✨ feat(cli): Show hint message when file completion not applicable to subcommand by vitorfloriano · Pull Request #5587 · kubernetes-sigs/kubebuilder

vitorfloriano · 2026-04-07T02:58:47Z

This PR adds ActiveHelp to the init, edit, alpha generate, alpha update, create api and create webhook subcommands.

Now, when hitting TAB on subcommands that don't take files as arguments, the cli will show a hint message (ActiveHelp) on how to list flags instead of showing file completions.

👎🏻 Current behavior:

$ kubebuilder create api <TAB>
AGENTS.md           designs/            go.mod              Makefile            RELEASE.md          test.sh
bin/                docs/               go.sum              netlify.toml        roadmap/            VERSIONING.md
build/              .git/               hack/               OWNERS              SECURITY_CONTACTS   .yamllint
code-of-conduct.md  .github/            internal/           OWNERS_ALIASES      test/               .yamllint-helm
CONTRIBUTING.md     .gitignore          LICENSE             pkg/                testdata/           
DESIGN.md           .golangci.yml       main.go             README.md           test_e2e.sh

👍🏻 New behavior:

$ kubebuilder create api <TAB>
Type '--' and press TAB to list flags

Note

This is just a first iteration and can be expanded upon, as we see fit.

Relates to #5446

k8s-ci-robot · 2026-04-07T02:58:54Z

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vitorfloriano · 2026-04-07T16:06:37Z

+	scaffoldCmd.ValidArgsFunction = func(cmd *cobra.Command, args []string, toComplete string) ([]cobra.Completion, cobra.ShellCompDirective) {
+		completions := []cobra.Completion{}
+		if len(args) == 0 && toComplete == "" {
+			completions = cobra.AppendActiveHelp(completions, "Type '--' and press TAB to list flags")


Or we could do something like:

Suggested change

completions = cobra.AppendActiveHelp(completions, "Type '--' and press TAB to list flags")

completions = cobra.AppendActiveHelp(completions, "Type '--help' to get help. Type '--' and press TAB to list flags.")

Or:

Suggested change

completions = cobra.AppendActiveHelp(completions, "Type '--' and press TAB to list flags")

completions = cobra.AppendActiveHelp(completions, "Type '--' and press TAB to list flags. Type '--help' to show help.")

I think, if possible we need to check how to solve in the CLI without need to implement each command.

I think, if possible we need to check how to solve in the CLI without need to implement each command.

ValidArgsFunction is a field in the cobra.Command struct. It's like Use, Run, PreRunE and alike. It needs to be implemented in each command.

There may be way to work around this and make it global, but I don't think that's very idiomatic and will possibly have side-effects.

When hitting TAB on subcommands that don't take files as arguments, the cli will show a hint message (ActiveHelp) on how to list flags instead of showing file completions.

vitorfloriano · 2026-04-07T17:26:11Z

/retest

Copilot

Pull request overview

Adds Cobra ActiveHelp-backed shell completion hints to several Kubebuilder subcommands so that pressing TAB on commands that don’t take file arguments shows a guidance message instead of suggesting filesystem entries.

Changes:

Set ValidArgsFunction to append an ActiveHelp hint (Type '--' and press TAB to list flags) when appropriate.
Disable file completion via cobra.ShellCompDirectiveNoFileComp for the affected subcommands.
Apply the behavior across init, edit, create api, create webhook, alpha generate, alpha update (and also version).

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
pkg/cli/api.go	Adds ActiveHelp hint + disables file completion for `kubebuilder create api`.
pkg/cli/webhook.go	Adds ActiveHelp hint + disables file completion for `kubebuilder create webhook`.
pkg/cli/init.go	Adds ActiveHelp hint + disables file completion for `kubebuilder init`.
pkg/cli/edit.go	Adds ActiveHelp hint + disables file completion for `kubebuilder edit`.
pkg/cli/version.go	Adds ActiveHelp hint + disables file completion for `kubebuilder version`.
internal/cli/alpha/generate.go	Adds ActiveHelp hint + disables file completion for `kubebuilder alpha generate`.
internal/cli/alpha/update.go	Adds ActiveHelp hint + disables file completion for `kubebuilder alpha update`.

