by emilliken:

Saw this panic in some legit code, but the following will trigger it:

package main

import (
        "bytes"
        "compress/zlib"
        "fmt"
        "io"
        "os"
)

func main() {
        f, err := os.Open("/dev/urandom")
        if err != nil {
                fmt.Println(err)
                os.Exit(1)
        }
        buf := make([]byte, 1024)
        buf3 := make([]byte, 4096)
        for {
                _, err := io.ReadFull(f, buf)
                if err != nil {
                        fmt.Println(err)
                        os.Exit(1)
                }
                buf2 := bytes.NewBuffer(buf)
                for i := 0; i < buf2.Len(); i++ {
                        sl := bytes.NewBuffer(buf2.Bytes()[i:])
                        zz, err := zlib.NewReader(sl)
                        if err != nil {
                                continue
                        }
                        zz.Read(buf3)
                }
        }
}

What is the expected output?
nothing

What do you see instead?
panic: runtime error: index out of range

goroutine 1 [running]:
compress/flate.(*decompressor).readHuffman(0xf84005b000, 0x0, 0x0, 0x7f139bb20d90)
        /home/e/go/src/pkg/compress/flate/inflate.go:343 +0x3cf
compress/flate.(*decompressor).nextBlock(0xf84005b000, 0x48d2f0)
        /home/e/go/src/pkg/compress/flate/inflate.go:262 +0x1ab
compress/flate.(*decompressor).Read(0xf84005b000, 0xf84005a000, 0x100000001000,
0xf8400d24b0, 0xf84002c930, ...)
        /home/e/go/src/pkg/compress/flate/inflate.go:284 +0x136
compress/zlib.(*reader).Read(0xf8400d24b0, 0xf84005a000, 0x100000001000, 0xf8400d24b0,
0x0, ...)
        /home/e/go/src/pkg/compress/zlib/reader.go:103 +0x101


Which compiler are you using (5g, 6g, 8g, gccgo)?
8g

Which operating system are you using?
freebsd 8.1

Which version are you using?  (run 'go version')
go 1.0.2

Please provide any additional information below.