go-delve/delve · error

too many arguments to trace

Error message

too many arguments to trace

What it means

The 'trace'/'tracepoint' terminal command in Delve is being used with a positional argument while inside an 'on <bp>' breakpoint context. In 'on' mode the command takes no arguments because it only toggles the tracepoint flag on the existing breakpoint; extra text cannot be interpreted, so Delve rejects it with this error.

Source

Thrown at pkg/terminal/command.go:2010

				})
				if err != nil {
					return nil, err
				}
			}
		}
	}
	return created, nil
}

func breakpoint(t *Term, ctx callContext, args string) error {
	_, err := setBreakpoint(t, ctx, false, args)
	return err
}

func tracepoint(t *Term, ctx callContext, args string) error {
	if ctx.Prefix == onPrefix {
		if args != "" {
			return errors.New("too many arguments to trace")
		}
		ctx.Breakpoint.Tracepoint = true
		return nil
	}
	_, err := setBreakpoint(t, ctx, true, args)
	return err
}

func getEditorName() (string, []string, error) {
	var editor string
	if editor = os.Getenv("DELVE_EDITOR"); editor == "" {
		if editor = os.Getenv("EDITOR"); editor == "" {
			return "", nil, errors.New("Neither DELVE_EDITOR or EDITOR is set")
		}
	}

	editorParts := strings.Fields(editor)
	editor = editorParts[0]

View on GitHub (pinned to a23773e6c3)

Solutions

1. Remove all arguments: use 'on <bp> trace' with nothing after 'trace'.
2. If you meant to create a new tracepoint at a location, drop the 'on' prefix and run 'trace <file:line>' instead.
3. If you wanted breakpoint variables printed on hit, use 'on <bp> print <expr>' rather than passing args to trace.

Example fix

// before
(dlv) on 1 trace main.myVar
// after
(dlv) on 1 trace

// in scripts driving the dlv terminal (batch/file mode)
func validateOnTrace(cmd string) error {
    if strings.HasPrefix(cmd, "on ") && strings.HasSuffix(cmd, "trace") &&
        len(strings.Fields(cmd)) != 3 {
        return fmt.Errorf("'on <bp> trace' takes no arguments: %q", cmd)
    }
    return nil
}

// Go: narrow a parsed command line before executing
func isBareTrace(ctxPrefix, args string) bool {
    return ctxPrefix == "on" && args == ""
}

if err := term.Cmd.Tracepoint(ctx, args); err != nil {
    if err.Error() == "too many arguments to trace" {
        // retry with bare command
        return term.Cmd.Tracepoint(ctx, "")
    }
    return err
}

When it happens

Trigger: Running 'on <breakpoint-id> trace <something>' with non-empty args, i.e. typing 'trace' with any extra argument while ctx.Prefix == onPrefix in the tracepoint handler (pkg/terminal/command.go tracepoint).

Common situations: Users habitually appending an expression or file:line to 'trace' the way they do with plain 'break', not realizing that inside an 'on' block trace takes no target.

Related errors

• filter not supported on breakpoint
• argument of deferred must be a number greater than 0 (use 's
• too many arguments to restart
• Invalid next count
• missing filename after -save flag

AI-assisted analysis of go-delve/delve@a23773e6c3 (2026-08-31). Data as JSON: /api/errors/ed52e81e479d87d6. Report an issue: GitHub.