Merge commit '5ac0710' into v3-porting

app_test.go

@@ -2622,19 +2622,6 @@ func TestSetupInitializesOnlyNilWriters(t *testing.T) {
 	}
 }
 
-type stringGeneric struct {
-	value string
-}
-
-func (s *stringGeneric) Set(value string) error {
-	s.value = value
-	return nil
-}
-
-func (s *stringGeneric) String() string {
-	return s.value
-}
-
 func TestFlagAction(t *testing.T) {
 	stringFlag := &StringFlag{
 		Name: "f_string",

cmd/urfave-cli-genflags/generated.gotmpl

@@ -22,6 +22,8 @@ type {{.TypeName}} struct {
   Aliases []string
   EnvVars []string
 
+  defaultValue {{if .ValuePointer}}*{{end}}{{.GoType}}
+  
   {{range .StructFields}}
   {{.Name}} {{if .Pointer}}*{{end}}{{.Type}}
   {{end}}

flag_bool.go

@@ -69,7 +69,7 @@ func (f *BoolFlag) GetDefaultText() string {
 	if f.DefaultText != "" {
 		return f.DefaultText
 	}
-	return fmt.Sprintf("%v", f.Value)
+	return fmt.Sprintf("%v", f.defaultValue)
 }
 
 // RunAction executes flag action if set
@@ -83,6 +83,9 @@ func (f *BoolFlag) RunAction(c *Context) error {
 
 // Apply populates the flag given the flag set and environment
 func (f *BoolFlag) Apply(set *flag.FlagSet) error {
+	// set default value so that environment wont be able to overwrite it
+	f.defaultValue = f.Value
+
 	if val, source, found := flagFromEnvOrFile(f.EnvVars, f.FilePath); found {
 		if val != "" {
 			valBool, err := strconv.ParseBool(val)

flag_duration.go

@@ -17,11 +17,14 @@ func (f *DurationFlag) GetDefaultText() string {
 	if f.DefaultText != "" {
 		return f.DefaultText
 	}
-	return f.GetValue()
+	return f.defaultValue.String()
 }
 
 // Apply populates the flag given the flag set and environment
 func (f *DurationFlag) Apply(set *flag.FlagSet) error {
+	// set default value so that environment wont be able to overwrite it
+	f.defaultValue = f.Value
+
 	if val, source, found := flagFromEnvOrFile(f.EnvVars, f.FilePath); found {
 		if val != "" {
 			valDuration, err := time.ParseDuration(val)

flag_generic.go

@@ -11,6 +11,19 @@ type Generic interface {
 	String() string
 }
 
+type stringGeneric struct {
+	value string
+}
+
+func (s *stringGeneric) Set(value string) error {
+	s.value = value
+	return nil
+}
+
+func (s *stringGeneric) String() string {
+	return s.value
+}
+
 // GetValue returns the flags value as string representation and an empty
 // string if the flag takes no value at all.
 func (f *GenericFlag) GetValue() string {
@@ -25,12 +38,20 @@ func (f *GenericFlag) GetDefaultText() string {
 	if f.DefaultText != "" {
 		return f.DefaultText
 	}
-	return f.GetValue()
+	if f.defaultValue != nil {
+		return f.defaultValue.String()
+	}
+	return ""
 }
 
 // Apply takes the flagset and calls Set on the generic flag with the value
 // provided by the user for parsing by the flag
 func (f *GenericFlag) Apply(set *flag.FlagSet) error {
+	// set default value so that environment wont be able to overwrite it
+	if f.Value != nil {
+		f.defaultValue = &stringGeneric{value: f.Value.String()}
+	}
+
 	if val, source, found := flagFromEnvOrFile(f.EnvVars, f.FilePath); found {
 		if val != "" {
 			if err := f.Value.Set(val); err != nil {

flag_int.go

@@ -17,11 +17,14 @@ func (f *IntFlag) GetDefaultText() string {
 	if f.DefaultText != "" {
 		return f.DefaultText
 	}
-	return f.GetValue()
+	return fmt.Sprintf("%d", f.defaultValue)
 }
 
 // Apply populates the flag given the flag set and environment
 func (f *IntFlag) Apply(set *flag.FlagSet) error {
+	// set default value so that environment wont be able to overwrite it
+	f.defaultValue = f.Value
+
 	if val, source, found := flagFromEnvOrFile(f.EnvVars, f.FilePath); found {
 		if val != "" {
 			valInt, err := strconv.ParseInt(val, f.Base, 64)

flag_int64.go

@@ -17,11 +17,14 @@ func (f *Int64Flag) GetDefaultText() string {
 	if f.DefaultText != "" {
 		return f.DefaultText
 	}
-	return f.GetValue()
+	return fmt.Sprintf("%d", f.defaultValue)
 }
 
