can1357/oh-my-pi · error · ArchiveError

Unsupported XZ filter ID 0x${filter.id.toString(16)}

Error message

Unsupported XZ filter ID 0x${filter.id.toString(16)}

What it means

The XZ block decoder only implements a fixed set of optional filters: Delta (3) and the BCJ family (x86=4, PowerPC=5, IA-64=6, ARM=7/8, SPARC=9, ARM64=10, RISC-V=11). It throws when a block declares a filter ID outside the implemented switch — the stream may be valid XZ but uses a filter this decoder does not support.

Source

Thrown at packages/utils/src/ar/codecs/xz.ts:407

			ia64Decode(bytes, startOffset);
			break;
		case 7:
			armDecode(bytes, startOffset);
			break;
		case 8:
			armThumbDecode(bytes, startOffset);
			break;
		case 9:
			sparcDecode(bytes, startOffset);
			break;
		case 10:
			arm64Decode(bytes, startOffset);
			break;
		case 11:
			riscvDecode(bytes, startOffset);
			break;
		default:
			throw new ArchiveError(`Unsupported XZ filter ID 0x${filter.id.toString(16)}`);
	}
}

function verifyCheck(checkId: number, output: Uint8Array, expected: Uint8Array): void {
	if (checkId === 0) return;
	if (checkId === 1) {
		if (read32LE(expected, 0) !== crc32(output)) throw new ArchiveError("Invalid XZ stream: block CRC32 mismatch");
		return;
	}
	if (checkId === 4) {
		const actual = crc64(output);
		let stored = 0n;
		for (let index = 0; index < 8; index++) stored |= BigInt(expected[index]!) << BigInt(index * 8);
		if (actual !== stored) throw new ArchiveError("Invalid XZ stream: block CRC64 mismatch");
		return;
	}
	const actual = new Uint8Array(new Bun.CryptoHasher("sha256").update(output).digest());
	if (!equalBytes(actual, expected)) throw new ArchiveError("Invalid XZ stream: block SHA-256 mismatch");

View on GitHub (pinned to 9690622007)

Solutions

1. Re-compress the archive without optional BCJ/Delta filters: `xz --format=xz -z` without --x86 etc., or plain LZMA2 only
2. Decode the file externally with the reference xz binary and pass uncompressed data to the library
3. Check if a newer version of this library/package adds support for the filter ID and upgrade
4. If the input is untrusted, treat unsupported-filter as an expected rejection and inform the user

Example fix

// before: file compressed with an unsupported BCJ filter chain
// $ xz --sparc --x86 file.bin
// after: compress with default settings so blocks use LZMA2 only
// $ xz -z file.bin

null

const SUPPORTED_FILTER_IDS = new Set([3, 4, 5, 6, 8, 10, 11]);
function filtersSupported(ids: number[]): boolean {
  return ids.every((id) => SUPPORTED_FILTER_IDS.has(id));
}

try {
  return await decodeXz(bytes);
} catch (err) {
  if (err instanceof ArchiveError && err.message.startsWith('Unsupported XZ filter ID')) {
    // fall back to an external, fully-featured xz implementation
    const out = await $`xz -dc archive.xz`.quiet().nothrow();
    if (out.exitCode === 0) return new Uint8Array(await out.arrayBuffer());
  }
  throw err;
}

When it happens

Trigger: Decoding an XZ stream whose block filter list contains an ID not handled by the switch (e.g. a hypothetical future filter, or an ID misread from a corrupt header).

Common situations: Files compressed with encoder configurations this pure-TS decoder doesn't implement (exotic filter chains); streams from newer xz versions introducing filters after this code was written; corrupted block headers yielding garbage filter IDs.

Related errors

• Unsupported XZ terminal filter ID 0x${last.id.toString(16)}
• Unsupported RAR5 filter type ${type}
• ARJ member '${memberPath}' uses unsupported compression meth
• Encrypted ARJ archives are unsupported
• Multi-volume ARJ archives are unsupported

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/860e7d728c47371a. Report an issue: GitHub.