Fix staticcheck ST1005 errors in generated Go client (#13633)

* Fix staticcheck ST1005 errors in go client

* Samples updated

* sample test fix for openapiv3 petstore go client

modules/openapi-generator/src/main/resources/go/client.mustache

@@ -127,7 +127,7 @@ func typeCheckParameter(obj interface{}, expected string, name string) error {
 
 	// Check the type is as expected.
 	if reflect.TypeOf(obj).String() != expected {
-		return fmt.Errorf("Expected %s to be of type %s but received %s.", name, expected, reflect.TypeOf(obj).String())
+		return fmt.Errorf("expected %s to be of type %s but received %s", name, expected, reflect.TypeOf(obj).String())
 	}
 	return nil
 }
@@ -514,7 +514,7 @@ func setBody(body interface{}, contentType string) (bodyBuf *bytes.Buffer, err e
 	}
 
 	if bodyBuf.Len() == 0 {
-		err = fmt.Errorf("Invalid body type %s\n", contentType)
+		err = fmt.Errorf("invalid body type %s\n", contentType)
 		return nil, err
 	}
 	return bodyBuf, nil

modules/openapi-generator/src/main/resources/go/configuration.mustache

@@ -207,7 +207,7 @@ func (c *Configuration) AddDefaultHeader(key string, value string) {
 // URL formats template on a index using given variables
 func (sc ServerConfigurations) URL(index int, variables map[string]string) (string, error) {
 	if index < 0 || len(sc) <= index {
-		return "", fmt.Errorf("Index %v out of range %v", index, len(sc)-1)
+		return "", fmt.Errorf("index %v out of range %v", index, len(sc)-1)
 	}
 	server := sc[index]
 	url := server.URL
@@ -222,7 +222,7 @@ func (sc ServerConfigurations) URL(index int, variables map[string]string) (stri
 				}
 			}
 			if !found {
-				return "", fmt.Errorf("The variable %s in the server URL has invalid value %v. Must be %v", name, value, variable.EnumValues)
+				return "", fmt.Errorf("the variable %s in the server URL has invalid value %v. Must be %v", name, value, variable.EnumValues)
 			}
 			url = strings.Replace(url, "{"+name+"}", value, -1)
 		} else {

modules/openapi-generator/src/main/resources/go/model_anyof.mustache

@@ -22,7 +22,7 @@ func (dst *{{classname}}) UnmarshalJSON(data []byte) error {
 	var jsonDict map[string]interface{}
 	err = json.Unmarshal(data, &jsonDict)
 	if err != nil {
-		return fmt.Errorf("Failed to unmarshal JSON into map for the discriminator lookup.")
+		return fmt.Errorf("failed to unmarshal JSON into map for the discriminator lookup")
 	}
 
 	{{/-first}}
@@ -59,7 +59,7 @@ func (dst *{{classname}}) UnmarshalJSON(data []byte) error {
 	}
 
 	{{/anyOf}}
-	return fmt.Errorf("Data failed to match schemas in anyOf({{classname}})")
+	return fmt.Errorf("data failed to match schemas in anyOf({{classname}})")
 }
 
 // Marshal data from the first non-nil pointers in the struct to JSON

modules/openapi-generator/src/main/resources/go/model_oneof.mustache

@@ -33,7 +33,7 @@ func (dst *{{classname}}) UnmarshalJSON(data []byte) error {
 	var jsonDict map[string]interface{}
 	err = newStrictDecoder(data).Decode(&jsonDict)
 	if err != nil {
-		return fmt.Errorf("Failed to unmarshal JSON into map for the discriminator lookup.")
+		return fmt.Errorf("failed to unmarshal JSON into map for the discriminator lookup")
 	}
 
 	{{/-first}}
@@ -45,7 +45,7 @@ func (dst *{{classname}}) UnmarshalJSON(data []byte) error {
 			return nil // data stored in dst.{{{modelName}}}, return on the first match
 		} else {
 			dst.{{{modelName}}} = nil
-			return fmt.Errorf("Failed to unmarshal {{classname}} as {{{modelName}}}: %s", err.Error())
+			return fmt.Errorf("failed to unmarshal {{classname}} as {{{modelName}}}: %s", err.Error())
 		}
 	}
 
