fix: preserve incomplete short groups for shell completion by kimjooyoon · Pull Request #2485 · urfave/cli

kimjooyoon · 2026-10-22T00:07:22Z

What type of PR is this?

bug

What this PR does / why we need it:

With UseShortOptionHandling enabled, custom shell completion loses an unfinished grouped flag from cmd.Args(). For example, declare boolean a and string b, then run:

cmd.Run(ctx, []string{"app", "value", "-ab", "--generate-shell-completion"})

A ShellComplete callback reading cmd.Args().Slice() currently receives only ["value"]. After this change it receives ["value", "-ab"], matching the existing handling of an unfinished single flag such as -b.

command_parse.go retains the unparsed tail during shell completion when a short group contains an unknown flag, has a value-taking flag that is not last (-ba), or its final value-taking flag has no value yet. Normal invocations still return their original errors. Complete groups, including an explicit empty value (-ab=), remain consumed normally.

TestCommand_Run_CustomShellCompleteAcceptsMalformedFlags covers each of these groups, and a complete group that is still consumed during completion.

Which issue(s) this PR fixes:

Independently reproduced on main 10f69fd3c38de86a3bc17810dcb7f818b494f027; no existing matching issue or open PR found in the search before submission.

Special notes for your reviewer:

Authored and tested with a Codex agent on behalf of kimjooyoon. This change adds no dependency and changes no public API. It extends the existing single-flag completion behavior to grouped short flags.

Testing

Rebased onto main 63c2771c704accdd5f07eb40006c918da9687372:

The new -an, -ax and -na cases fail on main and pass with the fix.
go test ./..., go test -tags urfave_cli_no_template ./..., go test -race ./..., go vet ./... and golangci-lint pass.

Release Notes

Preserve unfinished grouped short flags in arguments passed to custom shell completion callbacks.

Authored with Codex. Keep pending grouped tokens available to custom completion callbacks, matching the existing single-flag behavior. Signed-off-by: Eng Zer Jun <[email protected]>

Juneezee

Thanks! This also fixes the default completer on a subcommand: with a bool flag all aliased a, app sub -al<TAB> used to suggest subcommands and now suggests --all.

I rebased onto main and pushed two changes:

Completion now also keeps a group whose value-taking flag is not last, such as -ba. Before this, with flags a (bool), b (string) and batch (bool), app sub -ba<TAB> suggested subcommands instead of --batch, and a custom callback got []:

cli/command_parse.go

Lines 275 to 284 in f529377

    
           } else { 
        
           	// only the last flag of a group can take an argument, so a flag 
        
           	// that needs one has nothing to read it from here 
        
           	tracef("processing flag.5 (fName=%[1]q)", string(c)) 
        
           	if cmd.Root().shellCompletion { 
        
           		posArgs = append(posArgs, rargs...) 
        
           		return &stringSliceArgs{posArgs}, nil 
        
           	} 
        
           	return &stringSliceArgs{posArgs}, fmt.Errorf("%s%s", argumentNotProvidedErrMsg, string(c)) 
        
           }

I replaced completion_short_group_test.go with four cases in the existing completion test. Most of the old file re-tested normal group parsing that other tests already cover:

cli/command_test.go

Lines 603 to 617 in f529377

    
           func TestCommand_Run_CustomShellCompleteAcceptsMalformedFlags(t *testing.T) { 
        
           	cases := []struct { 
        
           		testArgs    *stringSliceArgs 
        
           		expectedOut string 
        
           	}{ 
        
           		{testArgs: &stringSliceArgs{v: []string{"--undefined"}}, expectedOut: "found 1 args"}, 
        
           		{testArgs: &stringSliceArgs{v: []string{"--number"}}, expectedOut: "found 1 args"}, 
        
           		{testArgs: &stringSliceArgs{v: []string{"--number", "forty-two"}}, expectedOut: "found 0 args"}, 
        
           		{testArgs: &stringSliceArgs{v: []string{"--number", "42"}}, expectedOut: "found 0 args"}, 
        