 // Apply populates the flag given the flag set and environment
 func (f *Int64Flag) Apply(set *flag.FlagSet) error {
+	// set default value so that environment wont be able to overwrite it
+	f.defaultValue = f.Value
+
 	if val, source, found := flagFromEnvOrFile(f.EnvVars, f.FilePath); found {
 		if val != "" {
 			valInt, err := strconv.ParseInt(val, f.Base, 64)

flag_path.go

@@ -18,14 +18,17 @@ func (f *PathFlag) GetDefaultText() string {
 	if f.DefaultText != "" {
 		return f.DefaultText
 	}
-	if f.Value == "" {
-		return f.Value
+	if f.defaultValue == "" {
+		return f.defaultValue
 	}
-	return fmt.Sprintf("%q", f.Value)
+	return fmt.Sprintf("%q", f.defaultValue)
 }
 
 // Apply populates the flag given the flag set and environment
 func (f *PathFlag) Apply(set *flag.FlagSet) error {
+	// set default value so that environment wont be able to overwrite it
+	f.defaultValue = f.Value
+
 	if val, _, found := flagFromEnvOrFile(f.EnvVars, f.FilePath); found {
 		f.Value = val
 		f.HasBeenSet = true

flag_string.go

@@ -16,14 +16,17 @@ func (f *StringFlag) GetDefaultText() string {
 	if f.DefaultText != "" {
 		return f.DefaultText
 	}
-	if f.Value == "" {
-		return f.Value
+	if f.defaultValue == "" {
+		return f.defaultValue
 	}
-	return fmt.Sprintf("%q", f.Value)
+	return fmt.Sprintf("%q", f.defaultValue)
 }
 
 // Apply populates the flag given the flag set and environment
 func (f *StringFlag) Apply(set *flag.FlagSet) error {
+	// set default value so that environment wont be able to overwrite it
+	f.defaultValue = f.Value
+
 	if val, _, found := flagFromEnvOrFile(f.EnvVars, f.FilePath); found {
 		f.Value = val
 		f.HasBeenSet = true

flag_test.go

@@ -8,7 +8,6 @@ import (
 	"os"
 	"reflect"
 	"regexp"
-	"runtime"
 	"strings"
 	"testing"
 	"time"
@@ -477,6 +476,9 @@ var stringFlagTests = []struct {
 func TestStringFlagHelpOutput(t *testing.T) {
 	for _, test := range stringFlagTests {
 		fl := &StringFlag{Name: test.name, Aliases: test.aliases, Usage: test.usage, Value: test.value}
+		// create a tmp flagset
+		tfs := flag.NewFlagSet("test", 0)
+		fl.Apply(tfs)
 		output := fl.String()
 
 		if output != test.expected {
@@ -504,10 +506,7 @@ func TestStringFlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := &StringFlag{Name: test.name, Aliases: test.aliases, Value: test.value, EnvVars: []string{"APP_FOO"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_FOO]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_FOO%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_FOO"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%s does not end with"+expectedSuffix, output)
 		}
@@ -575,6 +574,11 @@ var pathFlagTests = []struct {
 func TestPathFlagHelpOutput(t *testing.T) {
 	for _, test := range pathFlagTests {
 		fl := &PathFlag{Name: test.name, Aliases: test.aliases, Usage: test.usage, Value: test.value}
+
+		// create a temporary flag set to apply
+		tfs := flag.NewFlagSet("test", 0)
+		fl.Apply(tfs)
+
 		output := fl.String()
 
 		if output != test.expected {
@@ -591,10 +595,7 @@ func TestPathFlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := &PathFlag{Name: test.name, Aliases: test.aliases, Value: test.value, EnvVars: []string{"APP_PATH"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_PATH]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_PATH%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_PATH"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%s does not end with"+expectedSuffix, output)
 		}
@@ -688,10 +689,7 @@ func TestStringSliceFlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := &StringSliceFlag{Name: test.name, Aliases: test.aliases, Value: test.value, EnvVars: []string{"APP_QWWX"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_QWWX]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_QWWX%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_QWWX"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%q does not end with"+expectedSuffix, output)
 		}
@@ -767,6 +765,11 @@ var intFlagTests = []struct {
 func TestIntFlagHelpOutput(t *testing.T) {
 	for _, test := range intFlagTests {
 		fl := &IntFlag{Name: test.name, Value: 9}
+
+		// create a temporary flag set to apply
+		tfs := flag.NewFlagSet("test", 0)
+		fl.Apply(tfs)
+
 		output := fl.String()
 
