Incorporate minor updates from the standard library

bool_test.go

@@ -5,8 +5,8 @@
 package pflag
 
 import (
-	"bytes"
 	"strconv"
+	"strings"
 	"testing"
 )
 
@@ -155,7 +155,7 @@ func TestImplicitFalse(t *testing.T) {
 func TestInvalidValue(t *testing.T) {
 	var tristate triStateValue
 	f := setUpFlagSet(&tristate)
-	var buf bytes.Buffer
+	var buf strings.Builder
 	f.SetOutput(&buf)
 	err := f.Parse([]string{"--tristate=invalid"})
 	if err == nil {

bytes.go

@@ -46,7 +46,7 @@ func bytesHexConv(sval string) (interface{}, error) {
 		return bin, nil
 	}
 
-	return nil, fmt.Errorf("invalid string being converted to Bytes: %s %s", sval, err)
+	return nil, fmt.Errorf("invalid string being converted to Bytes: %s %w", sval, err)
 }
 
 // GetBytesHex return the []byte value of a flag with the given name
@@ -146,7 +146,7 @@ func bytesBase64ValueConv(sval string) (interface{}, error) {
 		return bin, nil
 	}
 
-	return nil, fmt.Errorf("invalid string being converted to Bytes: %s %s", sval, err)
+	return nil, fmt.Errorf("invalid string being converted to Bytes: %s %w", sval, err)
 }
 
 // GetBytesBase64 return the []byte value of a flag with the given name

count.go

@@ -13,7 +13,7 @@ func newCountValue(val int, p *int) *countValue {
 func (i *countValue) Set(s string) error {
 	// "+1" means that no specific value was passed, so increment
 	if s == "+1" {
-		*i = countValue(*i + 1)
+		*i++
 		return nil
 	}
 	v, err := strconv.ParseInt(s, 0, 0)

duration_slice.go

@@ -1,7 +1,6 @@
 package pflag
 
 import (
-	"fmt"
 	"strings"
 	"time"
 )
@@ -46,7 +45,7 @@ func (s *durationSliceValue) Type() string {
 func (s *durationSliceValue) String() string {
 	out := make([]string, len(*s.value))
 	for i, d := range *s.value {
-		out[i] = fmt.Sprintf("%s", d)
+		out[i] = d.String()
 	}
 	return "[" + strings.Join(out, ",") + "]"
 }
@@ -56,7 +55,7 @@ func (s *durationSliceValue) fromString(val string) (time.Duration, error) {
 }
 
 func (s *durationSliceValue) toString(val time.Duration) string {
-	return fmt.Sprintf("%s", val)
+	return val.String()
 }
 
 func (s *durationSliceValue) Append(val string) error {

flag.go

@@ -99,7 +99,6 @@ flag set.
 package pflag
 
 import (
-	"bytes"
 	"errors"
 	goflag "flag"
 	"fmt"
@@ -169,17 +168,17 @@ type FlagSet struct {
 
 // A Flag represents the state of a flag.
 type Flag struct {
+	Value               Value               // value as set
+	Annotations         map[string][]string // used by cobra.Command bash autocomple code
 	Name                string              // name as it appears on command line
 	Shorthand           string              // one-letter abbreviated flag
 	Usage               string              // help message
-	Value               Value               // value as set
 	DefValue            string              // default value (as text); for usage message
-	Changed             bool                // If the user set the value (or if left to default)
 	NoOptDefVal         string              // default value (as text); if the flag is on the command line without any options
 	Deprecated          string              // If this flag is deprecated, this string is the new or now thing to use
-	Hidden              bool                // used by cobra.Command to allow flags to be hidden from help/usage text
 	ShorthandDeprecated string              // If the shorthand of this flag is deprecated, this string is the new or now thing to use
-	Annotations         map[string][]string // used by cobra.Command bash autocomple code
+	Changed             bool                // If the user set the value (or if left to default)
+	Hidden              bool                // used by cobra.Command to allow flags to be hidden from help/usage text
 }
 
 // Value is the interface to the dynamic value stored in a flag.
@@ -365,7 +364,7 @@ func (f *FlagSet) ShorthandLookup(name string) *Flag {
 	}
 	if len(name) > 1 {
 		msg := fmt.Sprintf("can not look up shorthand which is more than one ASCII character: %q", name)
-		fmt.Fprintf(f.Output(), msg)
+		fmt.Fprint(f.Output(), msg)
 		panic(msg)
 	}
 	c := name[0]
@@ -475,7 +474,7 @@ func (f *FlagSet) Set(name, value string) error {
 		} else {
 			flagName = fmt.Sprintf("--%s", flag.Name)
 		}
-		return fmt.Errorf("invalid argument %q for %q flag: %v", value, flagName, err)
+		return fmt.Errorf("invalid argument %q for %q flag: %w", value, flagName, err)
 	}
 
 	if !flag.Changed {
@@ -634,7 +633,7 @@ func wrapN(i, slop int, s string) (string, string) {
 // caller). Pass `w` == 0 to do no wrapping
 func wrap(i, w int, s string) string {
 	if w == 0 {
-		return strings.Replace(s, "\n", "\n"+strings.Repeat(" ", i), -1)
+		return strings.ReplaceAll(s, "\n", "\n"+strings.Repeat(" ", i))
 	}
 
