Add SortFlags option (spf13#113)

Fixes spf13/cobra#316

flag.go

@@ -134,10 +134,16 @@ type FlagSet struct {
 	// a custom error handler.
 	Usage func()
 
+	// SortFlags is used to indicate, if user wants to have sorted flags in
+	// help/usage messages.
+	SortFlags bool
+
 	name              string
 	parsed            bool
 	actual            map[NormalizedName]*Flag
+	orderedActual     []*Flag
 	formal            map[NormalizedName]*Flag
+	orderedFormal     []*Flag
 	shorthands        map[byte]*Flag
 	args              []string // arguments after flags
 	argsLenAtDash     int      // len(args) when a '--' was located when parsing, or -1 if no --
@@ -156,7 +162,7 @@ type Flag struct {
 	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
+	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
@@ -194,10 +200,12 @@ func sortFlags(flags map[NormalizedName]*Flag) []*Flag {
 // "--getUrl" which may also be translated to "geturl" and everything will work.
 func (f *FlagSet) SetNormalizeFunc(n func(f *FlagSet, name string) NormalizedName) {
 	f.normalizeNameFunc = n
+	f.orderedFormal = f.orderedFormal[:0]
 	for k, v := range f.formal {
 		delete(f.formal, k)
 		nname := f.normalizeFlagName(string(k))
 		f.formal[nname] = v
+		f.orderedFormal = append(f.orderedFormal, v)
 		v.Name = string(nname)
 	}
 }
@@ -229,10 +237,18 @@ func (f *FlagSet) SetOutput(output io.Writer) {
 	f.output = output
 }
 
-// VisitAll visits the flags in lexicographical order, calling fn for each.
+// VisitAll visits the flags in lexicographical order or
+// in primordial order if f.SortFlags is false, calling fn for each.
 // It visits all flags, even those not set.
 func (f *FlagSet) VisitAll(fn func(*Flag)) {
-	for _, flag := range sortFlags(f.formal) {
+	var flags []*Flag
+	if f.SortFlags {
+		flags = sortFlags(f.formal)
+	} else {
+		flags = f.orderedFormal
+	}
+
+	for _, flag := range flags {
 		fn(flag)
 	}
 }
@@ -253,22 +269,32 @@ func (f *FlagSet) HasAvailableFlags() bool {
 	return false
 }
 
-// VisitAll visits the command-line flags in lexicographical order, calling
-// fn for each.  It visits all flags, even those not set.
+// VisitAll visits the command-line flags in lexicographical order or
+// in primordial order if f.SortFlags is false, calling fn for each.
+// It visits all flags, even those not set.
 func VisitAll(fn func(*Flag)) {
 	CommandLine.VisitAll(fn)
 }
 
-// Visit visits the flags in lexicographical order, calling fn for each.
+// Visit visits the flags in lexicographical order or
+// in primordial order if f.SortFlags is false, calling fn for each.
 // It visits only those flags that have been set.
 func (f *FlagSet) Visit(fn func(*Flag)) {
-	for _, flag := range sortFlags(f.actual) {
+	var flags []*Flag
+	if f.SortFlags {
+		flags = sortFlags(f.actual)
+	} else {
+		flags = f.orderedActual
+	}
+
+	for _, flag := range flags {
 		fn(flag)
 	}
 }
 
-// Visit visits the command-line flags in lexicographical order, calling fn
-// for each.  It visits only those flags that have been set.
+// Visit visits the command-line flags in lexicographical order or
+// in primordial order if f.SortFlags is false, calling fn for each.
+// It visits only those flags that have been set.
 func Visit(fn func(*Flag)) {
 	CommandLine.Visit(fn)
 }
@@ -373,6 +399,7 @@ func (f *FlagSet) Set(name, value string) error {
 		f.actual = make(map[NormalizedName]*Flag)
 	}
 	f.actual[normalName] = flag
+	f.orderedActual = append(f.orderedActual, flag)
 	flag.Changed = true
 	if len(flag.Deprecated) > 0 {
 		fmt.Fprintf(os.Stderr, "Flag --%s has been deprecated, %s\n", flag.Name, flag.Deprecated)
@@ -729,6 +756,7 @@ func (f *FlagSet) AddFlag(flag *Flag) {
 
 	flag.Name = string(normalizedFlagName)
 	f.formal[normalizedFlagName] = flag
+	f.orderedFormal = append(f.orderedFormal, flag)
 
 	if len(flag.Shorthand) == 0 {
 		return
@@ -807,6 +835,7 @@ func (f *FlagSet) setFlag(flag *Flag, value string, origArg string) error {
 		f.actual = make(map[NormalizedName]*Flag)
 	}
 	f.actual[f.normalizeFlagName(flag.Name)] = flag
+	f.orderedActual = append(f.orderedActual, flag)
 	flag.Changed = true
 	if len(flag.Deprecated) > 0 {
 		fmt.Fprintf(os.Stderr, "Flag --%s has been deprecated, %s\n", flag.Name, flag.Deprecated)
@@ -1036,14 +1065,15 @@ func Parsed() bool {
 // CommandLine is the default set of command-line flags, parsed from os.Args.
 var CommandLine = NewFlagSet(os.Args[0], ExitOnError)
 
-// NewFlagSet returns a new, empty flag set with the specified name and
-// error handling property.
+// NewFlagSet returns a new, empty flag set with the specified name,
+// error handling property and SortFlags set to true.
 func NewFlagSet(name string, errorHandling ErrorHandling) *FlagSet {
 	f := &FlagSet{
 		name:          name,
 		errorHandling: errorHandling,
 		argsLenAtDash: -1,
 		interspersed:  true,
+		SortFlags:     true,
 	}
 	return f
 }

flag_test.go

@@ -1004,3 +1004,38 @@ func TestPrintDefaults(t *testing.T) {
 		t.Errorf("got %q want %q\n", got, defaultOutput)
 	}
 }
+
+func TestVisitAllFlagOrder(t *testing.T) {
+	fs := NewFlagSet("TestVisitAllFlagOrder", ContinueOnError)
+	fs.SortFlags = false
+	names := []string{"C", "B", "A", "D"}
+	for _, name := range names {
+		fs.Bool(name, false, "")
+	}
+
+	i := 0
+	fs.VisitAll(func(f *Flag) {
+		if names[i] != f.Name {
+			t.Errorf("Incorrect order. Expected %v, got %v", names[i], f.Name)
+		}
+		i++
+	})
+}
+
+func TestVisitFlagOrder(t *testing.T) {
+	fs := NewFlagSet("TestVisitFlagOrder", ContinueOnError)
+	fs.SortFlags = false
+	names := []string{"C", "B", "A", "D"}
+	for _, name := range names {
+		fs.Bool(name, false, "")
+		fs.Set(name, "true")
+	}
+
+	i := 0
+	fs.Visit(func(f *Flag) {
+		if names[i] != f.Name {
+			t.Errorf("Incorrect order. Expected %v, got %v", names[i], f.Name)
+		}
+		i++
+	})
+}