 		if output != test.expected {
@@ -784,10 +787,7 @@ func TestIntFlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := &IntFlag{Name: test.name, EnvVars: []string{"APP_BAR"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_BAR]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_BAR%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_BAR"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%s does not end with"+expectedSuffix, output)
 		}
@@ -824,6 +824,11 @@ var int64FlagTests = []struct {
 func TestInt64FlagHelpOutput(t *testing.T) {
 	for _, test := range int64FlagTests {
 		fl := Int64Flag{Name: test.name, Value: 8589934592}
+
+		// create a temporary flag set to apply
+		tfs := flag.NewFlagSet("test", 0)
+		fl.Apply(tfs)
+
 		output := fl.String()
 
 		if output != test.expected {
@@ -841,10 +846,7 @@ func TestInt64FlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := IntFlag{Name: test.name, EnvVars: []string{"APP_BAR"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_BAR]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_BAR%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_BAR"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%s does not end with"+expectedSuffix, output)
 		}
@@ -870,6 +872,11 @@ var uintFlagTests = []struct {
 func TestUintFlagHelpOutput(t *testing.T) {
 	for _, test := range uintFlagTests {
 		fl := UintFlag{Name: test.name, Value: 41}
+
+		// create a temporary flag set to apply
+		tfs := flag.NewFlagSet("test", 0)
+		fl.Apply(tfs)
+
 		output := fl.String()
 
 		if output != test.expected {
@@ -887,10 +894,7 @@ func TestUintFlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := UintFlag{Name: test.name, EnvVars: []string{"APP_BAR"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_BAR]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_BAR%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_BAR"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%s does not end with"+expectedSuffix, output)
 		}
@@ -916,6 +920,11 @@ var uint64FlagTests = []struct {
 func TestUint64FlagHelpOutput(t *testing.T) {
 	for _, test := range uint64FlagTests {
 		fl := Uint64Flag{Name: test.name, Value: 8589934582}
+
+		// create a temporary flag set to apply
+		tfs := flag.NewFlagSet("test", 0)
+		fl.Apply(tfs)
+
 		output := fl.String()
 
 		if output != test.expected {
@@ -933,10 +942,7 @@ func TestUint64FlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := UintFlag{Name: test.name, EnvVars: []string{"APP_BAR"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_BAR]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_BAR%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_BAR"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%s does not end with"+expectedSuffix, output)
 		}
@@ -962,6 +968,11 @@ var durationFlagTests = []struct {
 func TestDurationFlagHelpOutput(t *testing.T) {
 	for _, test := range durationFlagTests {
 		fl := &DurationFlag{Name: test.name, Value: 1 * time.Second}
+
+		// create a temporary flag set to apply
+		tfs := flag.NewFlagSet("test", 0)
+		fl.Apply(tfs)
+
 		output := fl.String()
 
 		if output != test.expected {
@@ -979,10 +990,7 @@ func TestDurationFlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := &DurationFlag{Name: test.name, EnvVars: []string{"APP_BAR"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_BAR]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_BAR%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_BAR"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%s does not end with"+expectedSuffix, output)
 		}
@@ -1039,10 +1047,7 @@ func TestIntSliceFlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := &IntSliceFlag{Name: test.name, Aliases: test.aliases, Value: test.value, EnvVars: []string{"APP_SMURF"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_SMURF]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_SMURF%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_SMURF"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%q does not end with"+expectedSuffix, output)
 		}
@@ -1178,10 +1183,7 @@ func TestInt64SliceFlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := Int64SliceFlag{Name: test.name, Value: test.value, EnvVars: []string{"APP_SMURF"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_SMURF]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_SMURF%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_SMURF"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%q does not end with"+expectedSuffix, output)
 		}
@@ -1332,10 +1334,7 @@ func TestUintSliceFlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := UintSliceFlag{Name: test.name, Value: test.value, EnvVars: []string{"APP_SMURF"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_SMURF]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_SMURF%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_SMURF"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%q does not end with"+expectedSuffix, output)
 		}
@@ -1478,10 +1477,7 @@ func TestUint64SliceFlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := Uint64SliceFlag{Name: test.name, Value: test.value, EnvVars: []string{"APP_SMURF"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_SMURF]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_SMURF%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_SMURF"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%q does not end with"+expectedSuffix, output)
 		}
@@ -1620,10 +1616,7 @@ func TestFloat64FlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := &Float64Flag{Name: test.name, EnvVars: []string{"APP_BAZ"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_BAZ]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_BAZ%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_BAZ"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%s does not end with"+expectedSuffix, output)
 		}
@@ -1680,10 +1673,7 @@ func TestFloat64SliceFlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := Float64SliceFlag{Name: test.name, Value: test.value, EnvVars: []string{"APP_SMURF"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_SMURF]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_SMURF%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_SMURF"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%q does not end with"+expectedSuffix, output)
 		}
@@ -1783,6 +1773,9 @@ var genericFlagTests = []struct {
 func TestGenericFlagHelpOutput(t *testing.T) {
 	for _, test := range genericFlagTests {
 		fl := &GenericFlag{Name: test.name, Value: test.value, Usage: "test flag"}
+		// create a temporary flag set to apply
+		tfs := flag.NewFlagSet("test", 0)
+		fl.Apply(tfs)
 		output := fl.String()
 
