network create: make --ipv6 optional

The API field `EnableIPv6` was marked as optional in our Swagger docs,
and its default value in the Go client came from that field being a
bool, thus defaulting to its zero value. That's not the case anymore.

This field is now a `*bool` as to let daemon's config define the default
value. IPv6 can still be enabled / disabled by explicitly specifying the
`--ipv6` flag when doing `docker network create`.

Signed-off-by: Albin Kerouanton <albinker@gmail.com>

cli/command/network/create.go

@@ -23,7 +23,7 @@ type createOptions struct {
 	driverOpts opts.MapOpts
 	labels     opts.ListOpts
 	internal   bool
-	ipv6       bool
+	ipv6       *bool
 	attachable bool
 	ingress    bool
 	configOnly bool
@@ -38,6 +38,7 @@ type createOptions struct {
 }
 
 func newCreateCommand(dockerCli command.Cli) *cobra.Command {
+	var ipv6 bool
 	options := createOptions{
 		driverOpts: *opts.NewMapOpts(nil, nil),
 		labels:     opts.NewListOpts(opts.ValidateLabel),
@@ -51,6 +52,11 @@ func newCreateCommand(dockerCli command.Cli) *cobra.Command {
 		Args:  cli.ExactArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			options.name = args[0]
+
+			if cmd.Flag("ipv6").Changed {
+				options.ipv6 = &ipv6
+			}
+
 			return runCreate(cmd.Context(), dockerCli, options)
 		},
 		ValidArgsFunction: completion.NoComplete,
@@ -61,7 +67,7 @@ func newCreateCommand(dockerCli command.Cli) *cobra.Command {
 	flags.VarP(&options.driverOpts, "opt", "o", "Set driver specific options")
 	flags.Var(&options.labels, "label", "Set metadata on a network")
 	flags.BoolVar(&options.internal, "internal", false, "Restrict external access to the network")
-	flags.BoolVar(&options.ipv6, "ipv6", false, "Enable IPv6 networking")
+	flags.BoolVar(&ipv6, "ipv6", false, "Enable or disable IPv6 networking")
 	flags.BoolVar(&options.attachable, "attachable", false, "Enable manual container attachment")
 	flags.SetAnnotation("attachable", "version", []string{"1.25"})
 	flags.BoolVar(&options.ingress, "ingress", false, "Create swarm routing-mesh network")
@@ -107,7 +113,7 @@ func runCreate(ctx context.Context, dockerCli command.Cli, options createOptions
 			Options: options.ipamOpt.GetAll(),
 		},
 		Internal:   options.internal,
-		EnableIPv6: &options.ipv6,
+		EnableIPv6: options.ipv6,
 		Attachable: options.attachable,
 		Ingress:    options.ingress,
 		Scope:      options.scope,

docs/reference/commandline/network_create.md

@@ -18,7 +18,7 @@ Create a network
 | `--ip-range`              | `stringSlice` |           | Allocate container ip from a sub-range                  |
 | `--ipam-driver`           | `string`      | `default` | IP Address Management Driver                            |
 | `--ipam-opt`              | `map`         | `map[]`   | Set IPAM driver specific options                        |
-| `--ipv6`                  |               |           | Enable IPv6 networking                                  |
+| `--ipv6`                  |               |           | Enable or disable IPv6 networking                       |
 | `--label`                 | `list`        |           | Set metadata on a network                               |
 | `-o`, `--opt`             | `map`         | `map[]`   | Set driver specific options                             |
 | `--scope`                 | `string`      |           | Control the network's scope                             |
@@ -170,7 +170,7 @@ flags used for the docker0 bridge:
 | `--gateway`  | -              | IPv4 or IPv6 Gateway for the master subnet |
 | `--ip-range` | `--fixed-cidr` | Allocate IPs from a range                  |
 | `--internal` | -              | Restrict external access to the network    |
-| `--ipv6`     | `--ipv6`       | Enable IPv6 networking                     |
+| `--ipv6`     | `--ipv6`       | Enable or disable IPv6 networking          |
 | `--subnet`   | `--bip`        | Subnet for network                         |
 
 For example, let's use `-o` or `--opt` options to specify an IP address binding