abpframework/abp · warning · ArgumentException

Should specify an option name after '--' prefix!

Error message

Should specify an option name after '--' prefix!

What it means

Thrown by CommandLineArgumentParser.ParseOptionName when an argument equals exactly '--' (length <= 2 after the prefix check). The parser expects a name token immediately after the '--' prefix; a bare '--' with no following characters is not a valid option name. This is part of the ABP CLI's internal argument tokenizer.

Source

Thrown at framework/src/Volo.Abp.Cli.Core/Volo/Abp/Cli/Args/CommandLineArgumentParser.cs:91

    }

    public CommandLineArgs Parse(string lineText)
    {
        return Parse(GetArgsArrayFromLine(lineText));
    }

    private static bool IsOptionName(string argument)
    {
        return argument.StartsWith("-") || argument.StartsWith("--");
    }

    private static string ParseOptionName(string argument)
    {
        if (argument.StartsWith("--"))
        {
            if (argument.Length <= 2)
            {
                throw new ArgumentException("Should specify an option name after '--' prefix!");
            }

            return argument.RemovePreFix("--");
        }

        if (argument.StartsWith("-"))
        {
            if (argument.Length <= 1)
            {
                throw new ArgumentException("Should specify an option name after '-' prefix!");
            }

            return argument.RemovePreFix("-");
        }

        throw new ArgumentException("Option names should start with '-' or '--'.");
    }

View on GitHub (pinned to 7ed43b1931)

Solutions

1. Remove the bare '--' from the command line; every option must have a name after the prefix.
2. Inspect the exact arguments passed (print argv) to find which token is the empty '--'.
3. If generating commands programmatically, filter out tokens that are exactly '--' or '-' before invoking the parser.
4. Use a single '-' prefix or fully named options ('--version') and ensure no token is left truncated.

Example fix

# before
abp new MyProject --
# after (remove the bare double-dash)
abp new MyProject --version

// Sanitize argument tokens before invoking the CLI parser.
var sanitized = args.Where(a => a != "--").ToArray();
if (sanitized.Length != args.Length)
{
    Console.Error.WriteLine("Removed empty '--' token from arguments.");
}
var parsed = parser.Parse(sanitized);

public static bool IsValidOptionToken(string arg) =>
    !arg.StartsWith("--") || arg.Length > 2;

try
{
    var cmd = parser.Parse(args);
}
catch (ArgumentException ex) when (ex.Message.Contains("'--' prefix", StringComparison.Ordinal))
{
    Console.Error.WriteLine($"Invalid CLI input: a bare '--' is not allowed. Args: {string.Join(' ', args)}");
    return ExitCodes.InvalidArguments;
}

When it happens

Trigger: The CLI is invoked with a standalone '--' token, e.g., 'abp new MyProj --' or a script passes an empty '--'. GetArgsArrayFromLine yields '--' as a token and the options loop feeds it to ParseOptionName.

Common situations: User typo at the terminal; a wrapper script or CI step that concatenates flags and emits an empty '--'; copy-pasting a command where a flag value was deleted but the '--' left behind; shell glob/quoting producing an empty double-dash token.

Related errors

• Should specify an option name after '-' prefix!
• Option names should start with '-' or '--'.
• There is no template found with given name: {name}
• "public class" declaration not found!
• ERROR: Remote server returns '{response.StatusCode}'

AI-assisted analysis of abpframework/abp@7ed43b1931 (2026-08-13). Data as JSON: /api/errors/d0fc8d1028ba4a75. Report an issue: GitHub.