Use errors.New instead of fmt.Errorf w/o args (#3004)

internal/codegenerator/parse_req_test.go

@@ -2,7 +2,7 @@ package codegenerator_test
 
 import (
 	"bytes"
-	"fmt"
+	"errors"
 	"io"
 	"strings"
 	"testing"
@@ -66,5 +66,5 @@ type invalidReader struct {
 }
 
 func (*invalidReader) Read(p []byte) (int, error) {
-	return 0, fmt.Errorf("invalid reader")
+	return 0, errors.New("invalid reader")
 }

internal/descriptor/services.go

@@ -1,6 +1,7 @@
 package descriptor
 
 import (
+	"errors"
 	"fmt"
 	"strings"
 
@@ -132,7 +133,7 @@ func (r *Registry) newMethod(svc *Service, md *descriptorpb.MethodDescriptorProt
 		tmpl := parsed.Compile()
 
 		if md.GetClientStreaming() && len(tmpl.Fields) > 0 {
-			return nil, fmt.Errorf("cannot use path parameter in client streaming")
+			return nil, errors.New("cannot use path parameter in client streaming")
 		}
 
 		b := &Binding{
@@ -259,13 +260,13 @@ func (r *Registry) newParam(meth *Method, path string) (Parameter, error) {
 }
 
 func (r *Registry) newBody(meth *Method, path string) (*Body, error) {
-	msg := meth.RequestType
 	switch path {
 	case "":
 		return nil, nil
 	case "*":
 		return &Body{FieldPath: nil}, nil
 	}
+	msg := meth.RequestType
 	fields, err := r.resolveFieldPath(msg, path, false)
 	if err != nil {
 		return nil, err

internal/httprule/parse.go

@@ -1,6 +1,7 @@
 package httprule
 
 import (
+	"errors"
 	"fmt"
 	"strings"
 )
@@ -164,7 +165,7 @@ func (p *parser) segment() (segment, error) {
 
 	v, err := p.variable()
 	if err != nil {
-		return nil, fmt.Errorf("segment neither wildcards, literal or variable: %v", err)
+		return nil, fmt.Errorf("segment neither wildcards, literal or variable: %w", err)
 	}
 	return v, err
 }
@@ -213,7 +214,7 @@ func (p *parser) fieldPath() (string, error) {
 	}
 	components := []string{c}
 	for {
-		if _, err = p.accept("."); err != nil {
+		if _, err := p.accept("."); err != nil {
 			return strings.Join(components, "."), nil
 		}
 		c, err := p.accept(typeIdent)
@@ -237,10 +238,8 @@ const (
 	typeEOF     = termType("$")
 )
 
-const (
-	// eof is the terminal symbol which always appears at the end of token sequence.
-	eof = "\u0000"
-)
+// eof is the terminal symbol which always appears at the end of token sequence.
+const eof = "\u0000"
 
 // accept tries to accept a token in "p".
 // This function consumes a token and returns it if it matches to the specified "term".
@@ -334,7 +333,7 @@ func expectPChars(t string) error {
 // expectIdent determines if "ident" is a valid identifier in .proto schema ([[:alpha:]_][[:alphanum:]_]*).
 func expectIdent(ident string) error {
 	if ident == "" {
-		return fmt.Errorf("empty identifier")
+		return errors.New("empty identifier")
 	}
 	for pos, r := range ident {
 		switch {

protoc-gen-grpc-gateway/internal/gengateway/generator.go

@@ -13,9 +13,7 @@ import (
 	"google.golang.org/protobuf/types/pluginpb"
 )
 
-var (
-	errNoTargetService = errors.New("no target service defined in the file")
-)
+var errNoTargetService = errors.New("no target service defined in the file")
 
 type generator struct {
 	reg                *descriptor.Registry
@@ -76,7 +74,7 @@ func (g *generator) Generate(targets []*descriptor.File) ([]*descriptor.Response
 		glog.V(1).Infof("Processing %s", file.GetName())
 
 		code, err := g.generate(file)
-		if err == errNoTargetService {
+		if errors.Is(err, errNoTargetService) {
 			glog.V(1).Infof("%s: %v", file.GetName(), err)
 			continue
 		}

protoc-gen-openapiv2/internal/genopenapi/template.go

@@ -1076,7 +1076,7 @@ func renderServices(services []*descriptor.Service, paths openapiPathsObject, re
 					case descriptorpb.FieldDescriptorProto_TYPE_GROUP, descriptorpb.FieldDescriptorProto_TYPE_MESSAGE:
 						if descriptor.IsWellKnownType(parameter.Target.GetTypeName()) {
 							if parameter.IsRepeated() {
-								return fmt.Errorf("only primitive and enum types are allowed in repeated path parameters")
+								return errors.New("only primitive and enum types are allowed in repeated path parameters")
 							}
 							schema := schemaOfField(parameter.Target, reg, customRefs)
 							paramType = schema.Type
@@ -2113,7 +2113,7 @@ func updateOpenAPIDataFromComments(reg *descriptor.Registry, swaggerObject inter
 			}
 			if len(description) > 0 {
 				if !descriptionValue.CanSet() {
-					return fmt.Errorf("encountered object type with a summary, but no description")
+					return errors.New("encountered object type with a summary, but no description")
 				}
 				// overrides the schema value only if it's empty
 				// keep the comment precedence when updating the package definition

runtime/errors_test.go

@@ -2,7 +2,7 @@ package runtime_test
 
 import (
 	"context"
-	"fmt"
+	"errors"
 	"net/http"
 	"net/http/httptest"
 	"strconv"
@@ -32,7 +32,7 @@ func TestDefaultHTTPError(t *testing.T) {
 		details     string
 	}{
 		{
-			err:         fmt.Errorf("example error"),
+			err:         errors.New("example error"),
 			status:      http.StatusInternalServerError,
 			marshaler:   &runtime.JSONPb{},
 			contentType: "application/json",
@@ -54,7 +54,7 @@ func TestDefaultHTTPError(t *testing.T) {
 			details:     "type.googleapis.com/google.rpc.PreconditionFailure",
 		},
 		{
-			err:         fmt.Errorf("example error"),
+			err:         errors.New("example error"),
 			status:      http.StatusInternalServerError,
 			marshaler:   &CustomMarshaler{&runtime.JSONPb{}},
 			contentType: "Custom-Content-Type",

runtime/fieldmask_test.go

@@ -2,7 +2,7 @@ package runtime
 
 import (
 	"bytes"
-	"fmt"
+	"errors"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -260,7 +260,7 @@ func TestFieldMaskErrors(t *testing.T) {
 		{
 			name:        "object under scalar",
 			input:       `{"uuid": {"a": "x"}}`,
-			expectedErr: fmt.Errorf("JSON structure did not match request type"),
+			expectedErr: errors.New("JSON structure did not match request type"),
 		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {