feat(help): add -h short flag for --help

CHANGELOG.md

@@ -14,6 +14,8 @@
 
 ### Enhancements:
 
+- feat(help): add -h short flag for --help. ([#1918](https://github.com/fastly/cli/pull/1918))
+
 ### Dependencies:
 - build(deps): `github.com/andybalholm/brotli` from 1.2.3 to 1.2.4 ([#1913](https://github.com/fastly/cli/pull/1913))
 - build(deps): `github.com/mattn/go-runewidth` from 0.0.29 to 0.0.30 ([#1913](https://github.com/fastly/cli/pull/1913))

pkg/app/run.go

@@ -359,6 +359,14 @@ func configureKingpin(data *global.Data) *kingpin.Application {
 	// Prevent kingpin from calling os.Exit, this gives us greater control over
 	// error states and output control flow.
 	app.Terminate(nil)
+	// The `help` flag is not one we registered ourselves: kingpin defines it
+	// internally when the application is created. We look it up by name to
+	// attach the `-h` shorthand, and only guard with a nil check because if a
+	// future kingpin version renamed or removed its built-in help flag we
+	// would panic here at startup instead of failing gracefully.
+	if helpFlag := app.GetFlag("help"); helpFlag != nil {
+		helpFlag.Short('h')
+	}
 
 	// IMPORTANT: Kingpin doesn't support global flags.
 	// Any flags defined below must also be added to two other places:

pkg/app/run_test.go

@@ -5,6 +5,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	stderrors "errors"
 	"io"
 	"os"
 	"strings"
@@ -278,6 +279,36 @@ func TestHelpJSON(t *testing.T) {
 	}
 }
 
+// TestShortHelpFlag verifies that `-h` displays the usage template just like `--help`.
+func TestShortHelpFlag(t *testing.T) {
+	for _, flag := range []string{"--help", "-h"} {
+		t.Run(flag, func(t *testing.T) {
+			var stdout bytes.Buffer
+			args := testutil.SplitArgs(flag)
+			app.Init = func(_ []string, _ io.Reader) (*global.Data, error) {
+				return testutil.MockGlobalData(args, &stdout), nil
+			}
+			err := app.Run(args, nil)
+			var output string
+			if err != nil {
+				var re errors.RemediationError
+				var se errors.SkipExitError
+				if ok := stderrors.As(err, &re); ok {
+					output = re.Prefix
+				} else if ok := stderrors.As(err, &se); ok {
+					if re, ok := se.Err.(errors.RemediationError); ok {
+						output = re.Prefix
+					}
+				}
+			}
+			output += stdout.String()
+			if !strings.Contains(output, "USAGE") {
+				t.Errorf("expected usage output containing \"USAGE\", got: %s", output)
+			}
+		})
+	}
+}
+
 // stripTrailingSpace removes any trailing spaces from the multiline str.
 func stripTrailingSpace(str string) string {
 	buf := bytes.NewBuffer(nil)

pkg/argparser/cmd.go

@@ -283,9 +283,9 @@ func IsHelpOnly(args []string) bool {
 	return len(args) > 0 && args[0] == "help"
 }
 
-// IsHelpFlagOnly indicates if the user called `fastly --help [...]`.
+// IsHelpFlagOnly indicates if the user called `fastly --help [...]` or `fastly -h [...]`.
 func IsHelpFlagOnly(args []string) bool {
-	return len(args) > 0 && args[0] == "--help"
+	return len(args) > 0 && (args[0] == "--help" || args[0] == "-h")
 }
 
 // IsVerboseAndQuiet indicates if the user called `fastly --verbose --quiet`.
@@ -338,6 +338,7 @@ func IsGlobalFlagsOnly(args []string) bool {
 		"--debug-mode":      0,
 		"--enable-sso":      0,
 		"--help":            0,
+		"-h":                0,
 		"--non-interactive": 0,
 		"-i":                0,
 		"--profile":         1,

pkg/argparser/cmd_test.go

@@ -29,6 +29,16 @@ func TestIsGlobalFlagsOnly(t *testing.T) {
 			args: []string{"-t", "abc"},
 			want: true,
 		},
+		{
+			name: "help flag only",
+			args: []string{"--help"},
+			want: true,
+		},
+		{
+			name: "short help flag only",
+			args: []string{"-h"},
+			want: true,
+		},
 		{
 			name: "subcommand present",
 			args: []string{"--verbose", "version"},
@@ -45,6 +55,48 @@ func TestIsGlobalFlagsOnly(t *testing.T) {
 	}
 }
 
+func TestIsHelpFlagOnly(t *testing.T) {
+	tests := []struct {
+		name string
+		args []string
+		want bool
+	}{
+		{
+			name: "--help",
+			args: []string{"--help"},
+			want: true,
+		},
+		{
+			name: "-h",
+			args: []string{"-h"},
+			want: true,
+		},
+		{
+			name: "-h with subcommand",
+			args: []string{"-h", "service"},
+			want: true,
+		},
+		{
+			name: "subcommand first",
+			args: []string{"service", "-h"},
+			want: false,
+		},
+		{
+			name: "empty",
+			args: []string{},
+			want: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := argparser.IsHelpFlagOnly(tt.args); got != tt.want {
+				t.Errorf("IsHelpFlagOnly(%v) = %v, want %v", tt.args, got, tt.want)
+			}
+		})
+	}
+}
+
 func TestArgsIsHelpJSON(t *testing.T) {
 	tests := []struct {
 		name string