 		if output != test.expected {
@@ -1800,10 +1793,7 @@ func TestGenericFlagWithEnvVarHelpOutput(t *testing.T) {
 		fl := &GenericFlag{Name: test.name, EnvVars: []string{"APP_ZAP"}}
 		output := fl.String()
 
-		expectedSuffix := " [$APP_ZAP]"
-		if runtime.GOOS == "windows" {
-			expectedSuffix = " [%APP_ZAP%]"
-		}
+		expectedSuffix := withEnvHint([]string{"APP_ZAP"}, "")
 		if !strings.HasSuffix(output, expectedSuffix) {
 			t.Errorf("%s does not end with"+expectedSuffix, output)
 		}
@@ -3100,6 +3090,186 @@ func TestFlagDefaultValue(t *testing.T) {
 	}
 }
 
+type flagDefaultTestCaseWithEnv struct {
+	name    string
+	flag    Flag
+	toParse []string
+	expect  string
+	environ map[string]string
+}
+
+func TestFlagDefaultValueWithEnv(t *testing.T) {
+	defer resetEnv(os.Environ())
+	os.Clearenv()
+
+	ts, err := time.Parse(time.RFC3339, "2005-01-02T15:04:05Z")
+	if err != nil {
+		t.Fatal(err)
+	}
+	cases := []*flagDefaultTestCaseWithEnv{
+		{
+			name:    "stringSlice",
+			flag:    &StringSliceFlag{Name: "flag", Value: NewStringSlice("default1", "default2"), EnvVars: []string{"ssflag"}},
+			toParse: []string{"--flag", "parsed"},
+			expect:  `--flag value [ --flag value ]	(default: "default1", "default2")` + withEnvHint([]string{"ssflag"}, ""),
+			environ: map[string]string{
+				"ssflag": "some-other-env_value",
+			},
+		},
+		{
+			name:    "float64Slice",
+			flag:    &Float64SliceFlag{Name: "flag", Value: NewFloat64Slice(1.1, 2.2), EnvVars: []string{"fsflag"}},
+			toParse: []string{"--flag", "13.3"},
+			expect:  `--flag value [ --flag value ]	(default: 1.1, 2.2)` + withEnvHint([]string{"fsflag"}, ""),
+			environ: map[string]string{
+				"fsflag": "20304.222",
+			},
+		},
+		{
+			name:    "int64Slice",
+			flag:    &Int64SliceFlag{Name: "flag", Value: NewInt64Slice(1, 2), EnvVars: []string{"isflag"}},
+			toParse: []string{"--flag", "13"},
+			expect:  `--flag value [ --flag value ]	(default: 1, 2)` + withEnvHint([]string{"isflag"}, ""),
+			environ: map[string]string{
+				"isflag": "101",
+			},
+		},
+		{
+			name:    "intSlice",
+			flag:    &IntSliceFlag{Name: "flag", Value: NewIntSlice(1, 2), EnvVars: []string{"isflag"}},
+			toParse: []string{"--flag", "13"},
+			expect:  `--flag value [ --flag value ]	(default: 1, 2)` + withEnvHint([]string{"isflag"}, ""),
+			environ: map[string]string{
+				"isflag": "101",
+			},
+		},
+		{
+			name:    "uint64Slice",
+			flag:    &Uint64SliceFlag{Name: "flag", Value: NewUint64Slice(1, 2), EnvVars: []string{"uisflag"}},
+			toParse: []string{"--flag", "13"},
+			expect:  `--flag value [ --flag value ]	(default: 1, 2)` + withEnvHint([]string{"uisflag"}, ""),
+			environ: map[string]string{
+				"uisflag": "3",
+			},
+		},
+		{
+			name:    "uintSlice",
+			flag:    &UintSliceFlag{Name: "flag", Value: NewUintSlice(1, 2), EnvVars: []string{"uisflag"}},
+			toParse: []string{"--flag", "13"},
+			expect:  `--flag value [ --flag value ]	(default: 1, 2)` + withEnvHint([]string{"uisflag"}, ""),
+			environ: map[string]string{
+				"uisflag": "3",
+			},
+		},
+		{
+			name:    "string",
+			flag:    &StringFlag{Name: "flag", Value: "default", EnvVars: []string{"uflag"}},
+			toParse: []string{"--flag", "parsed"},
+			expect:  `--flag value	(default: "default")` + withEnvHint([]string{"uflag"}, ""),
+			environ: map[string]string{
