Also print cmd usage string on "unknown command"

mislav · mislav · commit e87775845d3e · 2019-10-31T22:44:43.000+01:00
diff --git a/command/root.go b/command/root.go
@@ -1,7 +1,6 @@
 package command
 
 import (
-	"errors"
 	"fmt"
 	"os"
 
@@ -19,13 +18,14 @@ func init() {
 	// RootCmd.PersistentFlags().BoolP("verbose", "V", false, "enable verbose output")
 
 	RootCmd.SetFlagErrorFunc(func(cmd *cobra.Command, err error) error {
-		cmd.Println(err)
-		cmd.Println(cmd.UsageString())
-		return SilentErr
+		return FlagError{err}
 	})
 }
 
-var SilentErr = errors.New("SilentErr")
+// FlagError is the kind of error raised in flag processing
+type FlagError struct {
+	error
+}
 
 // RootCmd is the entry point of command-line execution
 var RootCmd = &cobra.Command{
diff --git a/main.go b/main.go
@@ -3,14 +3,17 @@ package main
 import (
 	"fmt"
 	"os"
+	"strings"
 
 	"github.com/github/gh-cli/command"
 )
 
 func main() {
-	if err := command.RootCmd.Execute(); err != nil {
-		if err != command.SilentErr {
-			fmt.Fprintln(os.Stderr, err)
+	if cmd, err := command.RootCmd.ExecuteC(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		_, isFlagError := err.(command.FlagError)
+		if isFlagError || strings.HasPrefix(err.Error(), "unknown command ") {
+			fmt.Fprintln(os.Stderr, cmd.UsageString())
 		}
 		os.Exit(1)
 	}

Original file line number	Diff line number	Diff line change
`@@ -3,14 +3,17 @@ package main`
`3`	`3`	`import (`
`4`	`4`	`"fmt"`
`5`	`5`	`"os"`
	`6`	`+ "strings"`
`6`	`7`
`7`	`8`	`"github.com/github/gh-cli/command"`
`8`	`9`	`)`
`9`	`10`
`10`	`11`	`func main() {`
`11`		`- if err := command.RootCmd.Execute(); err != nil {`
`12`		`- if err != command.SilentErr {`
`13`		`- fmt.Fprintln(os.Stderr, err)`
	`12`	`+ if cmd, err := command.RootCmd.ExecuteC(); err != nil {`
	`13`	`+ fmt.Fprintln(os.Stderr, err)`
	`14`	`+ _, isFlagError := err.(command.FlagError)`
	`15`	`+ if isFlagError \|\| strings.HasPrefix(err.Error(), "unknown command ") {`
	`16`	`+ fmt.Fprintln(os.Stderr, cmd.UsageString())`
`14`	`17`	`}`
`15`	`18`	`os.Exit(1)`
`16`	`19`	`}`