From d708cada43f31b79462e6d7325fbcfd75b47ae29 Mon Sep 17 00:00:00 2001
From: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
Date: Wed, 10 Oct 2018 18:16:27 +0900
Subject: [PATCH] Fix `docker invalid-subcommand` regression

Starting with a3fe7d62b8274d69930286fb14653cccf37acadb,
`docker invalid-subcommand` did not exit with non-zero status.

Fix #1428

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
---
 cmd/docker/docker.go      |  3 +++
 cmd/docker/docker_test.go | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/cmd/docker/docker.go b/cmd/docker/docker.go
index a2bcd2a2cd..4b0c37c822 100644
--- a/cmd/docker/docker.go
+++ b/cmd/docker/docker.go
@@ -33,6 +33,9 @@ func newDockerCommand(dockerCli *command.DockerCli) *cobra.Command {
 		SilenceErrors:    true,
 		TraverseChildren: true,
 		Args:             noArgs,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return command.ShowHelp(dockerCli.Err())(cmd, args)
+		},
 		PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
 			// flags must be the top-level command flags, not cmd.Flags()
 			opts.Common.SetDefaultOptions(flags)
diff --git a/cmd/docker/docker_test.go b/cmd/docker/docker_test.go
index 7f7336b63e..7c6e4526f4 100644
--- a/cmd/docker/docker_test.go
+++ b/cmd/docker/docker_test.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bytes"
 	"io/ioutil"
 	"os"
 	"testing"
@@ -31,3 +32,20 @@ func TestExitStatusForInvalidSubcommandWithHelpFlag(t *testing.T) {
 	err := cmd.Execute()
 	assert.Error(t, err, "unknown help topic: invalid")
 }
+
+func TestExitStatusForInvalidSubcommand(t *testing.T) {
+	discard := ioutil.Discard
+	cmd := newDockerCommand(command.NewDockerCli(os.Stdin, discard, discard, false, nil))
+	cmd.SetArgs([]string{"invalid"})
+	err := cmd.Execute()
+	assert.Check(t, is.ErrorContains(err, "docker: 'invalid' is not a docker command."))
+}
+
+func TestVersion(t *testing.T) {
+	var b bytes.Buffer
+	cmd := newDockerCommand(command.NewDockerCli(os.Stdin, &b, &b, false, nil))
+	cmd.SetArgs([]string{"--version"})
+	err := cmd.Execute()
+	assert.NilError(t, err)
+	assert.Check(t, is.Contains(b.String(), "Docker version"))
+}