What causes "wrong number of arguments to "config"" in go-delve/delve?

Use 'config -list' to show current configuration.

wrong number of arguments to "config"

Error message

wrong number of arguments to "config"

What it means

configureCmd handles the 'config' terminal command. It accepts '-list', '-save', or a '<key> <value>' assignment handled by configureSet. An empty argument matches none of these and yields 'wrong number of arguments to "config"', since bare 'config' is not a supported form (use 'config -list' to see settings).

Source

Thrown at pkg/terminal/config.go:21

import (
	"errors"
	"fmt"
	"reflect"
	"strings"
	"text/tabwriter"

	"github.com/go-delve/delve/pkg/config"
)

func configureCmd(t *Term, ctx callContext, args string) error {
	t.substitutePathRulesCache = nil
	switch args {
	case "-list":
		return configureList(t)
	case "-save":
		return config.SaveConfig(t.conf)
	case "":
		return errors.New("wrong number of arguments to \"config\"")
	default:
		err := configureSet(t, args)
		if err != nil {
			return err
		}
		if t.client != nil { // only happens in tests
			lcfg := t.loadConfig()
			t.client.SetReturnValuesLoadConfig(&lcfg)
			t.updateConfig()
		}
		return nil
	}
}

func configureList(t *Term) error {
	w := new(tabwriter.Writer)
	w.Init(t.stdout, 0, 8, 1, ' ', 0)
	config.ConfigureList(w, t.conf, "yaml")

View on GitHub (pinned to a23773e6c3)

Solutions

Use 'config -list' to show current configuration.
Use 'config -save' to persist the configuration.
Set a value with 'config <key> <value>', e.g. 'config max-string-len 200'.
Run 'help config' for the exact syntax.

Example fix

// before
config
// after
config -list

Defensive patterns

Strategy: validation

Validate before calling

if strings.TrimSpace(args) == "" { return errors.New("config requires -list, -save, or '<key> <value>'") }

Type guard

func validConfigArgs(args string) bool {
    switch strings.TrimSpace(args) {
    case "", "-list", "-save":
        return strings.TrimSpace(args) != ""
    }
    return strings.Contains(strings.TrimSpace(args), " ") // key value pair
}

Try / catch

// wrapping configureCmd in tests
if err := configureCmd(t, ctx, args); err != nil {
    t.Fatalf("config %q failed: %v", args, err)
}

Prevention

Use 'config -list' instead of bare 'config' to view settings.
Always pass a key and value together when setting, e.g. 'config substitute-path /a /b'.
In tests, never invoke configureCmd with an empty args string; assert on the expected error or supply valid args.

When it happens

Trigger: Running 'config' with no arguments at all in the terminal (or via the test path assertNoErrorConfigureCmd/TestConfig where args is empty).

Common situations: Users typing 'config' expecting an interactive listing, unaware that listing requires 'config -list'; or empty arguments after shell quoting strips content.

Related errors

AI-assisted analysis of go-delve/delve@a23773e6c3 (2026-08-31). Data as JSON: /api/errors/a694149157f79102. Report an issue: GitHub.