutil.ReadDelimited(in, family); err != nil {
-				if err == io.EOF {
+				if errors.Is(err, io.EOF) {
 					break
 				}
 				b.Fatal(err)

expfmt/decode_test.go

@@ -15,6 +15,7 @@ package expfmt
 
 import (
 	"bufio"
+	"errors"
 	"io"
 	"net/http"
 	"reflect"
@@ -84,7 +85,7 @@ mf2 4
 	for {
 		var smpls model.Vector
 		err := dec.Decode(&smpls)
-		if err == io.EOF {
+		if err != nil && errors.Is(err, io.EOF) {
 			break
 		}
 		if err != nil {
@@ -346,7 +347,7 @@ func TestProtoDecoder(t *testing.T) {
 		for {
 			var smpls model.Vector
 			err := dec.Decode(&smpls)
-			if err == io.EOF {
+			if err != nil && errors.Is(err, io.EOF) {
 				break
 			}
 			if scenario.fail {
@@ -505,7 +506,7 @@ func TestTextDecoderWithBufioReader(t *testing.T) {
 	for {
 		var mf dto.MetricFamily
 		if err := dec.Decode(&mf); err != nil {
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				break
 			}
 			t.Fatalf("Unexpected error: %v", err)

expfmt/text_parse.go

@@ -16,6 +16,7 @@ package expfmt
 import (
 	"bufio"
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"math"
@@ -112,7 +113,7 @@ func (p *TextParser) TextToMetricFamilies(in io.Reader) (map[string]*dto.MetricF
 	// stream. Turn this error into something nicer and more
 	// meaningful. (io.EOF is often used as a signal for the legitimate end
 	// of an input stream.)
-	if p.err == io.EOF {
+	if p.err != nil && errors.Is(p.err, io.EOF) {
 		p.parseError("unexpected end of input stream")
 	}
 	return p.metricFamiliesByName, p.err
@@ -146,7 +147,7 @@ func (p *TextParser) startOfLine() stateFn {
 		// which is not an error but the signal that we are done.
 		// Any other error that happens to align with the start of
 		// a line is still an error.
-		if p.err == io.EOF {
+		if errors.Is(p.err, io.EOF) {
 			p.err = nil
 		}
 		return nil

expfmt/text_parse_test.go

@@ -691,7 +691,7 @@ func TestTextParserStartOfLine(t *testing.T) {
 		if fn != nil {
 			t.Errorf("Unexpected non-nil function: %v", fn)
 		}
-		if p.err != in.err {
+		if p.err != nil && !errors.Is(p.err, in.err) {
 			t.Errorf("Unexpected error: %v, expected %v", p.err, in.err)
 		}
 	})

model/alert.go

@@ -90,13 +90,13 @@ func (a *Alert) Validate() error {
 		return fmt.Errorf("start time must be before end time")
 	}
 	if err := a.Labels.Validate(); err != nil {
-		return fmt.Errorf("invalid label set: %s", err)
+		return fmt.Errorf("invalid label set: %w", err)
 	}
 	if len(a.Labels) == 0 {
 		return fmt.Errorf("at least one label pair required")
 	}
 	if err := a.Annotations.Validate(); err != nil {
-		return fmt.Errorf("invalid annotations: %s", err)
+		return fmt.Errorf("invalid annotations: %w", err)
 	}
 	return nil
 }

model/silence.go

@@ -81,7 +81,7 @@ func (s *Silence) Validate() error {
 	}
 	for _, m := range s.Matchers {
 		if err := m.Validate(); err != nil {
-			return fmt.Errorf("invalid matcher: %s", err)
+			return fmt.Errorf("invalid matcher: %w", err)
 		}
 	}
 	if s.StartsAt.IsZero() {

model/value.go

@@ -274,7 +274,7 @@ func (s *Scalar) UnmarshalJSON(b []byte) error {
 
 	value, err := strconv.ParseFloat(f, 64)
 	if err != nil {
-		return fmt.Errorf("error parsing sample value: %s", err)
+		return fmt.Errorf("error parsing sample value: %w", err)
 	}
 	s.Value = SampleValue(value)
 	return nil