gchq/CyberChef · error · OperationError

A minimum of one reflector must be supplied

Error message

A minimum of one reflector must be supplied

What it means

Thrown by MultipleBombe.run when the reflectors list ends up empty after splitting args[3] on newlines. At least one reflector is required because the Bombe loops over reflector choices. In practice this branch is hard to reach because even an empty string splits to [''] and the loop constructs one Reflector.

Source

Thrown at src/core/operations/MultipleBombe.mjs:214

        }
        if (rotors.length < 3) {
            throw new OperationError("A minimum of three rotors must be supplied");
        }
        if (fourthRotorsStr !== "") {
            for (let rstr of fourthRotorsStr.split("\n")) {
                rstr = this.validateRotor(rstr);
                fourthRotors.push(rstr);
            }
        }
        if (fourthRotors.length === 0) {
            fourthRotors.push("");
        }
        for (const rstr of reflectorsStr.split("\n")) {
            const reflector = new Reflector(rstr);
            reflectors.push(reflector);
        }
        if (reflectors.length === 0) {
            throw new OperationError("A minimum of one reflector must be supplied");
        }
        if (crib.length === 0) {
            throw new OperationError("Crib cannot be empty");
        }
        if (offset < 0) {
            throw new OperationError("Offset cannot be negative");
        }
        // For symmetry with the Enigma op, for the input we'll just remove all invalid characters
        input = input.replace(/[^A-Za-z]/g, "").toUpperCase();
        crib = crib.replace(/[^A-Za-z]/g, "").toUpperCase();
        const ciphertext = input.slice(offset);
        let update;
        if (isWorkerEnvironment()) {
            update = this.updateStatus;
        } else {
            update = undefined;
        }
        let bombe = undefined;

View on GitHub (pinned to 4290ea7539)

Solutions

1. Provide at least one reflector wiring string (e.g. the standard B reflector 'YRUHQSLDPXNGOKMIEBFZCWVJAT').
2. Ensure the reflectors argument is a string, never null or undefined.
3. Restore default reflector values if the field was cleared.

Example fix

// before
chef.bake("Multiple Bombe", [..., reflectors="", ...]);
// after
chef.bake("Multiple Bombe", [..., reflectors="YRUHQSLDPXNGOKMIEBFZCWVJAT", ...]);

const reflectorsStr = args[3];
if (typeof reflectorsStr !== "string" || reflectorsStr.split("\n").length === 0) {
  // supply a reflector string
}

const hasReflector = (s) => typeof s === "string" && s.length > 0;

try { chef.bake("Multiple Bombe", args); }
catch (e) { if (e.message === "A minimum of one reflector must be supplied") addReflector(); else throw e; }

When it happens

Trigger: run(input, args) where reflectors.length === 0 after the split/construct loop. Realistically reachable only if args[3] is something that produces no iterations (e.g. the reflector string is manipulated to yield an array that the for..of skips), since ''.split('\n') returns [''] and the loop runs once.

Common situations: Recipe where the reflectors field was set to null/undefined rather than a string; programmatic invocation passing a non-string reflectors argument; edge cases where a Reflector constructor throws and is caught upstream leaving the array empty (not the case in this code).

Related errors

• Rotor wiring must be 26 unique uppercase letters
• A minimum of three rotors must be supplied
• Crib cannot be empty
• Offset cannot be negative
• ${name} connects ${pair[1]} more than once

AI-assisted analysis of gchq/CyberChef@4290ea7539 (2026-08-13). Data as JSON: /api/errors/2dfd3e9a4ca23998. Report an issue: GitHub.