@@ -75,11 +75,11 @@ func (dst *{{classname}}) UnmarshalJSON(data []byte) error {
                 dst.{{#lambda.type-to-name}}{{{.}}}{{/lambda.type-to-name}} = nil
                 {{/oneOf}}
 
-                return fmt.Errorf("Data matches more than one schema in oneOf({{classname}})")
+                return fmt.Errorf("data matches more than one schema in oneOf({{classname}})")
         } else if match == 1 {
                 return nil // exactly one match
         } else { // no match
-                return fmt.Errorf("Data failed to match schemas in oneOf({{classname}})")
+                return fmt.Errorf("data failed to match schemas in oneOf({{classname}})")
         }
 	{{/discriminator}}
 	{{/useOneOfDiscriminatorLookup}}
@@ -106,11 +106,11 @@ func (dst *{{classname}}) UnmarshalJSON(data []byte) error {
 		dst.{{#lambda.type-to-name}}{{{.}}}{{/lambda.type-to-name}} = nil
 		{{/oneOf}}
 
-		return fmt.Errorf("Data matches more than one schema in oneOf({{classname}})")
+		return fmt.Errorf("data matches more than one schema in oneOf({{classname}})")
 	} else if match == 1 {
 		return nil // exactly one match
 	} else { // no match
-		return fmt.Errorf("Data failed to match schemas in oneOf({{classname}})")
+		return fmt.Errorf("data failed to match schemas in oneOf({{classname}})")
 	}
 	{{/useOneOfDiscriminatorLookup}}
 }

modules/openapi-generator/src/main/resources/go/signing.mustache

@@ -126,26 +126,26 @@ func (h *HttpSignatureAuth) SetPrivateKey(privateKey string) error {
 // are invalid.
 func (h *HttpSignatureAuth) ContextWithValue(ctx context.Context) (context.Context, error) {
 	if h.KeyId == "" {
-		return nil, fmt.Errorf("Key ID must be specified")
+		return nil, fmt.Errorf("key ID must be specified")
 	}
 	if h.PrivateKeyPath == "" && h.privateKey == nil {
-		return nil, fmt.Errorf("Private key path must be specified")
+		return nil, fmt.Errorf("private key path must be specified")
 	}
 	if _, ok := supportedSigningSchemes[h.SigningScheme]; !ok {
-		return nil, fmt.Errorf("Invalid signing scheme: '%v'", h.SigningScheme)
+		return nil, fmt.Errorf("invalid signing scheme: '%v'", h.SigningScheme)
 	}
 	m := make(map[string]bool)
 	for _, h := range h.SignedHeaders {
 		if strings.EqualFold(h, HttpHeaderAuthorization) {
-			return nil, fmt.Errorf("Signed headers cannot include the 'Authorization' header")
+			return nil, fmt.Errorf("signed headers cannot include the 'Authorization' header")
 		}
 		m[h] = true
 	}
 	if len(m) != len(h.SignedHeaders) {
-		return nil, fmt.Errorf("List of signed headers cannot have duplicate names")
+		return nil, fmt.Errorf("list of signed headers cannot have duplicate names")
 	}
 	if h.SignatureMaxValidity < 0 {
-		return nil, fmt.Errorf("Signature max validity must be a positive value")
+		return nil, fmt.Errorf("signature max validity must be a positive value")
 	}
 	if err := h.loadPrivateKey(); err != nil {
 		return nil, err
@@ -168,7 +168,7 @@ func (h *HttpSignatureAuth) GetPublicKey() (crypto.PublicKey, error) {
 	default:
 		// Do not change '%T' to anything else such as '%v'!
 		// The value of the private key must not be returned.
-		return nil, fmt.Errorf("Unsupported key: %T", h.privateKey)
+		return nil, fmt.Errorf("unsupported key: %T", h.privateKey)
 	}
 }
 
