cli/command/completion: change Platforms to return a cobra.CompletionFunc

It's adding a slight indirection by constructing a function when called,
but makes the completion functions more consistent, the signature easier
to read, and making the return type a [cobra.CompletionFunc] makes it
more transparent what it's intended for, and helps discovery of functions
that provide completion.

[cobra.CompletionFunc]: https://pkg.go.dev/github.com/spf13/cobra#CompletionFunc

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/command/completion/functions.go

@@ -178,7 +178,7 @@ var commonPlatforms = []string{
 //     but don't have wide adoption (and no support), such as loong64, mipsXXX,
 //     ppc64 (non-le) to prevent confusion.
 func Platforms() cobra.CompletionFunc {
-	return func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+	return func(_ *cobra.Command, _ []string, _ string) ([]string, cobra.ShellCompDirective) {
 		return commonPlatforms, cobra.ShellCompDirectiveNoFileComp
 	}
 }

cli/command/container/completion.go

@@ -130,7 +130,7 @@ func addCompletions(cmd *cobra.Command, dockerCLI completion.APIClientProvider)
 	_ = cmd.RegisterFlagCompletionFunc("log-opt", completeLogOpt)
 	_ = cmd.RegisterFlagCompletionFunc("network", completion.NetworkNames(dockerCLI))
 	_ = cmd.RegisterFlagCompletionFunc("pid", completePid(dockerCLI))
-	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
+	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms())
 	_ = cmd.RegisterFlagCompletionFunc("pull", completion.FromList(PullImageAlways, PullImageMissing, PullImageNever))
 	_ = cmd.RegisterFlagCompletionFunc("restart", completeRestartPolicies)
 	_ = cmd.RegisterFlagCompletionFunc("security-opt", completeSecurityOpt)

cli/command/container/create.go

@@ -88,7 +88,7 @@ func newCreateCommand(dockerCLI command.Cli) *cobra.Command {
 
 	// TODO(thaJeztah): consider adding platform as "image create option" on containerOptions
 	addPlatformFlag(flags, &options.platform)
-	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
+	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms())
 
 	flags.BoolVar(&options.untrusted, "disable-content-trust", !dockerCLI.ContentTrustEnabled(), "Skip image verification")
 	copts = addFlags(flags)

cli/command/image/build.go

@@ -157,7 +157,7 @@ func newBuildCommand(dockerCLI command.Cli) *cobra.Command {
 	flags.SetAnnotation("squash", "experimental", nil)
 	flags.SetAnnotation("squash", "version", []string{"1.25"})
 
-	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
+	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms())
 
 	return cmd
 }

cli/command/image/history.go

@@ -52,7 +52,7 @@ func newHistoryCommand(dockerCLI command.Cli) *cobra.Command {
 	flags.StringVar(&opts.platform, "platform", "", `Show history for the given platform. Formatted as "os[/arch[/variant]]" (e.g., "linux/amd64")`)
 	_ = flags.SetAnnotation("platform", "version", []string{"1.48"})
 
-	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
+	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms())
 	return cmd
 }
 

cli/command/image/import.go

@@ -49,7 +49,7 @@ func newImportCommand(dockerCLI command.Cli) *cobra.Command {
 	flags.VarP(&options.changes, "change", "c", "Apply Dockerfile instruction to the created image")
 	flags.StringVarP(&options.message, "message", "m", "", "Set commit message for imported image")
 	addPlatformFlag(flags, &options.platform)
-	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
+	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms())
 
 	return cmd
 }

cli/command/image/inspect.go

@@ -52,7 +52,7 @@ If the image or the server is not multi-platform capable, the command will error
 'os[/arch[/variant]]': Explicit platform (eg. linux/amd64)`)
 	flags.SetAnnotation("platform", "version", []string{"1.49"})
 
-	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
+	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms())
 	return cmd
 }
 

cli/command/image/load.go

@@ -48,7 +48,7 @@ func newLoadCommand(dockerCLI command.Cli) *cobra.Command {
 	flags.StringSliceVar(&opts.platform, "platform", []string{}, `Load only the given platform(s). Formatted as a comma-separated list of "os[/arch[/variant]]" (e.g., "linux/amd64,linux/arm64/v8").`)
 	_ = flags.SetAnnotation("platform", "version", []string{"1.48"})
 
-	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
+	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms())
 	return cmd
 }
 

cli/command/image/pull.go

@@ -52,7 +52,7 @@ func newPullCommand(dockerCLI command.Cli) *cobra.Command {
 	addPlatformFlag(flags, &opts.platform)
 	flags.BoolVar(&opts.untrusted, "disable-content-trust", !dockerCLI.ContentTrustEnabled(), "Skip image verification")
 
-	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
+	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms())
 
 	return cmd
 }

cli/command/image/push.go

@@ -69,7 +69,7 @@ Image index won't be pushed, meaning that other manifests, including attestation
 'os[/arch[/variant]]': Explicit platform (eg. linux/amd64)`)
 	flags.SetAnnotation("platform", "version", []string{"1.46"})
 
-	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
+	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms())
 
 	return cmd
 }

cli/command/image/remove.go

@@ -47,7 +47,7 @@ func newRemoveCommand(dockerCLI command.Cli) *cobra.Command {
 	flags.StringSliceVar(&options.platforms, "platform", nil, `Remove only the given platform variant. Formatted as "os[/arch[/variant]]" (e.g., "linux/amd64")`)
 	_ = flags.SetAnnotation("platform", "version", []string{"1.50"})
 
-	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
+	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms())
 	return cmd
 }
 

cli/command/image/save.go

@@ -47,7 +47,7 @@ func newSaveCommand(dockerCLI command.Cli) *cobra.Command {
 	flags.StringSliceVar(&opts.platform, "platform", []string{}, `Save only the given platform(s). Formatted as a comma-separated list of "os[/arch[/variant]]" (e.g., "linux/amd64,linux/arm64/v8")`)
 	_ = flags.SetAnnotation("platform", "version", []string{"1.48"})
 
-	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
+	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms())
 	return cmd
 }