databendlabs/databend · error

Zip type requires additional judgment and use…

Error message

Zip type requires additional judgment and use `decompress_all_zip`

What it means

The decompression codec factory in src/common/compress cannot build a generic streaming decoder for the Zip algorithm: ZIP archives hold multiple named entries and require per-entry handling, so CompressAlgorithm::Zip hits an unreachable!() panic in DecompressCodec::from. The message directs callers to use decompress_all_zip instead, which iterates and decompresses every entry of the archive.

Solutions

1. Route Zip inputs to decompress_all_zip before constructing a DecompressCodec
2. Check the CompressAlgorithm before calling from() and only build a codec for Gzip/Lzma/Xz/Zlib/Zstd
3. Change configuration to a supported streaming algorithm (e.g. gzip, zstd) when per-entry zip semantics are not needed
4. Replace the panic with a typed UnsupportedAlgorithm error for clearer diagnostics

Example fix

// before
let codec = DecompressCodec::from(algorithm); // panics when algorithm == Zip
// after
let data = match algorithm {
    CompressAlgorithm::Zip => decompress_all_zip(&raw)?,
    alg => DecompressCodec::from(alg).decode(&raw)?,
};

if algorithm == CompressAlgorithm::Zip {
    return decompress_all_zip(&input).map_err(|e| e.into());
}

fn is_streaming_codec(alg: CompressAlgorithm) -> bool {
    !matches!(alg, CompressAlgorithm::Zip)
}

match DecompressCodec::try_from(algorithm) {
    Ok(codec) => codec.decode(&data)?,
    Err(UnsupportedAlgorithm(Zip)) => decompress_all_zip(&data)?,
}

When it happens

Trigger: Constructing a DecompressCodec via From/`from` with CompressAlgorithm::Zip — e.g. a compression algorithm resolved from configuration or file metadata equals Zip and the generic decode path is taken instead of the dedicated zip path.

Common situations: A user configures compression = zip for a stage/stream decoder that only supports single-stream codecs; auto-detection of a .zip upload routes it to the generic decompressor; refactoring code that previously special-cased Zip removed the guard before calling from().

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Zip type requires additional judgment and use…
• internal error: entered unreachable code
• {}
• Temp table id used up
• Invalid temp table desc

AI-assisted analysis of databendlabs/databend@288d84d76e (2026-09-11). Data as JSON: /api/errors/5cf7b04aab52920f. Report an issue: GitHub.

Appendix: source

Thrown at src/common/compress/src/decode.rs:80

    /// Decoder for [`CompressAlgorithm::Zlib`]
    Zlib(ZlibDecoder),
    /// Decoder for [`CompressAlgorithm::Zstd`]
    Zstd(ZstdDecoder),
}

impl From<CompressAlgorithm> for DecompressCodec {
    fn from(v: CompressAlgorithm) -> Self {
        match v {
            CompressAlgorithm::Brotli => DecompressCodec::Brotli(Box::new(BrotliDecoder::new())),
            CompressAlgorithm::Bz2 => DecompressCodec::Bz2(BzDecoder::new()),
            CompressAlgorithm::Deflate => DecompressCodec::Deflate(DeflateDecoder::new()),
            CompressAlgorithm::Gzip => DecompressCodec::Gzip(GzipDecoder::new()),
            CompressAlgorithm::Lzma => DecompressCodec::Lzma(LzmaDecoder::new()),
            CompressAlgorithm::Xz => DecompressCodec::Xz(XzDecoder::new()),
            CompressAlgorithm::Zlib => DecompressCodec::Zlib(ZlibDecoder::new()),
            CompressAlgorithm::Zstd => DecompressCodec::Zstd(ZstdDecoder::new()),
            CompressAlgorithm::Zip => {
                unreachable!("Zip type requires additional judgment and use `decompress_all_zip`")
            }
        }
    }
}

impl Decode for DecompressCodec {
    fn reinit(&mut self) -> Result<()> {
        match self {
            DecompressCodec::Brotli(v) => v.reinit(),
            DecompressCodec::Bz2(v) => v.reinit(),
            DecompressCodec::Deflate(v) => v.reinit(),
            DecompressCodec::Gzip(v) => v.reinit(),
            DecompressCodec::Lzma(v) => v.reinit(),
            DecompressCodec::Xz(v) => v.reinit(),
            DecompressCodec::Zlib(v) => v.reinit(),
            DecompressCodec::Zstd(v) => v.reinit(),
        }
    }

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