@@ -181,7 +181,7 @@ func (h *HttpSignatureAuth) loadPrivateKey() (err error) {
 	var file *os.File
 	file, err = os.Open(h.PrivateKeyPath)
 	if err != nil {
-		return fmt.Errorf("Cannot load private key '%s'. Error: %v", h.PrivateKeyPath, err)
+		return fmt.Errorf("cannot load private key '%s'. Error: %v", h.PrivateKeyPath, err)
 	}
 	defer func() {
 		err = file.Close()
@@ -199,7 +199,7 @@ func (h *HttpSignatureAuth) parsePrivateKey(priv []byte) error {
 	pemBlock, _ := pem.Decode(priv)
 	if pemBlock == nil {
 		// No PEM data has been found.
-		return fmt.Errorf("File '%s' does not contain PEM data", h.PrivateKeyPath)
+		return fmt.Errorf("file '%s' does not contain PEM data", h.PrivateKeyPath)
 	}
 	var privKey []byte
 	var err error
@@ -225,7 +225,7 @@ func (h *HttpSignatureAuth) parsePrivateKey(priv []byte) error {
 			return err
 		}
 	default:
-		return fmt.Errorf("Key '%s' is not supported", pemBlock.Type)
+		return fmt.Errorf("key '%s' is not supported", pemBlock.Type)
 	}
 	return nil
 }
@@ -248,7 +248,7 @@ func SignRequest(
 	auth HttpSignatureAuth) error {
 
 	if auth.privateKey == nil {
-		return fmt.Errorf("Private key is not set")
+		return fmt.Errorf("private key is not set")
 	}
 	now := time.Now()
 	date := now.UTC().Format(http.TimeFormat)
@@ -262,7 +262,7 @@ func SignRequest(
 	var expiresUnix float64
 
 	if auth.SignatureMaxValidity < 0 {
-		return fmt.Errorf("Signature validity must be a positive value")
+		return fmt.Errorf("signature validity must be a positive value")
 	}
 	if auth.SignatureMaxValidity > 0 {
 		e := now.Add(auth.SignatureMaxValidity)
@@ -278,10 +278,10 @@ func SignRequest(
 		h = crypto.SHA256
 		prefix = "SHA-256="
 	default:
-		return fmt.Errorf("Unsupported signature scheme: %v", auth.SigningScheme)
+		return fmt.Errorf("unsupported signature scheme: %v", auth.SigningScheme)
 	}
 	if !h.Available() {
-		return fmt.Errorf("Hash '%v' is not available", h)
+		return fmt.Errorf("hash '%v' is not available", h)
 	}
 
 	// Build the "(request-target)" signature header.
@@ -308,7 +308,7 @@ func SignRequest(
 		m[h] = true
 	}
 	if len(m) != len(signedHeaders) {
-		return fmt.Errorf("List of signed headers must not have any duplicates")
+		return fmt.Errorf("list of signed headers must not have any duplicates")
 	}
 	hasCreatedParameter := false
 	hasExpiresParameter := false
@@ -317,7 +317,7 @@ func SignRequest(
 		var value string
 		switch header {
 		case strings.ToLower(HttpHeaderAuthorization):
-			return fmt.Errorf("Cannot include the 'Authorization' header as a signed header.")
+			return fmt.Errorf("cannot include the 'Authorization' header as a signed header")
 		case HttpSignatureParameterRequestTarget:
 			value = requestTarget
 		case HttpSignatureParameterCreated:
@@ -325,7 +325,7 @@ func SignRequest(
 			hasCreatedParameter = true
 		case HttpSignatureParameterExpires:
 			if auth.SignatureMaxValidity.Nanoseconds() == 0 {
-				return fmt.Errorf("Cannot set '(expires)' signature parameter. SignatureMaxValidity is not configured.")
+				return fmt.Errorf("cannot set '(expires)' signature parameter. SignatureMaxValidity is not configured")
 			}
 			value = fmt.Sprintf("%.3f", expiresUnix)
 			hasExpiresParameter = true
@@ -361,7 +361,7 @@ func SignRequest(
 			if v, ok = r.Header[canonicalHeader]; !ok {
 				// If a header specified in the headers parameter cannot be matched with
 				// a provided header in the message, the implementation MUST produce an error.
-				return fmt.Errorf("Header '%s' does not exist in the request", canonicalHeader)
+				return fmt.Errorf("header '%s' does not exist in the request", canonicalHeader)
 			}
 			// If there are multiple instances of the same header field, all
 			// header field values associated with the header field MUST be
@@ -376,7 +376,7 @@ func SignRequest(
 		fmt.Fprintf(&sb, "%s: %s", header, value)
 	}
 	if expiresUnix != 0 && !hasExpiresParameter {
-		return fmt.Errorf("SignatureMaxValidity is specified, but '(expired)' parameter is not present")
+		return fmt.Errorf("signatureMaxValidity is specified, but '(expired)' parameter is not present")
 	}
 	msg := []byte(sb.String())
 	msgHash := h.New()
@@ -394,14 +394,14 @@ func SignRequest(
 		case "", HttpSigningAlgorithmRsaPSS:
 			signature, err = rsa.SignPSS(rand.Reader, key, h, d, nil)
 		default:
-			return fmt.Errorf("Unsupported signing algorithm: '%s'", auth.SigningAlgorithm)
+			return fmt.Errorf("unsupported signing algorithm: '%s'", auth.SigningAlgorithm)
 		}
 	case *ecdsa.PrivateKey:
 		signature, err = key.Sign(rand.Reader, d, h)
 	case ed25519.PrivateKey: // requires go 1.13
 	  signature, err = key.Sign(rand.Reader, msg, crypto.Hash(0))
 	default:
-		return fmt.Errorf("Unsupported private key")
+		return fmt.Errorf("unsupported private key")
 	}
 	if err != nil {
 		return err