+				"uflag": "some-other-string",
+			},
+		},
+		{
+			name:    "bool",
+			flag:    &BoolFlag{Name: "flag", Value: true, EnvVars: []string{"uflag"}},
+			toParse: []string{"--flag", "false"},
+			expect:  `--flag	(default: true)` + withEnvHint([]string{"uflag"}, ""),
+			environ: map[string]string{
+				"uflag": "false",
+			},
+		},
+		{
+			name:    "uint64",
+			flag:    &Uint64Flag{Name: "flag", Value: 1, EnvVars: []string{"uflag"}},
+			toParse: []string{"--flag", "13"},
+			expect:  `--flag value	(default: 1)` + withEnvHint([]string{"uflag"}, ""),
+			environ: map[string]string{
+				"uflag": "10",
+			},
+		},
+		{
+			name:    "uint",
+			flag:    &UintFlag{Name: "flag", Value: 1, EnvVars: []string{"uflag"}},
+			toParse: []string{"--flag", "13"},
+			expect:  `--flag value	(default: 1)` + withEnvHint([]string{"uflag"}, ""),
+			environ: map[string]string{
+				"uflag": "10",
+			},
+		},
+		{
+			name:    "int64",
+			flag:    &Int64Flag{Name: "flag", Value: 1, EnvVars: []string{"uflag"}},
+			toParse: []string{"--flag", "13"},
+			expect:  `--flag value	(default: 1)` + withEnvHint([]string{"uflag"}, ""),
+			environ: map[string]string{
+				"uflag": "10",
+			},
+		},
+		{
+			name:    "int",
+			flag:    &IntFlag{Name: "flag", Value: 1, EnvVars: []string{"uflag"}},
+			toParse: []string{"--flag", "13"},
+			expect:  `--flag value	(default: 1)` + withEnvHint([]string{"uflag"}, ""),
+			environ: map[string]string{
+				"uflag": "10",
+			},
+		},
+		{
+			name:    "duration",
+			flag:    &DurationFlag{Name: "flag", Value: time.Second, EnvVars: []string{"uflag"}},
+			toParse: []string{"--flag", "2m"},
+			expect:  `--flag value	(default: 1s)` + withEnvHint([]string{"uflag"}, ""),
+			environ: map[string]string{
+				"uflag": "2h4m10s",
+			},
+		},
+		{
+			name:    "path",
+			flag:    &PathFlag{Name: "flag", Value: "/tmp/foo", EnvVars: []string{"uflag"}},
+			toParse: []string{"--flag", "/bar/ddfr"},
+			expect:  `--flag value	(default: "/tmp/foo")` + withEnvHint([]string{"uflag"}, ""),
+			environ: map[string]string{
+				"uflag": "/bar/t/err",
+			},
+		},
+		{
+			name:    "timestamp",
+			flag:    &TimestampFlag{Name: "flag", Value: NewTimestamp(ts), Layout: time.RFC3339, EnvVars: []string{"tflag"}},
+			toParse: []string{"--flag", "2006-11-02T15:04:05Z"},
+			expect:  `--flag value	(default: 2005-01-02 15:04:05 +0000 UTC)` + withEnvHint([]string{"tflag"}, ""),
+			environ: map[string]string{
+				"tflag": "2010-01-02T15:04:05Z",
+			},
+		},
+		{
+			name:    "generic",
+			flag:    &GenericFlag{Name: "flag", Value: &Parser{"11", "12"}, EnvVars: []string{"gflag"}},
+			toParse: []string{"--flag", "15,16"},
+			expect:  `--flag value	(default: 11,12)` + withEnvHint([]string{"gflag"}, ""),
+			environ: map[string]string{
+				"gflag": "13,14",
+			},
+		},
+	}
+	for i, v := range cases {
+		for key, val := range v.environ {
+			os.Setenv(key, val)
+		}
+		set := flag.NewFlagSet("test", 0)
+		set.SetOutput(ioutil.Discard)
+		if err := v.flag.Apply(set); err != nil {
+			t.Fatal(err)
+		}
+		if err := set.Parse(v.toParse); err != nil {
+			t.Error(err)
+		}
+		if got := v.flag.String(); got != v.expect {
+			t.Errorf("TestFlagDefaultValue %d %s\nexpect:%s\ngot:%s", i, v.name, v.expect, got)
+		}
+	}
+}
+
 type flagValueTestCase struct {
 	name    string
 	flag    Flag

