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fix: complete subcommand flags after positional arguments #2426

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Merged
dearchap merged 1 commit into from
Sep 14, 2026
Merged

fix: complete subcommand flags after positional arguments #2426

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121 changes: 121 additions & 0 deletions completion_partial_regression_test.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,121 @@
package cli

import (
"bytes"
"context"
"os"
"reflect"
"strings"
"testing"
)

func partialCompletionCommand(output *bytes.Buffer, ran *bool) *Command {
command := func(name string) *Command {
return &Command{
Name: name,
Flags: []Flag{
&StringFlag{Name: "param-" + name + "-one"},
&StringFlag{Name: "param-" + name + "-two"},
&StringFlag{Name: "param-" + name + "-hidden", Hidden: true},
&BoolFlag{Name: "unrelated-" + name},
},
Action: func(context.Context, *Command) error { *ran = true; return nil },
}
}
root, child, nested := command("app"), command("sub"), command("nested")
root.Writer, root.ErrWriter = output, output
root.EnableShellCompletion = true
root.Commands = []*Command{child}
child.Commands = []*Command{nested}
return root
}

func TestPartialFlagCompletionAfterPositionalArgument(t *testing.T) {
originalArgs := os.Args
t.Cleanup(func() { os.Args = originalArgs })
for _, scope := range []struct {
name string
path []string
}{
{"app", nil},
{"sub", []string{"sub"}},
{"nested", []string{"sub", "nested"}},
} {
for _, positional := range [][]string{nil, {"value"}, {"first", "second"}} {
t.Run(scope.name+"/"+strings.Join(positional, "_"), func(t *testing.T) {
var output bytes.Buffer
ran := false
cmd := partialCompletionCommand(&output, &ran)
args := append([]string{"app"}, scope.path...)
args = append(args, positional...)
args = append(args, "--pa", completionFlag)
os.Args = args
if err := cmd.Run(context.Background(), args); err != nil {
t.Fatal(err)
}
want := "--param-" + scope.name + "-one\n--param-" + scope.name + "-two\n"
if got := output.String(); got != want {
t.Errorf("completion for %q = %q, want %q", args, got, want)
}
if ran {
t.Error("completion executed the command action")
}
})
}
}
}

func TestPartialFlagCompletionAfterDoubleDash(t *testing.T) {
originalArgs := os.Args
t.Cleanup(func() { os.Args = originalArgs })
for _, path := range [][]string{nil, {"sub"}, {"sub", "nested"}} {
t.Run(strings.Join(path, "/"), func(t *testing.T) {
var output bytes.Buffer
ran := false
cmd := partialCompletionCommand(&output, &ran)
args := append([]string{"app"}, path...)
args = append(args, "--", "--pa", completionFlag)
os.Args = args
if err := cmd.Run(context.Background(), args); err != nil {
t.Fatal(err)
}
if output.Len() != 0 || ran {
t.Errorf("completion after --: output=%q action=%v", output.String(), ran)
}
})
}
}

func TestPartialFlagCustomCompletionArgs(t *testing.T) {
var output bytes.Buffer
ran := false
cmd := partialCompletionCommand(&output, &ran)
var got []string
cmd.Commands[0].ShellComplete = func(_ context.Context, cmd *Command) {
got = append([]string(nil), cmd.Args().Slice()...)
}
args := []string{"app", "sub", "value", "--pa", completionFlag}
if err := cmd.Run(context.Background(), args); err != nil {
t.Fatal(err)
}
if want := []string{"value", "--pa"}; !reflect.DeepEqual(got, want) {
t.Errorf("custom completion args = %q, want %q", got, want)
}
if ran {
t.Error("custom completion executed the action")
}
}

func TestPartialFlagCompletionDisabled(t *testing.T) {
var output bytes.Buffer
ran := false
cmd := partialCompletionCommand(&output, &ran)
cmd.EnableShellCompletion = false
args := []string{"app", "sub", "value", "--pa", completionFlag}
if err := cmd.Run(context.Background(), args); err == nil {
t.Fatal("disabled completion accepted an undefined flag")
}
if ran || strings.Contains(output.String(), "--param-sub-one\n--param-sub-two\n") {
t.Fatalf("disabled completion: output=%q action=%v", output.String(), ran)
}
}
11 changes: 6 additions & 5 deletions help.go
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Original file line number Diff line number Diff line change
Expand Up @@ -257,12 +257,13 @@ func DefaultCompleteWithFlags(ctx context.Context, cmd *Command) {
}
argsLen := len(args)
lastArg := ""
// parent command will have --generate-shell-completion so we need
// to account for that
if argsLen > 1 {
lastArg = args[argsLen-2]
} else if argsLen > 0 {
// os.Args retains the completion marker, but a child's parsed arguments
// have already had it removed.
if argsLen > 0 {
lastArg = args[argsLen-1]
if lastArg == completionFlag && argsLen > 1 {
lastArg = args[argsLen-2]
}
}

if lastArg == completionFlag {
Expand Down