samples/client/petstore/go/go-petstore/client.go

@@ -135,7 +135,7 @@ func typeCheckParameter(obj interface{}, expected string, name string) error {
 
 	// Check the type is as expected.
 	if reflect.TypeOf(obj).String() != expected {
-		return fmt.Errorf("Expected %s to be of type %s but received %s.", name, expected, reflect.TypeOf(obj).String())
+		return fmt.Errorf("expected %s to be of type %s but received %s", name, expected, reflect.TypeOf(obj).String())
 	}
 	return nil
 }
@@ -474,7 +474,7 @@ func setBody(body interface{}, contentType string) (bodyBuf *bytes.Buffer, err e
 	}
 
 	if bodyBuf.Len() == 0 {
-		err = fmt.Errorf("Invalid body type %s\n", contentType)
+		err = fmt.Errorf("invalid body type %s\n", contentType)
 		return nil, err
 	}
 	return bodyBuf, nil

samples/client/petstore/go/go-petstore/configuration.go

@@ -123,7 +123,7 @@ func (c *Configuration) AddDefaultHeader(key string, value string) {
 // URL formats template on a index using given variables
 func (sc ServerConfigurations) URL(index int, variables map[string]string) (string, error) {
 	if index < 0 || len(sc) <= index {
-		return "", fmt.Errorf("Index %v out of range %v", index, len(sc)-1)
+		return "", fmt.Errorf("index %v out of range %v", index, len(sc)-1)
 	}
 	server := sc[index]
 	url := server.URL
@@ -138,7 +138,7 @@ func (sc ServerConfigurations) URL(index int, variables map[string]string) (stri
 				}
 			}
 			if !found {
-				return "", fmt.Errorf("The variable %s in the server URL has invalid value %v. Must be %v", name, value, variable.EnumValues)
+				return "", fmt.Errorf("the variable %s in the server URL has invalid value %v. Must be %v", name, value, variable.EnumValues)
 			}
 			url = strings.Replace(url, "{"+name+"}", value, -1)
 		} else {

samples/openapi3/client/extensions/x-auth-id-alias/go-experimental/client.go

@@ -120,7 +120,7 @@ func typeCheckParameter(obj interface{}, expected string, name string) error {
 
 	// Check the type is as expected.
 	if reflect.TypeOf(obj).String() != expected {
-		return fmt.Errorf("Expected %s to be of type %s but received %s.", name, expected, reflect.TypeOf(obj).String())
+		return fmt.Errorf("expected %s to be of type %s but received %s", name, expected, reflect.TypeOf(obj).String())
 	}
 	return nil
 }
@@ -459,7 +459,7 @@ func setBody(body interface{}, contentType string) (bodyBuf *bytes.Buffer, err e
 	}
 
 	if bodyBuf.Len() == 0 {
-		err = fmt.Errorf("Invalid body type %s\n", contentType)
+		err = fmt.Errorf("invalid body type %s\n", contentType)
 		return nil, err
 	}
 	return bodyBuf, nil

samples/openapi3/client/extensions/x-auth-id-alias/go-experimental/configuration.go