 	// space between indent i and end of line width w into which
@@ -652,7 +651,7 @@ func wrap(i, w int, s string) string {
 	}
 	// If still not enough space then don't even try to wrap.
 	if wrap < 24 {
-		return strings.Replace(s, "\n", r, -1)
+		return strings.ReplaceAll(s, "\n", r)
 	}
 
 	// Try to avoid short orphan words on the final line, by
@@ -664,35 +663,33 @@ func wrap(i, w int, s string) string {
 	// Handle first line, which is indented by the caller (or the
 	// special case above)
 	l, s = wrapN(wrap, slop, s)
-	r = r + strings.Replace(l, "\n", "\n"+strings.Repeat(" ", i), -1)
+	r = r + strings.ReplaceAll(l, "\n", "\n"+strings.Repeat(" ", i))
 
 	// Now wrap the rest
 	for s != "" {
 		var t string
 
 		t, s = wrapN(wrap, slop, s)
-		r = r + "\n" + strings.Repeat(" ", i) + strings.Replace(t, "\n", "\n"+strings.Repeat(" ", i), -1)
+		r = r + "\n" + strings.Repeat(" ", i) + strings.ReplaceAll(t, "\n", "\n"+strings.Repeat(" ", i))
 	}
 
 	return r
-
 }
 
 // FlagUsagesWrapped returns a string containing the usage information
 // for all flags in the FlagSet. Wrapped to `cols` columns (0 for no
 // wrapping)
 func (f *FlagSet) FlagUsagesWrapped(cols int) string {
-	buf := new(bytes.Buffer)
-
-	lines := make([]string, 0, len(f.formal))
-
-	maxlen := 0
+	var (
+		max, maxlen int
+		lines       = make([]string, 0, len(f.formal))
+	)
 	f.VisitAll(func(flag *Flag) {
 		if flag.Hidden {
 			return
 		}
 
-		line := ""
+		var line string
 		if flag.Shorthand != "" && flag.ShorthandDeprecated == "" {
 			line = fmt.Sprintf("  -%s, --%s", flag.Shorthand, flag.Name)
 		} else {
@@ -740,8 +737,11 @@ func (f *FlagSet) FlagUsagesWrapped(cols int) string {
 		}
 
 		lines = append(lines, line)
+		max += len(line)
 	})
 
+	buf := new(strings.Builder)
+	buf.Grow(max)
 	for _, line := range lines {
 		sidx := strings.Index(line, "\x00")
 		spacing := strings.Repeat(" ", maxlen-sidx)
@@ -867,7 +867,7 @@ func (f *FlagSet) AddFlag(flag *Flag) {
 	}
 	if len(flag.Shorthand) > 1 {
 		msg := fmt.Sprintf("%q shorthand is more than one ASCII character", flag.Shorthand)
-		fmt.Fprintf(f.Output(), msg)
+		fmt.Fprint(f.Output(), msg)
 		panic(msg)
 	}
 	if f.shorthands == nil {
@@ -877,7 +877,7 @@ func (f *FlagSet) AddFlag(flag *Flag) {
 	used, alreadyThere := f.shorthands[c]
 	if alreadyThere {
 		msg := fmt.Sprintf("unable to redefine %q shorthand in %q flagset: it's already used for %q flag", c, f.name, used.Name)
-		fmt.Fprintf(f.Output(), msg)
+		fmt.Fprint(f.Output(), msg)
 		panic(msg)
 	}
 	f.shorthands[c] = flag
@@ -1135,10 +1135,6 @@ func (f *FlagSet) Parse(arguments []string) error {
 	}
 	f.parsed = true
 
-	if len(arguments) < 0 {
-		return nil
-	}
-
 	f.args = make([]string, 0, len(arguments))
 
 	set := func(flag *Flag, value string) error {

flag_test.go

@@ -5,7 +5,6 @@
 package pflag
 
 import (
-	"bytes"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -629,7 +628,7 @@ func TestChangedHelper(t *testing.T) {
 func replaceSeparators(name string, from []string, to string) string {
 	result := name
 	for _, sep := range from {
-		result = strings.Replace(result, sep, to, -1)
+		result = strings.ReplaceAll(result, sep, to)
 	}
 	// Type convert to indicate normalization has been done.
 	return result
@@ -855,7 +854,7 @@ func TestUserDefined(t *testing.T) {
 
 func TestSetOutput(t *testing.T) {
 	var flags FlagSet
-	var buf bytes.Buffer
+	var buf strings.Builder
 	flags.SetOutput(&buf)
 	flags.Init("test", ContinueOnError)
 	flags.Parse([]string{"--unknown"})
@@ -866,7 +865,7 @@ func TestSetOutput(t *testing.T) {
 
 func TestOutput(t *testing.T) {
 	var flags FlagSet
-	var buf bytes.Buffer
+	var buf strings.Builder
 	expect := "an example string"
 	flags.SetOutput(&buf)
 	fmt.Fprint(flags.Output(), expect)
@@ -1001,7 +1000,7 @@ func getDeprecatedFlagSet() *FlagSet {
 func TestDeprecatedFlagInDocs(t *testing.T) {
 	f := getDeprecatedFlagSet()
 
