Carry #11858

Continues 11858 by:
- Making sure the exit code is always zero when we ask for help
- Making sure the exit code isn't zero when we print help on error cases
- Making sure both short and long usage go to the same stream (stdout vs stderr)
- Making sure all docker commands support --help
- Test that all cmds send --help to stdout, exit code 0, show full usage, no blank lines at end
- Test that all cmds (that support it) show short usage on bad arg to stderr, no blank line at end
- Test that all cmds complain about a bad option, no blank line at end
- Test that docker (w/o subcmd) does the same stuff mentioned above properly

Signed-off-by: Doug Davis <dug@us.ibm.com>

api/client/cli.go

@@ -8,7 +8,6 @@ import (
 	"io"
 	"net"
 	"net/http"
-	"os"
 	"path/filepath"
 	"reflect"
 	"strings"
@@ -98,7 +97,7 @@ func (cli *DockerCli) Cmd(args ...string) error {
 	if len(args) > 0 {
 		method, exists := cli.getMethod(args[0])
 		if !exists {
-			return fmt.Errorf("docker: '%s' is not a docker command. See 'docker --help'.", args[0])
+			return fmt.Errorf("docker: '%s' is not a docker command.\nSee 'docker --help'.", args[0])
 		}
 		return method(args[1:]...)
 	}
@@ -124,15 +123,13 @@ func (cli *DockerCli) Subcmd(name, signature, description string, exitOnError bo
 	flags.Usage = func() {
 		flags.ShortUsage()
 		flags.PrintDefaults()
-		os.Exit(0)
 	}
 	flags.ShortUsage = func() {
 		options := ""
 		if flags.FlagCountUndeprecated() > 0 {
 			options = " [OPTIONS]"
 		}
-		fmt.Fprintf(cli.out, "\nUsage: docker %s%s%s\n\n%s\n\n", name, options, signature, description)
-		flags.SetOutput(cli.out)
+		fmt.Fprintf(flags.Out(), "\nUsage: docker %s%s%s\n\n%s\n", name, options, signature, description)
 	}
 	return flags
 }

api/client/info.go

@@ -15,7 +15,7 @@ import (
 func (cli *DockerCli) CmdInfo(args ...string) error {
 	cmd := cli.Subcmd("info", "", "Display system-wide information", true)
 	cmd.Require(flag.Exact, 0)
-	cmd.ParseFlags(args, false)
+	cmd.ParseFlags(args, true)
 
 	rdr, _, err := cli.call("GET", "/info", nil, nil)
 	if err != nil {

api/client/logout.go

@@ -16,7 +16,7 @@ func (cli *DockerCli) CmdLogout(args ...string) error {
 	cmd := cli.Subcmd("logout", "[SERVER]", "Log out from a Docker registry, if no server is\nspecified \""+registry.IndexServerAddress()+"\" is the default.", true)
 	cmd.Require(flag.Max, 1)
 
-	cmd.ParseFlags(args, false)
+	cmd.ParseFlags(args, true)
 	serverAddress := registry.IndexServerAddress()
 	if len(cmd.Args()) > 0 {
 		serverAddress = cmd.Arg(0)

api/client/pause.go

@@ -12,7 +12,7 @@ import (
 func (cli *DockerCli) CmdPause(args ...string) error {
 	cmd := cli.Subcmd("pause", "CONTAINER [CONTAINER...]", "Pause all processes within a container", true)
 	cmd.Require(flag.Min, 1)
-	cmd.ParseFlags(args, false)
+	cmd.ParseFlags(args, true)
 
 	var errNames []string
 	for _, name := range cmd.Args() {

api/client/unpause.go

@@ -12,7 +12,7 @@ import (
 func (cli *DockerCli) CmdUnpause(args ...string) error {
 	cmd := cli.Subcmd("unpause", "CONTAINER [CONTAINER...]", "Unpause all processes within a container", true)
 	cmd.Require(flag.Min, 1)
-	cmd.ParseFlags(args, false)
+	cmd.ParseFlags(args, true)
 
 	var errNames []string
 	for _, name := range cmd.Args() {

api/client/version.go

@@ -20,7 +20,7 @@ func (cli *DockerCli) CmdVersion(args ...string) error {
 	cmd := cli.Subcmd("version", "", "Show the Docker version information.", true)
 	cmd.Require(flag.Exact, 0)
 
-	cmd.ParseFlags(args, false)
+	cmd.ParseFlags(args, true)
 
 	if dockerversion.VERSION != "" {
 		fmt.Fprintf(cli.out, "Client version: %s\n", dockerversion.VERSION)