go-delve/delve · error

missing filename after -save flag

Error message

missing filename after -save flag

What it means

The 'breakpoints' (or related listing) command supports a '-save <file>' flag that writes the breakpoint list to a file. This error is returned when '-save' is the last argument so no filename follows it, detected by the `i+1 >= len(argv)` check.

Source

Thrown at pkg/terminal/command.go:1698

	fmt.Fprintf(t.stdout, "%s toggled at %s\n", formatBreakpointName(bp, true), t.formatBreakpointLocation(bp))
	return nil
}

func breakpoints(t *Term, ctx callContext, args string) error {
	// Parse arguments
	var showAll bool
	var saveFile string

	if args != "" {
		argv := strings.Fields(args)
	argsLoop:
		for i, arg := range argv {
			switch arg {
			case "-a":
				showAll = true
			case "-save":
				if i+1 >= len(argv) {
					return errors.New("missing filename after -save flag")
				}
				saveFile = argv[i+1]
				break argsLoop // Exit loop since we found -save and its argument
			}
		}
	}

	breakPoints, err := t.client.ListBreakpoints(showAll)
	if err != nil {
		return err
	}

	// If -save flag is provided, save breakpoints to file
	if saveFile != "" {
		file, err := os.Create(saveFile)
		if err != nil {
			return fmt.Errorf("failed to open file '%s': %w", saveFile, err)
		}

View on GitHub (pinned to a23773e6c3)

Solutions

1. Provide a filename: 'breakpoints -save breakpoints.json'
2. Quote paths containing spaces: '-save "/path/with spaces/bps.json"'
3. Check 'help breakpoints' for flag ordering

Example fix

// before
breakpoints -save
// after
breakpoints -save bps.json

i := slices.Index(argv, "-save")
if i != -1 && i+1 >= len(argv) {
	return errors.New("-save requires a filename argument")
}

if err := breakpointsCmd(...); err != nil && strings.Contains(err.Error(), "missing filename after -save flag") { /* re-run with an explicit filename */ }

When it happens

Trigger: Running 'breakpoints -save' without a trailing filename: the argsLoop sees '-save' at the last position and returns the error (pkg/terminal/command.go:1698).

Common situations: Truncated commands from shell history or scripts; forgetting that -save consumes the next token as the filename; quoting issues that swallow the filename argument.

Related errors

• address required
• argument of deferred must be a number greater than 0 (use 's
• too many arguments to restart
• Invalid next count
• too many arguments to trace

AI-assisted analysis of go-delve/delve@a23773e6c3 (2026-08-31). Data as JSON: /api/errors/2efc3460420d9995. Report an issue: GitHub.