-	out := new(bytes.Buffer)
+	out := new(strings.Builder)
 	f.SetOutput(out)
 	f.PrintDefaults()
 
@@ -1018,7 +1017,7 @@ func TestUnHiddenDeprecatedFlagInDocs(t *testing.T) {
 	}
 	flg.Hidden = false
 
-	out := new(bytes.Buffer)
+	out := new(strings.Builder)
 	f.SetOutput(out)
 	f.PrintDefaults()
 
@@ -1037,7 +1036,7 @@ func TestDeprecatedFlagShorthandInDocs(t *testing.T) {
 	f.BoolP(name, "n", true, "always true")
 	f.MarkShorthandDeprecated("noshorthandflag", fmt.Sprintf("use --%s instead", name))
 
-	out := new(bytes.Buffer)
+	out := new(strings.Builder)
 	f.SetOutput(out)
 	f.PrintDefaults()
 
@@ -1056,7 +1055,7 @@ func parseReturnStderr(t *testing.T, f *FlagSet, args []string) (string, error)
 	outC := make(chan string)
 	// copy the output in a separate goroutine so printing can't block indefinitely
 	go func() {
-		var buf bytes.Buffer
+		var buf strings.Builder
 		io.Copy(&buf, r)
 		outC <- buf.String()
 	}()
@@ -1140,7 +1139,7 @@ func TestHiddenFlagInUsage(t *testing.T) {
 	f.Bool("secretFlag", true, "shhh")
 	f.MarkHidden("secretFlag")
 
-	out := new(bytes.Buffer)
+	out := new(strings.Builder)
 	f.SetOutput(out)
 	f.PrintDefaults()
 
@@ -1204,7 +1203,7 @@ func (cv *customValue) Type() string { return "custom" }
 
 func TestPrintDefaults(t *testing.T) {
 	fs := NewFlagSet("print defaults test", ContinueOnError)
-	var buf bytes.Buffer
+	var buf strings.Builder
 	fs.SetOutput(&buf)
 	fs.Bool("A", false, "for bootstrapping, allow 'any' type")
 	fs.Bool("Alongflagname", false, "disable bounds checking")
@@ -1238,8 +1237,6 @@ func TestPrintDefaults(t *testing.T) {
 	fs.PrintDefaults()
 	got := buf.String()
 	if got != defaultOutput {
-		fmt.Println("\n" + got)
-		fmt.Println("\n" + defaultOutput)
 		t.Errorf("got %q want %q\n", got, defaultOutput)
 	}
 }

ip.go

@@ -32,8 +32,7 @@ func (i *ipValue) Type() string {
 }
 
 func ipConv(sval string) (interface{}, error) {
-	ip := net.ParseIP(sval)
-	if ip != nil {
+	if ip := net.ParseIP(sval); ip != nil {
 		return ip, nil
 	}
 	return nil, fmt.Errorf("invalid string being converted to IP address: %s", sval)

ip_slice.go

@@ -72,31 +72,24 @@ func (s *ipSliceValue) String() string {
 	return "[" + out + "]"
 }
 
-func (s *ipSliceValue) fromString(val string) (net.IP, error) {
-	return net.ParseIP(strings.TrimSpace(val)), nil
+func (s *ipSliceValue) fromString(val string) net.IP {
+	return net.ParseIP(strings.TrimSpace(val))
 }
 
 func (s *ipSliceValue) toString(val net.IP) string {
 	return val.String()
 }
 
 func (s *ipSliceValue) Append(val string) error {
-	i, err := s.fromString(val)
-	if err != nil {
-		return err
-	}
+	i := s.fromString(val)
 	*s.value = append(*s.value, i)
 	return nil
 }
 
 func (s *ipSliceValue) Replace(val []string) error {
 	out := make([]net.IP, len(val))
 	for i, d := range val {
-		var err error
-		out[i], err = s.fromString(d)
-		if err != nil {
-			return err
-		}
+		out[i] = s.fromString(d)
 	}
 	*s.value = out
 	return nil

printusage_test.go

@@ -1,8 +1,8 @@
 package pflag
 
 import (
-	"bytes"
 	"io"
+	"strings"
 	"testing"
 )
 
@@ -25,7 +25,7 @@ func setUpPFlagSet(buf io.Writer) *FlagSet {
 }
 
 func TestPrintUsage(t *testing.T) {
-	buf := bytes.Buffer{}
+	var buf strings.Builder
 	f := setUpPFlagSet(&buf)
 	f.PrintDefaults()
 	res := buf.String()
@@ -65,7 +65,7 @@ const expectedOutput2 = `      --long-form                    Some description
 `
 
 func TestPrintUsage_2(t *testing.T) {
-	buf := bytes.Buffer{}
+	var buf strings.Builder
 	f := setUpPFlagSet2(&buf)
 	res := f.FlagUsagesWrapped(80)
 	if res != expectedOutput2 {