@@ -156,7 +156,7 @@ func (c *Configuration) AddDefaultHeader(key string, value string) {
 // URL formats template on a index using given variables
 func (sc ServerConfigurations) URL(index int, variables map[string]string) (string, error) {
 	if index < 0 || len(sc) <= index {
-		return "", fmt.Errorf("Index %v out of range %v", index, len(sc)-1)
+		return "", fmt.Errorf("index %v out of range %v", index, len(sc)-1)
 	}
 	server := sc[index]
 	url := server.URL
@@ -171,7 +171,7 @@ func (sc ServerConfigurations) URL(index int, variables map[string]string) (stri
 				}
 			}
 			if !found {
-				return "", fmt.Errorf("The variable %s in the server URL has invalid value %v. Must be %v", name, value, variable.EnumValues)
+				return "", fmt.Errorf("the variable %s in the server URL has invalid value %v. Must be %v", name, value, variable.EnumValues)
 			}
 			url = strings.Replace(url, "{"+name+"}", value, -1)
 		} else {

samples/openapi3/client/petstore/go/go-petstore/client.go

@@ -138,7 +138,7 @@ func typeCheckParameter(obj interface{}, expected string, name string) error {
 
 	// Check the type is as expected.
 	if reflect.TypeOf(obj).String() != expected {
-		return fmt.Errorf("Expected %s to be of type %s but received %s.", name, expected, reflect.TypeOf(obj).String())
+		return fmt.Errorf("expected %s to be of type %s but received %s", name, expected, reflect.TypeOf(obj).String())
 	}
 	return nil
 }
@@ -487,7 +487,7 @@ func setBody(body interface{}, contentType string) (bodyBuf *bytes.Buffer, err e
 	}
 
 	if bodyBuf.Len() == 0 {
-		err = fmt.Errorf("Invalid body type %s\n", contentType)
+		err = fmt.Errorf("invalid body type %s\n", contentType)
 		return nil, err
 	}
 	return bodyBuf, nil

samples/openapi3/client/petstore/go/go-petstore/configuration.go

@@ -180,7 +180,7 @@ func (c *Configuration) AddDefaultHeader(key string, value string) {
 // URL formats template on a index using given variables
 func (sc ServerConfigurations) URL(index int, variables map[string]string) (string, error) {
 	if index < 0 || len(sc) <= index {
-		return "", fmt.Errorf("Index %v out of range %v", index, len(sc)-1)
+		return "", fmt.Errorf("index %v out of range %v", index, len(sc)-1)
 	}
 	server := sc[index]
 	url := server.URL
@@ -195,7 +195,7 @@ func (sc ServerConfigurations) URL(index int, variables map[string]string) (stri
 				}
 			}
 			if !found {
-				return "", fmt.Errorf("The variable %s in the server URL has invalid value %v. Must be %v", name, value, variable.EnumValues)
+				return "", fmt.Errorf("the variable %s in the server URL has invalid value %v. Must be %v", name, value, variable.EnumValues)
 			}
 			url = strings.Replace(url, "{"+name+"}", value, -1)
 		} else {

samples/openapi3/client/petstore/go/go-petstore/model_fruit.go

@@ -71,11 +71,11 @@ func (dst *Fruit) UnmarshalJSON(data []byte) error {
 		dst.Apple = nil
 		dst.Banana = nil
 
-		return fmt.Errorf("Data matches more than one schema in oneOf(Fruit)")
+		return fmt.Errorf("data matches more than one schema in oneOf(Fruit)")
 	} else if match == 1 {
 		return nil // exactly one match
 	} else { // no match
-		return fmt.Errorf("Data failed to match schemas in oneOf(Fruit)")
+		return fmt.Errorf("data failed to match schemas in oneOf(Fruit)")
 	}
 }
 

samples/openapi3/client/petstore/go/go-petstore/model_fruit_req.go

@@ -71,11 +71,11 @@ func (dst *FruitReq) UnmarshalJSON(data []byte) error {
 		dst.AppleReq = nil
 		dst.BananaReq = nil
 
-		return fmt.Errorf("Data matches more than one schema in oneOf(FruitReq)")
+		return fmt.Errorf("data matches more than one schema in oneOf(FruitReq)")
 	} else if match == 1 {
 		return nil // exactly one match
 	} else { // no match
-		return fmt.Errorf("Data failed to match schemas in oneOf(FruitReq)")
+		return fmt.Errorf("data failed to match schemas in oneOf(FruitReq)")
 	}
 }
 

samples/openapi3/client/petstore/go/go-petstore/model_gm_fruit.go

@@ -50,7 +50,7 @@ func (dst *GmFruit) UnmarshalJSON(data []byte) error {
 		dst.Banana = nil
 	}
 