flag_timestamp.go

@@ -72,6 +72,25 @@ func (t *Timestamp) Get() interface{} {
 	return *t
 }
 
+// clone timestamp
+func (t *Timestamp) clone() *Timestamp {
+	tc := &Timestamp{
+		timestamp:  nil,
+		hasBeenSet: t.hasBeenSet,
+		layout:     t.layout,
+		location:   nil,
+	}
+	if t.timestamp != nil {
+		tts := *t.timestamp
+		tc.timestamp = &tts
+	}
+	if t.location != nil {
+		loc := *t.location
+		tc.location = &loc
+	}
+	return tc
+}
+
 // GetValue returns the flags value as string representation and an empty
 // string if the flag takes no value at all.
 func (f *TimestampFlag) GetValue() string {
@@ -86,7 +105,11 @@ func (f *TimestampFlag) GetDefaultText() string {
 	if f.DefaultText != "" {
 		return f.DefaultText
 	}
-	return f.GetValue()
+	if f.defaultValue != nil && f.defaultValue.timestamp != nil {
+		return f.defaultValue.timestamp.String()
+	}
+
+	return ""
 }
 
 // Apply populates the flag given the flag set and environment
@@ -100,6 +123,8 @@ func (f *TimestampFlag) Apply(set *flag.FlagSet) error {
 	f.Value.SetLayout(f.Layout)
 	f.Value.SetLocation(f.Timezone)
 
+	f.defaultValue = f.Value.clone()
+
 	if f.Destination != nil {
 		f.Destination.SetLayout(f.Layout)
 		f.Destination.SetLocation(f.Timezone)

flag_uint.go

@@ -8,6 +8,9 @@ import (
 
 // Apply populates the flag given the flag set and environment
 func (f *UintFlag) Apply(set *flag.FlagSet) error {
+	// set default value so that environment wont be able to overwrite it
+	f.defaultValue = f.Value
+
 	if val, source, found := flagFromEnvOrFile(f.EnvVars, f.FilePath); found {
 		if val != "" {
 			valInt, err := strconv.ParseUint(val, f.Base, 64)
@@ -42,7 +45,7 @@ func (f *UintFlag) GetDefaultText() string {
 	if f.DefaultText != "" {
 		return f.DefaultText
 	}
-	return f.GetValue()
+	return fmt.Sprintf("%d", f.defaultValue)
 }
 
 // Get returns the flag’s value in the given Context.

flag_uint64.go

@@ -8,6 +8,9 @@ import (
 
 // Apply populates the flag given the flag set and environment
 func (f *Uint64Flag) Apply(set *flag.FlagSet) error {
+	// set default value so that environment wont be able to overwrite it
+	f.defaultValue = f.Value
+
 	if val, source, found := flagFromEnvOrFile(f.EnvVars, f.FilePath); found {
 		if val != "" {
 			valInt, err := strconv.ParseUint(val, f.Base, 64)
@@ -42,7 +45,7 @@ func (f *Uint64Flag) GetDefaultText() string {
 	if f.DefaultText != "" {
 		return f.DefaultText
 	}
-	return f.GetValue()
+	return fmt.Sprintf("%d", f.defaultValue)
 }
 
 // Get returns the flag’s value in the given Context.

godoc-current.txt

@@ -445,6 +445,7 @@ type BoolFlag struct {
 	Count *int
 
 	Action func(*Context, bool) error
+	// Has unexported fields.
 }
     BoolFlag is a flag with type bool
 
@@ -774,6 +775,7 @@ type DurationFlag struct {
 	EnvVars []string
 
 	Action func(*Context, time.Duration) error
+	// Has unexported fields.
 }
     DurationFlag is a flag with type time.Duration
 
@@ -957,6 +959,7 @@ type Float64Flag struct {
 	EnvVars []string
 
 	Action func(*Context, float64) error
+	// Has unexported fields.
 }
     Float64Flag is a flag with type float64
 
@@ -1045,6 +1048,7 @@ type Float64SliceFlag struct {
 	EnvVars []string
 
 	Action func(*Context, []float64) error
+	// Has unexported fields.
 }
     Float64SliceFlag is a flag with type *Float64Slice
 
@@ -1127,6 +1131,7 @@ type GenericFlag struct {
 	TakesFile bool
 
 	Action func(*Context, interface{}) error
+	// Has unexported fields.
 }
     GenericFlag is a flag with type Generic
 
