test that short-only options are printed first in the help message

usage.go

@@ -117,9 +117,6 @@ func (p *Parser) writeUsageForCommand(w io.Writer, cmd *command) {
 }
 
 func printTwoCols(w io.Writer, left, help string, defaultVal string, envVal string) {
-	if left == "" {
-		return
-	}
 	lhs := "  " + left
 	fmt.Fprint(w, lhs)
 	if help != "" {
@@ -162,12 +159,15 @@ func (p *Parser) WriteHelp(w io.Writer) {
 
 // writeHelp writes the usage string for the given subcommand
 func (p *Parser) writeHelpForCommand(w io.Writer, cmd *command) {
-	var positionals, options []*spec
+	var positionals, longOptions, shortOptions []*spec
 	for _, spec := range cmd.specs {
-		if spec.positional {
+		switch {
+		case spec.positional:
 			positionals = append(positionals, spec)
-		} else {
+		case spec.long != "":
-			options = append(options, spec)
+			longOptions = append(longOptions, spec)
+		case spec.short != "":
+			shortOptions = append(shortOptions, spec)
 		}
 	}
 
@@ -184,10 +184,13 @@ func (p *Parser) writeHelpForCommand(w io.Writer, cmd *command) {
 		}
 	}
 
-	// write the list of options
+	// write the list of options with the short-only ones first to match the usage string
-	if len(options) > 0 || cmd.parent == nil {
+	if len(shortOptions)+len(longOptions) > 0 || cmd.parent == nil {
 		fmt.Fprint(w, "\nOptions:\n")
-		for _, spec := range options {
+		for _, spec := range shortOptions {
+			p.printOption(w, spec)
+		}
+		for _, spec := range longOptions {
 			p.printOption(w, spec)
 		}
 	}
@@ -233,15 +236,16 @@ func (p *Parser) writeHelpForCommand(w io.Writer, cmd *command) {
 }
 
 func (p *Parser) printOption(w io.Writer, spec *spec) {
-	text := make([]string, 0, 2)
+	ways := make([]string, 0, 2)
 	if spec.long != "" {
-		text = append(text, synopsis(spec, "--"+spec.long))
+		ways = append(ways, synopsis(spec, "--"+spec.long))
 	}
 	if spec.short != "" {
-		text = append(text, synopsis(spec, "-"+spec.short))
+		ways = append(ways, synopsis(spec, "-"+spec.short))
+	}
+	if len(ways) > 0 {
+		printTwoCols(w, strings.Join(ways, ", "), spec.help, spec.defaultVal, spec.env)
 	}
-	left := strings.Join(text, ", ")
-	printTwoCols(w, left, spec.help, spec.defaultVal, spec.env)
 }
 
 func synopsis(spec *spec, form string) string {

usage_test.go

@@ -310,7 +310,7 @@ Global options:
 	assert.Equal(t, expectedHelp, help.String())
 }
 
-func TestUsageWithOptionalLongNames(t *testing.T) {
+func TestUsageWithoutLongNames(t *testing.T) {
 	expectedHelp := `Usage: example [-a PLACEHOLDER] -b SHORTONLY2
 
 Options:
@@ -329,6 +329,25 @@ Options:
 	assert.Equal(t, expectedHelp, help.String())
 }
 
+func TestUsageWithShortFirst(t *testing.T) {
+	expectedHelp := `Usage: example [-c CAT] [--dog DOG]
+
+Options:
+  -c CAT
+  --dog DOG
+  --help, -h             display this help and exit
+`
+	var args struct {
+		Dog string
+		Cat string `arg:"-c,--"`
+	}
+	p, err := NewParser(Config{Program: "example"}, &args)
+	assert.NoError(t, err)
+	var help bytes.Buffer
+	p.WriteHelp(&help)
+	assert.Equal(t, expectedHelp, help.String())
+}
+
 func TestUsageWithEnvOptions(t *testing.T) {
 	expectedHelp := `Usage: example [-s SHORT]