Copilot · 2026-04-07T18:50:20Z

+		toComplete string,
+	) ([]cobra.Completion, cobra.ShellCompDirective) {
+		completions := []cobra.Completion{}
+		if len(args) == 0 && toComplete == "" {


The ActiveHelp hint is only appended when toComplete == "". If the user types any partial token before TAB (e.g. kubebuilder create api x<TAB>), this returns no completions + ShellCompDirectiveNoFileComp, so nothing is shown and the hint is lost. Consider showing the hint whenever len(args) == 0 (or at least when len(args) == 0 and the token isn't a flag) so the UX is consistent.

Suggested change

if len(args) == 0 && toComplete == "" {

if len(args) == 0 && (toComplete == "" || toComplete[0] != '-') {

Copilot · 2026-04-07T18:50:21Z

+		toComplete string,
+	) ([]cobra.Completion, cobra.ShellCompDirective) {
+		completions := []cobra.Completion{}
+		if len(args) == 0 && toComplete == "" {


The ActiveHelp hint is only appended when toComplete == "". If the user types any partial token before TAB, this returns no completions + ShellCompDirectiveNoFileComp, so nothing is shown. Consider showing the hint whenever len(args) == 0 (or when the token isn't a flag) so the UX remains helpful in more cases.

Suggested change

if len(args) == 0 && toComplete == "" {

if len(args) == 0 && (toComplete == "" || toComplete[0] != '-') {

Copilot · 2026-04-07T18:50:21Z

+		toComplete string,
+	) ([]cobra.Completion, cobra.ShellCompDirective) {
+		completions := []cobra.Completion{}
+		if len(args) == 0 && toComplete == "" {


The ActiveHelp hint is only appended when toComplete == "". If the user has started typing an argument before pressing TAB, completion will return nothing and the hint won't appear. Consider appending ActiveHelp whenever len(args) == 0 (or when the token isn't a flag) so users still get guidance.

Suggested change

if len(args) == 0 && toComplete == "" {

if len(args) == 0 && (toComplete == "" || !strings.HasPrefix(toComplete, "-")) {

Copilot · 2026-04-07T18:50:22Z

+		toComplete string,
+	) ([]cobra.Completion, cobra.ShellCompDirective) {
+		completions := []cobra.Completion{}
+		if len(args) == 0 && toComplete == "" {


The ActiveHelp hint is only appended when toComplete == "". If the user starts typing a token and then presses TAB, this returns no completions + ShellCompDirectiveNoFileComp, so no hint is displayed. Consider showing the hint whenever len(args) == 0 (or when the token isn't a flag) to keep the behavior consistent.

Suggested change

if len(args) == 0 && toComplete == "" {

if len(args) == 0 && (toComplete == "" || toComplete[0] != '-') {

Copilot · 2026-04-07T18:50:22Z

+		completions := []cobra.Completion{}
+		if len(args) == 0 && toComplete == "" {


The ActiveHelp hint is only appended when toComplete == "". If the user starts typing an argument before TAB, completion will return nothing and the hint won't show. Consider appending ActiveHelp whenever len(args) == 0 (or when the token isn't a flag) for a more consistent UX.

Suggested change

completions := []cobra.Completion{}

if len(args) == 0 && toComplete == "" {

_ = toComplete

completions := []cobra.Completion{}

if len(args) == 0 {

Copilot · 2026-04-07T18:50:22Z

+		toComplete string,
+	) ([]cobra.Completion, cobra.ShellCompDirective) {
+		completions := []cobra.Completion{}
+		if len(args) == 0 && toComplete == "" {


The ActiveHelp hint is only appended when toComplete == "". If the user types a partial token before TAB, this will return no completions + ShellCompDirectiveNoFileComp and show nothing. Consider appending ActiveHelp whenever len(args) == 0 (or when the token isn't a flag) so guidance is still shown.

