by travis.bischel:

gzip Reset should work on an uninitialized gzip Reader.

This goes along with this discussion:
https://groups.google.com/forum/#!topic/golang-dev/e7E6viMqwN0

What does 'go version' print?
go version devel +f8b50ad4cac4 Mon Apr 21 17:00:27 2014 -0700 + linux/amd64

What steps reproduce the problem?
http://play.golang.org/p/9F1Tn1pZ9O

What happened?
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x28 pc=0x429fa9]

goroutine 16 [running]:
runtime.panic(0x4dd680, 0x593853)
    /usr/local/go/src/pkg/runtime/panic.c:279 +0xf5
compress/gzip.(*Reader).Reset(0xc2081b2000, 0x7f92548af4e0, 0xc20802c070, 0x0, 0x0)
    /home/twmb/fastly/shared/dev/go/go1.3beta1/src/pkg/compress/gzip/gunzip.go:97 +0x69
main.main()
    /home/twmb/demonstrate.go:22 +0x1bd

goroutine 17 [runnable]:
runtime.MHeap_Scavenger()
    /usr/local/go/src/pkg/runtime/mheap.c:507
runtime.goexit()
    /usr/local/go/src/pkg/runtime/proc.c:1430

goroutine 18 [runnable]:
bgsweep()
    /usr/local/go/src/pkg/runtime/mgc0.c:1960
runtime.goexit()
    /usr/local/go/src/pkg/runtime/proc.c:1430

goroutine 19 [runnable]:
runfinq()
    /usr/local/go/src/pkg/runtime/mgc0.c:2586
runtime.goexit()
    /usr/local/go/src/pkg/runtime/proc.c:1430
exit status 2

What should have happened instead?
hello should be printed.

Please provide any additional information below.
Line 97 of http://tip.golang.org/src/pkg/compress/gzip/gunzip.go, digest is nil because
it is an uninitialized pointer. This could be fixed by having an

if digest == nil {
        z.digest = crc32.NewIEEE()
}

before the z.digest.Reset() call.

NewReader must be called first to initialize digest. If I want to gunzip in a for loop,
I currently must seed the unzipr with valid data before calling Reset on every
iteration. This is not a critical issue, but it would need to go out before 1.3 is
released otherwise doing this issue would break the same API compatibility discussed in
the golang-dev thread. Or, this issue could be shot down.