System.InvalidOperationException in Deflate.Compress

[MerijnHendriks]

Describe the bug

When calling ZlibStream.Finish(); in deflate mode, System.InvalidOperationException is thrown.
This issue is not present in release 1.1.4.0 when using ZOutputStream.

Full stack trace:

System.InvalidOperationException: Operation is not valid due to the current state of the object.
  Stack Trace:
   at Elskom.Generic.Libs.Deflate.Compress(ZlibStream stream, ZlibFlushStrategy flush) in .\Haru.Compression\zlib.managed\Deflate.cs:line 416
   at Elskom.Generic.Libs.ZlibStream.Deflate(ZlibFlushStrategy flush) in .\Haru.Compression\zlib.managed\ZlibStream.cs:line 371
   at Elskom.Generic.Libs.ZlibStream.Finish() in .\Haru.Compression\zlib.managed\ZlibStream.cs:line 286
   at Haru.Compression.Zlib.Deflate(Byte[] data, ZlibCompression level) in .\Haru.Compression\Zlib.cs:line 17
   at Haru.Compression.Tests.ZlibTest.TestDeflate() in .\Haru.Compression.Tests\ZlibTest.cs:line 15

To Reproduce

I made a reproduction repo here.

If you do not wish to use the reproduction repo, you can use this instead:

using System.IO;
using System.Linq;
using Elskom.Generic.Libs;

class Program
{
    static readonly byte[] Inflated = new byte[]
    {
        // {"err":0,"errmsg":null,"data":{"utc_time":1692290139.1451}}
        0x7B, 0x22, 0x65, 0x72, 0x72, 0x22, 0x3A, 0x30, 0x2C, 0x22,
        0x65, 0x72, 0x72, 0x6D, 0x73, 0x67, 0x22, 0x3A, 0x6E, 0x75,
        0x6C, 0x6C, 0x2C, 0x22, 0x64, 0x61, 0x74, 0x61, 0x22, 0x3A,
        0x7B, 0x22, 0x75, 0x74, 0x63, 0x5F, 0x74, 0x69, 0x6D, 0x65,
        0x22, 0x3A, 0x31, 0x36, 0x39, 0x32, 0x32, 0x39, 0x30, 0x31,
        0x33, 0x39, 0x2E, 0x31, 0x34, 0x35, 0x31, 0x7D, 0x7D
    };

    static readonly byte[] Result = new byte[]
    {
        // [0x78, 0x9C]: [zlib, level 6]
        0x78, 0x9C, 0xAB, 0x56, 0x4A, 0x2D, 0x2A, 0x52, 0xB2, 0x32,
        0xD0, 0x01, 0xD1, 0xB9, 0xC5, 0xE9, 0x4A, 0x56, 0x79, 0xA5,
        0x39, 0x39, 0x3A, 0x4A, 0x29, 0x89, 0x25, 0x89, 0x4A, 0x56,
        0xD5, 0x4A, 0xA5, 0x25, 0xC9, 0xF1, 0x25, 0x99, 0xB9, 0xA9,
        0x4A, 0x56, 0x86, 0x66, 0x96, 0x46, 0x46, 0x96, 0x06, 0x86,
        0xC6, 0x96, 0x7A, 0x86, 0x26, 0xA6, 0x86, 0xB5, 0xB5, 0x00,
        0x36, 0x12, 0x11, 0xFC
    };

    static void Main()
    {
        using var msout = new MemoryStream();
        using var msin = new MemoryStream(Inflated);
        using var zs = new ZlibStream(msout, ZlibCompression.Level6, true);

        msin.CopyTo(zs);
        zs.Flush();
        zs.Finish();

        if (!msout.ToArray().SequenceEqual(Result))
        {
            throw new NotPackableException("Compression Failed.");
        }
    }
}

Expected behavior

ZlibStream to succeed deflating the data from the code above without issues.

Actual behavior

ZlibStream.Finish() throws System.InvalidOperationException.

Version used

• Branch main
• Commit d1fa75f.