-	return fmt.Errorf("Data failed to match schemas in anyOf(GmFruit)")
+	return fmt.Errorf("data failed to match schemas in anyOf(GmFruit)")
 }
 
 // Marshal data from the first non-nil pointers in the struct to JSON

samples/openapi3/client/petstore/go/go-petstore/model_mammal.go

@@ -71,11 +71,11 @@ func (dst *Mammal) UnmarshalJSON(data []byte) error {
 		dst.Whale = nil
 		dst.Zebra = nil
 
-		return fmt.Errorf("Data matches more than one schema in oneOf(Mammal)")
+		return fmt.Errorf("data matches more than one schema in oneOf(Mammal)")
 	} else if match == 1 {
 		return nil // exactly one match
 	} else { // no match
-		return fmt.Errorf("Data failed to match schemas in oneOf(Mammal)")
+		return fmt.Errorf("data failed to match schemas in oneOf(Mammal)")
 	}
 }
 

samples/openapi3/client/petstore/go/go-petstore/model_one_of_primitive_type.go

@@ -93,11 +93,11 @@ func (dst *OneOfPrimitiveType) UnmarshalJSON(data []byte) error {
 		dst.ArrayOfString = nil
 		dst.Int32 = nil
 
-		return fmt.Errorf("Data matches more than one schema in oneOf(OneOfPrimitiveType)")
+		return fmt.Errorf("data matches more than one schema in oneOf(OneOfPrimitiveType)")
 	} else if match == 1 {
 		return nil // exactly one match
 	} else { // no match
-		return fmt.Errorf("Data failed to match schemas in oneOf(OneOfPrimitiveType)")
+		return fmt.Errorf("data failed to match schemas in oneOf(OneOfPrimitiveType)")
 	}
 }
 

samples/openapi3/client/petstore/go/go-petstore/signing.go

@@ -135,26 +135,26 @@ func (h *HttpSignatureAuth) SetPrivateKey(privateKey string) error {
 // are invalid.
 func (h *HttpSignatureAuth) ContextWithValue(ctx context.Context) (context.Context, error) {
 	if h.KeyId == "" {
-		return nil, fmt.Errorf("Key ID must be specified")
+		return nil, fmt.Errorf("key ID must be specified")
 	}
 	if h.PrivateKeyPath == "" && h.privateKey == nil {
-		return nil, fmt.Errorf("Private key path must be specified")
+		return nil, fmt.Errorf("private key path must be specified")
 	}
 	if _, ok := supportedSigningSchemes[h.SigningScheme]; !ok {
-		return nil, fmt.Errorf("Invalid signing scheme: '%v'", h.SigningScheme)
+		return nil, fmt.Errorf("invalid signing scheme: '%v'", h.SigningScheme)
 	}
 	m := make(map[string]bool)
 	for _, h := range h.SignedHeaders {
 		if strings.EqualFold(h, HttpHeaderAuthorization) {
-			return nil, fmt.Errorf("Signed headers cannot include the 'Authorization' header")
+			return nil, fmt.Errorf("signed headers cannot include the 'Authorization' header")
 		}
 		m[h] = true
 	}
 	if len(m) != len(h.SignedHeaders) {
-		return nil, fmt.Errorf("List of signed headers cannot have duplicate names")
+		return nil, fmt.Errorf("list of signed headers cannot have duplicate names")
 	}
 	if h.SignatureMaxValidity < 0 {
-		return nil, fmt.Errorf("Signature max validity must be a positive value")
+		return nil, fmt.Errorf("signature max validity must be a positive value")
 	}
 	if err := h.loadPrivateKey(); err != nil {
 		return nil, err
@@ -177,7 +177,7 @@ func (h *HttpSignatureAuth) GetPublicKey() (crypto.PublicKey, error) {
 	default:
 		// Do not change '%T' to anything else such as '%v'!
 		// The value of the private key must not be returned.
-		return nil, fmt.Errorf("Unsupported key: %T", h.privateKey)
+		return nil, fmt.Errorf("unsupported key: %T", h.privateKey)
 	}
 }
 
