FuelLabs/fuels-ts · error · FuelError

DECODE_ERROR

DECODE_ERROR

Error message

Invalid enum data size.

What it means

Thrown by EnumCoder.decode at the first length guard: this.#shouldValidateLength is true and data.length < this.encodedLength. encodedLength is the case-index (8) plus the minimum value size. Message: "Invalid enum data size.". Note length validation is skipped for Option/nested-option enums (#shouldValidateLength is false), so this only fires for regular enums.

Source

Thrown at packages/abi-coder/src/encoding/coders/EnumCoder.ts:93

        .join(', ');
      throw new FuelError(
        ErrorCode.INVALID_DECODE_VALUE,
        `Invalid case '${caseKey}'. Valid cases: ${validCases}.`
      );
    }

    const encodedValue = valueCoder.encode(value[caseKey]);

    return new Uint8Array([...this.#caseIndexCoder.encode(caseIndex), ...encodedValue]);
  }

  #decodeNativeEnum(caseKey: string, newOffset: number): [DecodedValueOf<TCoders>, number] {
    return [caseKey as unknown as DecodedValueOf<TCoders>, newOffset];
  }

  decode(data: Uint8Array, offset: number): [DecodedValueOf<TCoders>, number] {
    if (this.#shouldValidateLength && data.length < this.encodedLength) {
      throw new FuelError(ErrorCode.DECODE_ERROR, `Invalid enum data size.`);
    }

    const caseBytes = new BigNumberCoder('u64').decode(data, offset)[0];
    const caseIndex = toNumber(caseBytes);
    const caseKey = Object.keys(this.coders)[caseIndex];
    if (!caseKey) {
      throw new FuelError(
        ErrorCode.INVALID_DECODE_VALUE,
        `Invalid caseIndex "${caseIndex}". Valid cases: ${Object.keys(this.coders)}.`
      );
    }
    const valueCoder = this.coders[caseKey];
    const offsetAndCase = offset + this.#caseIndexCoder.encodedLength;

    if (this.#shouldValidateLength && data.length < offsetAndCase + valueCoder.encodedLength) {
      throw new FuelError(ErrorCode.DECODE_ERROR, `Invalid enum data size.`);
    }

View on GitHub (pinned to b3f37c91ac)

Solutions

1. Confirm data.length >= enumCoder.encodedLength before decode.
2. Verify you are using the correct enum coder for the data.
3. Let the high-level decoder manage offsets.

if (enumCoder['#shouldValidateLength'] !== false && data.length < enumCoder.encodedLength) {
  throw new Error('buffer too short for enum')
}
enumCoder.decode(data, offset)

const canDecodeEnum = (data: Uint8Array, len: number) => data.length >= len

try { enumCoder.decode(data, offset) }
catch (e) { if ((e as FuelError).code === ErrorCode.DECODE_ERROR) { /* truncated payload / wrong coder */ } throw e }

When it happens

Trigger: Decoding a non-Option enum from a buffer shorter than the enum's encoded length (case index + value). Common with truncated return data or wrong coder.

Common situations: Truncated receipt/return data; decoding at a wrong offset; using a regular-enum coder on data that is actually an Option; provider truncation.

Related errors

• DECODE_ERROR
• DECODE_ERROR
• DECODE_ERROR
• DECODE_ERROR
• DECODE_ERROR

AI-assisted analysis of FuelLabs/fuels-ts@b3f37c91ac (2026-08-12). Data as JSON: /api/errors/1e4734c6e5d0598f. Report an issue: GitHub.