apache/cassandra · error · InvalidRequestException

ALTER [ROLE|USER] can't be empty

Error message

ALTER [ROLE|USER] can't be empty

What it means

AlterRoleStatement.validate rejects an ALTER ROLE/USER statement that specifies nothing to change: no role options, no DC permissions change, and no CIDR permissions change. Such a statement is a no-op and is treated as invalid input.

Source

Thrown at src/java/org/apache/cassandra/cql3/statements/AlterRoleStatement.java:76

        this(name, opts, null, null, false);
    }

    public AlterRoleStatement(RoleName name, RoleOptions opts, DCPermissions dcPermissions,
                              CIDRPermissions cidrPermissions, boolean ifExists)
    {
        this.role = RoleResource.role(name.getName());
        this.opts = opts;
        this.dcPermissions = dcPermissions;
        this.cidrPermissions = cidrPermissions;
        this.ifExists = ifExists;
    }

    public void validate(ClientState state) throws RequestValidationException
    {
        opts.validate();

        if (opts.isEmpty() && dcPermissions == null && cidrPermissions == null)
            throw new InvalidRequestException("ALTER [ROLE|USER] can't be empty");

        if (dcPermissions != null)
        {
            dcPermissions.validate();
        }

        if (cidrPermissions != null)
        {
            // Ensure input CIDR group names are valid, i.e, existing in CIDR groups mapping table
            cidrPermissions.validate();
        }

        // validate login here before authorize, to avoid leaking user existence to anonymous users.
        state.ensureNotAnonymous();
        if (!DatabaseDescriptor.getRoleManager().isExistingRole(role))
        {
            checkTrue(ifExists, "Role %s doesn't exist", role.getRoleName());
        }

View on GitHub (pinned to 88fd0f6a0e)

Solutions

1. Add at least one option, e.g. WITH PASSWORD = '...', WITH LOGIN = true, or SUPERUSER = false
2. Add a DC ACCESS or CIDR permissions clause if that is the intended change
3. Remove the statement entirely if no change was intended

Example fix

// before
ALTER ROLE app_role;
// after
ALTER ROLE app_role WITH LOGIN = true;

// ensure the ALTER has at least one change before executing
boolean hasChange = !options.isEmpty() || dcPermissions != null || cidrPermissions != null;
if (!hasChange) throw new IllegalArgumentException("ALTER ROLE needs at least one option, DC permission, or CIDR permission");

try { session.execute(alterRoleCql); } catch (InvalidRequestException e) { if (e.getMessage().contains("can't be empty")) { /* skip no-op or add options */ } else throw e; }

When it happens

Trigger: ALTER ROLE some_role; or ALTER USER alice; with no WITH option clause and no dcPermissions/cidrPermissions clause, after opts.validate() passes.

Common situations: Programmatically generated ALTER statements where all option fields were empty; partial template rendering that dropped the options; fat-fingered statements with only the role name.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Multiple definition for property '%s'
• You aren't allowed to alter %s
• Role name can't be an empty string
• %s already exists
• Only superusers can drop a role with superuser status

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/0e16efff68491a42. Report an issue: GitHub.