Suggested change

if len(args) == 0 && toComplete == "" {

if len(args) == 0 && (toComplete == "" || toComplete[0] != '-') {

Copilot · 2026-04-07T18:50:23Z

+		toComplete string,
+	) ([]cobra.Completion, cobra.ShellCompDirective) {
+		completions := []cobra.Completion{}
+		if len(args) == 0 && toComplete == "" {


The ActiveHelp hint is only appended when toComplete == "". If the user starts typing a token before pressing TAB, this returns no completions + ShellCompDirectiveNoFileComp, so no hint is displayed. Consider appending ActiveHelp whenever len(args) == 0 (or when the token isn't a flag) so users still get guidance.

Suggested change

if len(args) == 0 && toComplete == "" {

if len(args) == 0 && (toComplete == "" || toComplete[0] != '-') {

Copilot · 2026-04-07T18:50:23Z

+	// Show hint message on how to list flags instead of showing file completion for
+	// commands that don't take files as arguments
+	cmd.ValidArgsFunction = func(
+		_ *cobra.Command,
+		args []string,
+		toComplete string,
+	) ([]cobra.Completion, cobra.ShellCompDirective) {
+		completions := []cobra.Completion{}
+		if len(args) == 0 && toComplete == "" {
+			completions = cobra.AppendActiveHelp(completions, "Type '--' and press TAB to list flags")
+		}
+		return completions, cobra.ShellCompDirectiveNoFileComp
+	}


This same ValidArgsFunction block (including the literal hint string) is duplicated across multiple commands/files in this PR. To keep behavior and wording consistent over time, consider extracting this into a small helper (e.g. a function that sets the ValidArgsFunction) and/or a shared const for the hint message.

Copilot · 2026-04-07T18:50:23Z

+	// Show hint message on how to list flags instead of showing file completion for
+	// commands that don't take files as arguments
+	cmd.ValidArgsFunction = func(
+		_ *cobra.Command,
+		args []string,
+		toComplete string,
+	) ([]cobra.Completion, cobra.ShellCompDirective) {
+		completions := []cobra.Completion{}
+		if len(args) == 0 && toComplete == "" {
+			completions = cobra.AppendActiveHelp(completions, "Type '--' and press TAB to list flags")
+		}
+		return completions, cobra.ShellCompDirectiveNoFileComp
+	}


PR description lists the subcommands being updated, but version is also modified here. Either include version in the description (if intended) or drop this change to keep the scope aligned with the PR narrative.

k8s-ci-robot · 2026-04-20T01:04:06Z

PR needs rebase.

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k8s-ci-robot · 2026-04-30T15:44:27Z

@vitorfloriano: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-kubebuilder-e2e-k8s-1-36-0	`bb4ddcb`	link	true	`/test pull-kubebuilder-e2e-k8s-1-36-0`

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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k8s-ci-robot requested review from camilamacedo86 and varshaprasad96 April 7, 2026 02:58

k8s-ci-robot added size/M Denotes a PR that changes 30-99 lines, ignoring generated files. cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. labels Apr 7, 2026

vitorfloriano commented Apr 7, 2026

View reviewed changes

feat(cli): show hint when file completion not applicable

bb4ddcb

When hitting TAB on subcommands that don't take files as arguments, the cli will show a hint message (ActiveHelp) on how to list flags instead of showing file completions.

vitorfloriano force-pushed the show-active-help branch from fa5970b to bb4ddcb Compare April 7, 2026 16:53

camilamacedo86 requested a review from Copilot April 7, 2026 18:46

Copilot started reviewing on behalf of camilamacedo86 April 7, 2026 18:46 View session

Copilot AI reviewed Apr 7, 2026

View reviewed changes

vitorfloriano marked this pull request as draft April 8, 2026 11:57

k8s-ci-robot added the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label Apr 8, 2026

k8s-ci-robot added the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Apr 20, 2026

	completions = cobra.AppendActiveHelp(completions, "Type '--' and press TAB to list flags")
	completions = cobra.AppendActiveHelp(completions, "Type '--help' to get help. Type '--' and press TAB to list flags.")

	if len(args) == 0 && toComplete == "" {
	if len(args) == 0 && (toComplete == "" \|\| toComplete[0] != '-') {

		completions := []cobra.Completion{}
		if len(args) == 0 && toComplete == "" {

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vitorfloriano commented Apr 7, 2026 •

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