Fix help message flags on docker stack commands and sub-commands

PersistentPreRunE needs to be called within the help function to initialize all the flags (notably the orchestrator flag)
Add an e2e test as regression test

Signed-off-by: Silvin Lubecki <silvin.lubecki@docker.com>

cli/command/stack/cmd.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/docker/cli/cli"
 	"github.com/docker/cli/cli/command"
+	cliconfig "github.com/docker/cli/cli/config"
 	"github.com/docker/cli/cli/config/configfile"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
@@ -27,7 +28,11 @@ func NewStackCommand(dockerCli command.Cli) *cobra.Command {
 		Short: "Manage Docker stacks",
 		Args:  cli.NoArgs,
 		PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
-			orchestrator, err := getOrchestrator(dockerCli.ConfigFile(), cmd, dockerCli.Err())
+			configFile := dockerCli.ConfigFile()
+			if configFile == nil {
+				configFile = cliconfig.LoadDefaultConfigFile(dockerCli.Err())
+			}
+			orchestrator, err := getOrchestrator(configFile, cmd, dockerCli.Err())
 			if err != nil {
 				return err
 			}
@@ -42,9 +47,13 @@ func NewStackCommand(dockerCli command.Cli) *cobra.Command {
 		},
 	}
 	defaultHelpFunc := cmd.HelpFunc()
-	cmd.SetHelpFunc(func(cmd *cobra.Command, args []string) {
-		hideOrchestrationFlags(cmd, opts.orchestrator)
-		defaultHelpFunc(cmd, args)
+	cmd.SetHelpFunc(func(c *cobra.Command, args []string) {
+		if err := cmd.PersistentPreRunE(c, args); err != nil {
+			fmt.Fprintln(dockerCli.Err(), err)
+			return
+		}
+		hideOrchestrationFlags(c, opts.orchestrator)
+		defaultHelpFunc(c, args)
 	})
 	cmd.AddCommand(
 		newDeployCommand(dockerCli, &opts),

e2e/stack/help_test.go

@@ -0,0 +1,24 @@
+package stack
+
+import (
+	"fmt"
+	"testing"
+
+	"gotest.tools/golden"
+	"gotest.tools/icmd"
+)
+
+func TestStackDeployHelp(t *testing.T) {
+	t.Run("Swarm", func(t *testing.T) {
+		testStackDeployHelp(t, "swarm")
+	})
+	t.Run("Kubernetes", func(t *testing.T) {
+		testStackDeployHelp(t, "kubernetes")
+	})
+}
+
+func testStackDeployHelp(t *testing.T, orchestrator string) {
+	result := icmd.RunCommand("docker", "stack", "deploy", "--orchestrator", orchestrator, "--help")
+	result.Assert(t, icmd.Success)
+	golden.Assert(t, result.Stdout(), fmt.Sprintf("stack-deploy-help-%s.golden", orchestrator))
+}

e2e/stack/testdata/stack-deploy-help-kubernetes.golden

@@ -0,0 +1,14 @@
+
+Usage:	docker stack deploy [OPTIONS] STACK
+
+Deploy a new stack or update an existing stack
+
+Aliases:
+  deploy, up
+
+Options:
+  -c, --compose-file strings   Path to a Compose file, or "-" to read
+                               from stdin
+      --kubeconfig string      Kubernetes config file
+      --namespace string       Kubernetes namespace to use
+      --orchestrator string    Orchestrator to use (swarm|kubernetes|all)

e2e/stack/testdata/stack-deploy-help-swarm.golden

@@ -0,0 +1,19 @@
+
+Usage:	docker stack deploy [OPTIONS] STACK
+
+Deploy a new stack or update an existing stack
+
+Aliases:
+  deploy, up
+
+Options:
+      --bundle-file string     Path to a Distributed Application Bundle file
+  -c, --compose-file strings   Path to a Compose file, or "-" to read
+                               from stdin
+      --orchestrator string    Orchestrator to use (swarm|kubernetes|all)
+      --prune                  Prune services that are no longer referenced
+      --resolve-image string   Query the registry to resolve image digest
+                               and supported platforms
+                               ("always"|"changed"|"never") (default "always")
+      --with-registry-auth     Send registry authentication details to
+                               Swarm agents