@@ -1195,6 +1200,7 @@ type Int64Flag struct {
 	Base int
 
 	Action func(*Context, int64) error
+	// Has unexported fields.
 }
     Int64Flag is a flag with type int64
 
@@ -1283,6 +1289,7 @@ type Int64SliceFlag struct {
 	EnvVars []string
 
 	Action func(*Context, []int64) error
+	// Has unexported fields.
 }
     Int64SliceFlag is a flag with type *Int64Slice
 
@@ -1359,6 +1366,7 @@ type IntFlag struct {
 	Base int
 
 	Action func(*Context, int) error
+	// Has unexported fields.
 }
     IntFlag is a flag with type int
 
@@ -1451,6 +1459,7 @@ type IntSliceFlag struct {
 	EnvVars []string
 
 	Action func(*Context, []int) error
+	// Has unexported fields.
 }
     IntSliceFlag is a flag with type *IntSlice
 
@@ -1561,6 +1570,7 @@ type PathFlag struct {
 	TakesFile bool
 
 	Action func(*Context, Path) error
+	// Has unexported fields.
 }
     PathFlag is a flag with type Path
 
@@ -1704,6 +1714,7 @@ type StringFlag struct {
 	TakesFile bool
 
 	Action func(*Context, string) error
+	// Has unexported fields.
 }
     StringFlag is a flag with type string
 
@@ -1794,6 +1805,7 @@ type StringSliceFlag struct {
 	TakesFile bool
 
 	Action func(*Context, []string) error
+	// Has unexported fields.
 }
     StringSliceFlag is a flag with type *StringSlice
 
@@ -1905,6 +1917,7 @@ type TimestampFlag struct {
 	Timezone *time.Location
 
 	Action func(*Context, *time.Time) error
+	// Has unexported fields.
 }
     TimestampFlag is a flag with type *Timestamp
 
@@ -1972,6 +1985,7 @@ type Uint64Flag struct {
 	Base int
 
 	Action func(*Context, uint64) error
+	// Has unexported fields.
 }
     Uint64Flag is a flag with type uint64
 
@@ -2060,6 +2074,7 @@ type Uint64SliceFlag struct {
 	EnvVars []string
 
 	Action func(*Context, []uint64) error
+	// Has unexported fields.
 }
     Uint64SliceFlag is a flag with type *Uint64Slice
 
@@ -2130,6 +2145,7 @@ type UintFlag struct {
 	Base int
 
 	Action func(*Context, uint) error
+	// Has unexported fields.
 }
     UintFlag is a flag with type uint
 
@@ -2222,6 +2238,7 @@ type UintSliceFlag struct {
 	EnvVars []string
 
 	Action func(*Context, []uint) error
+	// Has unexported fields.
 }
     UintSliceFlag is a flag with type *UintSlice
 

testdata/godoc-v2.x.txt

@@ -445,6 +445,7 @@ type BoolFlag struct {
 	Count *int
 
 	Action func(*Context, bool) error
+	// Has unexported fields.
 }
     BoolFlag is a flag with type bool
 
@@ -774,6 +775,7 @@ type DurationFlag struct {
 	EnvVars []string
 
 	Action func(*Context, time.Duration) error
+	// Has unexported fields.
 }
     DurationFlag is a flag with type time.Duration
 
@@ -957,6 +959,7 @@ type Float64Flag struct {
 	EnvVars []string
 
 	Action func(*Context, float64) error
+	// Has unexported fields.
 }
     Float64Flag is a flag with type float64
 
@@ -1045,6 +1048,7 @@ type Float64SliceFlag struct {
 	EnvVars []string
 
 	Action func(*Context, []float64) error
+	// Has unexported fields.
 }
     Float64SliceFlag is a flag with type *Float64Slice
 
@@ -1127,6 +1131,7 @@ type GenericFlag struct {
 	TakesFile bool
 
 	Action func(*Context, interface{}) error
+	// Has unexported fields.
 }
     GenericFlag is a flag with type Generic
 
@@ -1195,6 +1200,7 @@ type Int64Flag struct {
 	Base int
 
 	Action func(*Context, int64) error
+	// Has unexported fields.
 }
     Int64Flag is a flag with type int64
 
@@ -1283,6 +1289,7 @@ type Int64SliceFlag struct {
 	EnvVars []string
 
 	Action func(*Context, []int64) error
+	// Has unexported fields.
 }
     Int64SliceFlag is a flag with type *Int64Slice
 
@@ -1359,6 +1366,7 @@ type IntFlag struct {
 	Base int
 
 	Action func(*Context, int) error
+	// Has unexported fields.
 }
     IntFlag is a flag with type int
 
