Decompressing gzip: `invalid header`

[rgmz]

I've encountered what I believe is a valid GZIP file. However, attempting to read the contents results in the error gzip: invalid header. It's not clear to me what the error is, as the file is successfully decompressed with both gunzip and Java (see examples below).

Steps to Reproduce

1. Download https://github.com/akuang/self-driving-car-sim/blob/4b1f739ebda9ed4920fe895ee3677bd4ccb79218/Assets/Standard%20Assets/Environment/SpeedTree/Conifer/Conifer_Desktop.spm

2. Run the following reproducer code.

   import (
       "io"
       "os"
       "testing"
   
       "github.com/klauspost/compress/gzip"
       "github.com/stretchr/testify/require"
   )
   
   func TestGzip(t *testing.T) {
       f, err := os.Open("/tmp/Conifer_Desktop.spm")
       require.NoError(t, err)
       defer f.Close()
   
       rc, err := gzip.NewReader(f)
       require.NoError(t, err)
       defer rc.Close()
   
       _, err = io.ReadAll(rc)
       require.NoError(t, err)
   }

3. Observe the error invalid header

   $ go test gzip_test.go 
   --- FAIL: TestGzip (0.01s)
       main_test.go:22:
                   Error Trace:    /tmp/repro/gzip_test.go:22
                   Error:          Received unexpected error:
                                   gzip: invalid header
                   Test:           TestGzip
   FAIL
   FAIL    command-line-arguments  0.017s
   FAIL

Working Examples

gunzip

There is a warning about trailing garbage which may be relevant.

$ file -i Conifer_Desktop.spm
Conifer_Desktop.spm: application/gzip; charset=binary
$ gunzip -f Conifer_Desktop.spm -S .spm

gzip: Conifer_Desktop.spm: decompression OK, trailing garbage ignored

Java Code

import java.io.*;
import java.util.zip.GZIPInputStream;

public class Main {

    public static void main(String[] args) {
        var in = "C:\\Users\\Me\\Downloads\\Conifer_Desktop.spm";
        var out = STR."\{in}.out";

        decompressGzip(in, out);
    }

    public static void decompressGzip(String inputFile, String outputFile) {

        try (var gis = new GZIPInputStream(new FileInputStream(inputFile));
             var fos = new FileOutputStream(outputFile)) {

            // copy GZIPInputStream to FileOutputStream
            byte[] buffer = new byte[1024];
            int len;
            while ((len = gis.read(buffer)) > 0) {
                fos.write(buffer, 0, len);
            }
        } catch (Throwable e) {
            e.printStackTrace();
        }
    }
}

[klauspost]

See https://pkg.go.dev/github.com/klauspost/compress/gzip#Reader.Multistream

Add rc.Multistream(false)