What causes "Unknown GGUF array element type: ${elemType}" in ruvnet/ruflo?

Confirm the file parses with a reference GGUF reader (llama.cpp) to distinguish corruption from an unsupported type.

ruvnet/ruflo · error · Error

Unknown GGUF array element type: ${elemType}

Error message

Unknown GGUF array element type: ${elemType}

What it means

Thrown while reading a GGUF array value: the element type code (readGgufValue encountered valueType === ARRAY, then read the element type as elemType) is not one of the cases handled by readScalar, which returns undefined for unknown types. This indicates either an unknown/extended GGUF value type or buffer corruption causing a garbage type code.

Source

Thrown at v3/@claude-flow/cli/src/appliance/gguf-engine.ts:136

    case GgufValueType.BOOL:    return reader.readBool();
    case GgufValueType.STRING:  return reader.readString();
    case GgufValueType.UINT64:  return Number(reader.readU64());
    case GgufValueType.INT64:   return Number(reader.readI64());
    case GgufValueType.FLOAT64: return reader.readF64();
    default: return undefined;
  }
}

/** Read a single GGUF typed value (scalar or array) from the buffer. */
function readGgufValue(reader: BufferReader): unknown {
  const valueType = reader.readU32();
  if (valueType === GgufValueType.ARRAY) {
    const elemType = reader.readU32();
    const len = reader.readU64AsNumber();
    const arr: unknown[] = [];
    for (let i = 0; i < len; i++) {
      const v = readScalar(reader, elemType);
      if (v === undefined) throw new Error(`Unknown GGUF array element type: ${elemType}`);
      arr.push(v);
    }
    return arr;
  }
  const v = readScalar(reader, valueType);
  if (v === undefined) throw new Error(`Unknown GGUF value type: ${valueType}`);
  return v;
}

// ── GGUF Header Parsing ─────────────────────────────────────

/**
 * Parse the header and metadata from a GGUF file without loading tensors.
 * Reads only the first 256 KB of the file.
 */
export async function parseGgufHeader(path: string): Promise<GgufMetadata> {
  const fileInfo = await fsStat(path);
  const readSize = Math.min(fileInfo.size, 256 * 1024);

View on GitHub (pinned to 6b01dc5a68)

Solutions

Confirm the file parses with a reference GGUF reader (llama.cpp) to distinguish corruption from an unsupported type.
If the type is legitimate but unsupported, extend readScalar's switch to handle the new GgufValueType and add it to the enum.
Re-download the model to rule out transfer corruption.
For non-critical metadata, the parseGgufBuffer KV loop already try/catches per-entry, so partial metadata can still be usable if the unknown array is in a non-essential key.

Example fix

// before
// readScalar returns undefined for unsupported elemType

// after
function readScalar(reader: BufferReader, t: number): unknown {
  switch (t) {
    case GgufValueType.UINT8: return reader.readU8();
    // ... existing cases ...
    case NEW_TYPE_BOOL: return reader.readBool();
    default: return undefined;
  }
}

Defensive patterns

Strategy: fallback

Validate before calling

// No pre-check is possible for an unknown type; instead validate the file with a
// reference reader and, if a known-unsupported type is expected, extend readScalar.

Type guard

function isKnownValueType(t: number): boolean {
  return Object.values(GgufValueType).includes(t as GgufValueType);
}

Try / catch

try {
  return await parseGgufHeader(path);
} catch (e) {
  if (e instanceof Error && /Unknown GGUF array element type/.test(e.message)) {
    logger.warn({ path }, 'unsupported array type; some metadata unavailable');
  }
  throw e;
}

Prevention

Use GGUF files produced by current tooling.
Extend readScalar when adopting a newer GGUF spec.
Validate files with llama.cpp first.
Re-download to rule out corruption.

When it happens

Trigger: Parsing a GGUF whose metadata contains an array whose element type is outside the implemented GgufValueType set (e.g. a newer spec type the parser does not yet support), or a corrupted buffer where the element-type u32 is random.

Common situations: A GGUF produced by tooling that emits a value type this parser does not recognize (spec drift / newer GGUF revision); file corruption from an interrupted download; reading a non-GGUF file whose bytes happen to pass the magic check.

Related errors

AI-assisted analysis of ruvnet/ruflo@6b01dc5a68 (2026-08-12). Data as JSON: /api/errors/ac14fd2af83368ab. Report an issue: GitHub.