@@ -1451,6 +1459,7 @@ type IntSliceFlag struct {
 	EnvVars []string
 
 	Action func(*Context, []int) error
+	// Has unexported fields.
 }
     IntSliceFlag is a flag with type *IntSlice
 
@@ -1561,6 +1570,7 @@ type PathFlag struct {
 	TakesFile bool
 
 	Action func(*Context, Path) error
+	// Has unexported fields.
 }
     PathFlag is a flag with type Path
 
@@ -1704,6 +1714,7 @@ type StringFlag struct {
 	TakesFile bool
 
 	Action func(*Context, string) error
+	// Has unexported fields.
 }
     StringFlag is a flag with type string
 
@@ -1794,6 +1805,7 @@ type StringSliceFlag struct {
 	TakesFile bool
 
 	Action func(*Context, []string) error
+	// Has unexported fields.
 }
     StringSliceFlag is a flag with type *StringSlice
 
@@ -1905,6 +1917,7 @@ type TimestampFlag struct {
 	Timezone *time.Location
 
 	Action func(*Context, *time.Time) error
+	// Has unexported fields.
 }
     TimestampFlag is a flag with type *Timestamp
 
@@ -1972,6 +1985,7 @@ type Uint64Flag struct {
 	Base int
 
 	Action func(*Context, uint64) error
+	// Has unexported fields.
 }
     Uint64Flag is a flag with type uint64
 
@@ -2060,6 +2074,7 @@ type Uint64SliceFlag struct {
 	EnvVars []string
 
 	Action func(*Context, []uint64) error
+	// Has unexported fields.
 }
     Uint64SliceFlag is a flag with type *Uint64Slice
 
@@ -2130,6 +2145,7 @@ type UintFlag struct {
 	Base int
 
 	Action func(*Context, uint) error
+	// Has unexported fields.
 }
     UintFlag is a flag with type uint
 
@@ -2222,6 +2238,7 @@ type UintSliceFlag struct {
 	EnvVars []string
 
 	Action func(*Context, []uint) error
+	// Has unexported fields.
 }
     UintSliceFlag is a flag with type *UintSlice
 

zz_generated.flags.go

@@ -23,6 +23,8 @@ type Float64SliceFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue *Float64Slice
+
 	Action func(*Context, []float64) error
 }
 
@@ -85,6 +87,8 @@ type GenericFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue Generic
+
 	TakesFile bool
 
 	Action func(*Context, interface{}) error
@@ -154,6 +158,8 @@ type Int64SliceFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue *Int64Slice
+
 	Action func(*Context, []int64) error
 }
 
@@ -216,6 +222,8 @@ type IntSliceFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue *IntSlice
+
 	Action func(*Context, []int) error
 }
 
@@ -278,6 +286,8 @@ type PathFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue Path
+
 	TakesFile bool
 
 	Action func(*Context, Path) error
@@ -347,6 +357,8 @@ type StringSliceFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue *StringSlice
+
 	TakesFile bool
 
 	Action func(*Context, []string) error
@@ -411,6 +423,8 @@ type TimestampFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue *Timestamp
+
 	Layout string
 
 	Timezone *time.Location
@@ -482,6 +496,8 @@ type Uint64SliceFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue *Uint64Slice
+
 	Action func(*Context, []uint64) error
 }
 
@@ -544,6 +560,8 @@ type UintSliceFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue *UintSlice
+
 	Action func(*Context, []uint) error
 }
 
@@ -606,6 +624,8 @@ type BoolFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue bool
+
 	Count *int
 
 	Action func(*Context, bool) error
@@ -675,6 +695,8 @@ type Float64Flag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue float64
+
 	Action func(*Context, float64) error
 }
 
@@ -742,6 +764,8 @@ type IntFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue int
+
 	Base int
 
 	Action func(*Context, int) error
@@ -811,6 +835,8 @@ type Int64Flag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue int64
+
 	Base int
 
 	Action func(*Context, int64) error
@@ -880,6 +906,8 @@ type StringFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue string
+
 	TakesFile bool
 
 	Action func(*Context, string) error
@@ -949,6 +977,8 @@ type DurationFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue time.Duration
+
 	Action func(*Context, time.Duration) error
 }
 
@@ -1016,6 +1046,8 @@ type UintFlag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue uint
+
 	Base int
 
 	Action func(*Context, uint) error
@@ -1085,6 +1117,8 @@ type Uint64Flag struct {
 	Aliases []string
 	EnvVars []string
 
+	defaultValue uint64
+
 	Base int
 
 	Action func(*Context, uint64) error