style: replace stringInSlice

cobra.go

@@ -189,12 +189,3 @@ func ld(s, t string, ignoreCase bool) int {
 	}
 	return d[len(s)][len(t)]
 }
-
-func stringInSlice(a string, list []string) bool {
-	for _, b := range list {
-		if b == a {
-			return true
-		}
-	}
-	return false
-}

command.go

@@ -732,7 +732,7 @@ func (c *Command) execute(a []string) (err error) {
 		argWoFlags = a
 	}
 
-	if err := c.ValidateArgs(argWoFlags); err != nil {
+	if err := c.validateArgs(argWoFlags); err != nil {
 		return err
 	}
 
@@ -873,14 +873,16 @@ func (c *Command) ExecuteC() (cmd *Command, err error) {
 	return cmd, err
 }
 
-func (c *Command) ValidateArgs(args []string) error {
+func (c *Command) validateArgs(args []string) error {
 	if c.Args == nil {
 		return nil
 	}
 	if len(c.ValidArgs) > 0 {
-		for _, v := range args {
-			if !stringInSlice(v, c.ValidArgs) {
-				return fmt.Errorf("invalid argument %q for %q%s", v, c.CommandPath(), c.findSuggestions(args[0]))
+		const p = "$"
+		s := p + strings.Join(c.ValidArgs, p) + p
+		for _, a := range args {
+			if !strings.Contains(s, p+a+p) {
+				return fmt.Errorf("invalid argument %q for %q%s", a, c.CommandPath(), c.findSuggestions(args[0]))
 			}
 		}
 	}

command_test.go

@@ -1414,11 +1414,13 @@ func TestSortedFlags(t *testing.T) {
 		if i == len(names) {
 			return
 		}
-		if stringInSlice(f.Name, names) {
-			if names[i] != f.Name {
-				t.Errorf("Incorrect order. Expected %v, got %v", names[i], f.Name)
+		for _, name := range names {
+			if name == f.Name {
+				if names[i] != f.Name {
+					t.Errorf("Incorrect order. Expected %v, got %v", names[i], f.Name)
+				}
+				i++
 			}
-			i++
 		}
 	})
 }