           		{testArgs: &stringSliceArgs{v: []string{"--number", "42", "newArg"}}, expectedOut: "found 1 args"}, 
        
           		{testArgs: &stringSliceArgs{v: []string{"-an"}}, expectedOut: "found 1 args"}, 
        
           		{testArgs: &stringSliceArgs{v: []string{"-ax"}}, expectedOut: "found 1 args"}, 
        
           		{testArgs: &stringSliceArgs{v: []string{"-na"}}, expectedOut: "found 1 args"}, 
        
           		{testArgs: &stringSliceArgs{v: []string{"-an", "42"}}, expectedOut: "found 0 args"}, 
        
           	}

I also updated the PR description to match.

kimjooyoon · 2026-10-25T06:16:56Z

Thanks for catching the non-final value-taking case and consolidating the tests. I verified f529377 with root-only UseShortOptionHandling on a subcommand: default completion returns --all for -al and --batch for -ba, and custom callbacks receive the exact original tokens. Action stays uncalled in all four cases. The older submitted revision already handled -al; your additional guard closes the -ba gap in my original change.

kimjooyoon requested a review from a team as a code owner October 22, 2026 00:07

kimjooyoon mentioned this pull request Oct 22, 2026

Contribution evidence ledger — 2026-10-22, part 1 kimjooyoon/gooo-language-bridge#1

Closed

fix: preserve incomplete short groups for shell completion

f529377

Authored with Codex. Keep pending grouped tokens available to custom completion callbacks, matching the existing single-flag behavior. Signed-off-by: Eng Zer Jun <[email protected]>

Juneezee force-pushed the fix/completion-short-groups branch from 5dbdb10 to f529377 Compare October 25, 2026 05:50

Juneezee approved these changes Oct 25, 2026

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kimjooyoon mentioned this pull request Oct 25, 2026

Contribution evidence ledger — continuation after #24 kimjooyoon/gooo-language-bridge#30

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Juneezee merged commit a715e62 into urfave:main Oct 25, 2026
9 checks passed

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fix: preserve incomplete short groups for shell completion - #2485

fix: preserve incomplete short groups for shell completion#2485
Juneezee merged 1 commit into
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kimjooyoon:fix/completion-short-groups

kimjooyoon commented Oct 22, 2026 •

edited by Juneezee

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	} else {
	// only the last flag of a group can take an argument, so a flag
	// that needs one has nothing to read it from here
	tracef("processing flag.5 (fName=%[1]q)", string(c))
	if cmd.Root().shellCompletion {
	posArgs = append(posArgs, rargs...)
	return &stringSliceArgs{posArgs}, nil
	}
	return &stringSliceArgs{posArgs}, fmt.Errorf("%s%s", argumentNotProvidedErrMsg, string(c))
	}

	func TestCommand_Run_CustomShellCompleteAcceptsMalformedFlags(t *testing.T) {
	cases := []struct {
	testArgs *stringSliceArgs
	expectedOut string
	}{
	{testArgs: &stringSliceArgs{v: []string{"--undefined"}}, expectedOut: "found 1 args"},
	{testArgs: &stringSliceArgs{v: []string{"--number"}}, expectedOut: "found 1 args"},
	{testArgs: &stringSliceArgs{v: []string{"--number", "forty-two"}}, expectedOut: "found 0 args"},
	{testArgs: &stringSliceArgs{v: []string{"--number", "42"}}, expectedOut: "found 0 args"},
	{testArgs: &stringSliceArgs{v: []string{"--number", "42", "newArg"}}, expectedOut: "found 1 args"},
	{testArgs: &stringSliceArgs{v: []string{"-an"}}, expectedOut: "found 1 args"},
	{testArgs: &stringSliceArgs{v: []string{"-ax"}}, expectedOut: "found 1 args"},
	{testArgs: &stringSliceArgs{v: []string{"-na"}}, expectedOut: "found 1 args"},
	{testArgs: &stringSliceArgs{v: []string{"-an", "42"}}, expectedOut: "found 0 args"},
	}

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Special notes for your reviewer:

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kimjooyoon commented Oct 22, 2026 •

edited by Juneezee

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