@@ -190,7 +190,7 @@ func (h *HttpSignatureAuth) loadPrivateKey() (err error) {
 	var file *os.File
 	file, err = os.Open(h.PrivateKeyPath)
 	if err != nil {
-		return fmt.Errorf("Cannot load private key '%s'. Error: %v", h.PrivateKeyPath, err)
+		return fmt.Errorf("cannot load private key '%s'. Error: %v", h.PrivateKeyPath, err)
 	}
 	defer func() {
 		err = file.Close()
@@ -208,7 +208,7 @@ func (h *HttpSignatureAuth) parsePrivateKey(priv []byte) error {
 	pemBlock, _ := pem.Decode(priv)
 	if pemBlock == nil {
 		// No PEM data has been found.
-		return fmt.Errorf("File '%s' does not contain PEM data", h.PrivateKeyPath)
+		return fmt.Errorf("file '%s' does not contain PEM data", h.PrivateKeyPath)
 	}
 	var privKey []byte
 	var err error
@@ -234,7 +234,7 @@ func (h *HttpSignatureAuth) parsePrivateKey(priv []byte) error {
 			return err
 		}
 	default:
-		return fmt.Errorf("Key '%s' is not supported", pemBlock.Type)
+		return fmt.Errorf("key '%s' is not supported", pemBlock.Type)
 	}
 	return nil
 }
@@ -257,7 +257,7 @@ func SignRequest(
 	auth HttpSignatureAuth) error {
 
 	if auth.privateKey == nil {
-		return fmt.Errorf("Private key is not set")
+		return fmt.Errorf("private key is not set")
 	}
 	now := time.Now()
 	date := now.UTC().Format(http.TimeFormat)
@@ -271,7 +271,7 @@ func SignRequest(
 	var expiresUnix float64
 
 	if auth.SignatureMaxValidity < 0 {
-		return fmt.Errorf("Signature validity must be a positive value")
+		return fmt.Errorf("signature validity must be a positive value")
 	}
 	if auth.SignatureMaxValidity > 0 {
 		e := now.Add(auth.SignatureMaxValidity)
@@ -287,10 +287,10 @@ func SignRequest(
 		h = crypto.SHA256
 		prefix = "SHA-256="
 	default:
-		return fmt.Errorf("Unsupported signature scheme: %v", auth.SigningScheme)
+		return fmt.Errorf("unsupported signature scheme: %v", auth.SigningScheme)
 	}
 	if !h.Available() {
-		return fmt.Errorf("Hash '%v' is not available", h)
+		return fmt.Errorf("hash '%v' is not available", h)
 	}
 
 	// Build the "(request-target)" signature header.
@@ -317,7 +317,7 @@ func SignRequest(
 		m[h] = true
 	}
 	if len(m) != len(signedHeaders) {
-		return fmt.Errorf("List of signed headers must not have any duplicates")
+		return fmt.Errorf("list of signed headers must not have any duplicates")
 	}
 	hasCreatedParameter := false
 	hasExpiresParameter := false
@@ -326,7 +326,7 @@ func SignRequest(
 		var value string
 		switch header {
 		case strings.ToLower(HttpHeaderAuthorization):
-			return fmt.Errorf("Cannot include the 'Authorization' header as a signed header.")
+			return fmt.Errorf("cannot include the 'Authorization' header as a signed header")
 		case HttpSignatureParameterRequestTarget:
 			value = requestTarget
 		case HttpSignatureParameterCreated:
@@ -334,7 +334,7 @@ func SignRequest(
 			hasCreatedParameter = true
 		case HttpSignatureParameterExpires:
 			if auth.SignatureMaxValidity.Nanoseconds() == 0 {
-				return fmt.Errorf("Cannot set '(expires)' signature parameter. SignatureMaxValidity is not configured.")
+				return fmt.Errorf("cannot set '(expires)' signature parameter. SignatureMaxValidity is not configured")
 			}
 			value = fmt.Sprintf("%.3f", expiresUnix)
 			hasExpiresParameter = true
@@ -370,7 +370,7 @@ func SignRequest(
 			if v, ok = r.Header[canonicalHeader]; !ok {
 				// If a header specified in the headers parameter cannot be matched with
 				// a provided header in the message, the implementation MUST produce an error.
-				return fmt.Errorf("Header '%s' does not exist in the request", canonicalHeader)
+				return fmt.Errorf("header '%s' does not exist in the request", canonicalHeader)
 			}
 			// If there are multiple instances of the same header field, all
 			// header field values associated with the header field MUST be
@@ -385,7 +385,7 @@ func SignRequest(
 		fmt.Fprintf(&sb, "%s: %s", header, value)
 	}
 	if expiresUnix != 0 && !hasExpiresParameter {
-		return fmt.Errorf("SignatureMaxValidity is specified, but '(expired)' parameter is not present")
+		return fmt.Errorf("signatureMaxValidity is specified, but '(expired)' parameter is not present")
 	}
 	msg := []byte(sb.String())
 	msgHash := h.New()
@@ -403,14 +403,14 @@ func SignRequest(
 		case "", HttpSigningAlgorithmRsaPSS:
 			signature, err = rsa.SignPSS(rand.Reader, key, h, d, nil)
 		default:
-			return fmt.Errorf("Unsupported signing algorithm: '%s'", auth.SigningAlgorithm)
+			return fmt.Errorf("unsupported signing algorithm: '%s'", auth.SigningAlgorithm)
 		}
 	case *ecdsa.PrivateKey:
 		signature, err = key.Sign(rand.Reader, d, h)
 	case ed25519.PrivateKey: // requires go 1.13
 	  signature, err = key.Sign(rand.Reader, msg, crypto.Hash(0))
 	default:
-		return fmt.Errorf("Unsupported private key")
+		return fmt.Errorf("unsupported private key")
 	}
 	if err != nil {
 		return err

