Duplicating file suffix causes panic: "entered unreachable code"

[k4yt3x]

Version

0.4.1

Description

I came a cross this panic when I was trying to decompress a ZIP file with two .zip suffixes. It's easy to reproduce:

Current Behavior

Decompressing a file like test.zip.zip with two suffixes causes the program to panic.

Expected Behavior

The program should decompress the file normally and guess the file's type using the last suffix.

Additional Information

No response

[vrmiguel]

Hey @k4yt3x, thanks a lot for the report!

[vrmiguel]

Panic happens here:

ouch/src/commands/decompress.rs

Line 89 in a3e1eb4

Tar | Zip => unreachable!(),

There's not zip::read::Decoder or something that would impl Read from the zip crate, as far as I know

One thing we could do is do this instead

    let chain_reader_decoder = |format: &CompressionFormat, decoder: Box<dyn Read>| -> crate::Result<Box<dyn Read>> {
        let decoder: Box<dyn Read> = match format {
            Gzip => Box::new(flate2::read::GzDecoder::new(decoder)),
            Bzip => Box::new(bzip2::read::BzDecoder::new(decoder)),
            Lz4 => Box::new(lzzzz::lz4f::ReadDecompressor::new(decoder)?),
            Lzma => Box::new(xz2::read::XzDecoder::new(decoder)),
            Snappy => Box::new(snap::read::FrameDecoder::new(decoder)),
            Zstd => Box::new(zstd::stream::Decoder::new(decoder)?),
            Tar | Zip => decoder, // Return the decoder itself
        };
        Ok(decoder)
    };

Doing this, if passed in something like file.tar.zip or file.zip.zip, we'd unpack the outer compression, save file.tar | file.zip and finish

The user could then re-run ouch on the resulting file

@marcospb19 @figsoda I opened the PR for the change above, am open to suggestions