samples/openapi3/client/petstore/go/http_signature_test.go

@@ -650,7 +650,7 @@ func TestInvalidHttpSignatureConfiguration(t *testing.T) {
 
 	authConfig = sw.HttpSignatureAuth{}
 	_, err = authConfig.ContextWithValue(context.Background())
-	if err == nil || !strings.Contains(err.Error(), "Key ID must be specified") {
+	if err == nil || !strings.Contains(err.Error(), "key ID must be specified") {
 		t.Fatalf("Invalid configuration: %v", err)
 	}
 
@@ -658,7 +658,7 @@ func TestInvalidHttpSignatureConfiguration(t *testing.T) {
 		KeyId: "my-key-id",
 	}
 	_, err = authConfig.ContextWithValue(context.Background())
-	if err == nil || !strings.Contains(err.Error(), "Private key path must be specified") {
+	if err == nil || !strings.Contains(err.Error(), "private key path must be specified") {
 		t.Fatalf("Invalid configuration: %v", err)
 	}
 
@@ -667,7 +667,7 @@ func TestInvalidHttpSignatureConfiguration(t *testing.T) {
 		PrivateKeyPath: "test.pem",
 	}
 	_, err = authConfig.ContextWithValue(context.Background())
-	if err == nil || !strings.Contains(err.Error(), "Invalid signing scheme") {
+	if err == nil || !strings.Contains(err.Error(), "invalid signing scheme") {
 		t.Fatalf("Invalid configuration: %v", err)
 	}
 
@@ -677,7 +677,7 @@ func TestInvalidHttpSignatureConfiguration(t *testing.T) {
 		SigningScheme:  "garbage",
 	}
 	_, err = authConfig.ContextWithValue(context.Background())
-	if err == nil || !strings.Contains(err.Error(), "Invalid signing scheme") {
+	if err == nil || !strings.Contains(err.Error(), "invalid signing scheme") {
 		t.Fatalf("Invalid configuration: %v", err)
 	}
 
@@ -699,7 +699,7 @@ func TestInvalidHttpSignatureConfiguration(t *testing.T) {
 		SignedHeaders:  []string{"foo", "bar", "Authorization"},
 	}
 	_, err = authConfig.ContextWithValue(context.Background())
-	if err == nil || !strings.Contains(err.Error(), "Signed headers cannot include the 'Authorization' header") {
+	if err == nil || !strings.Contains(err.Error(), "signed headers cannot include the 'Authorization' header") {
 		t.Fatalf("Invalid configuration: %v", err)
 	}
 
@@ -711,7 +711,7 @@ func TestInvalidHttpSignatureConfiguration(t *testing.T) {
 		SignatureMaxValidity: -7 * time.Minute,
 	}
 	_, err = authConfig.ContextWithValue(context.Background())
-	if err == nil || !strings.Contains(err.Error(), "Signature max validity must be a positive value") {
+	if err == nil || !strings.Contains(err.Error(), "signature max validity must be a positive value") {
 		t.Fatalf("Invalid configuration: %v", err)
 	}
 }