plumbing/transport: add common tests and fixes. (#136)

* plumbing/transport: add common tests and fixes.

* add common test suite for different transport implementations.
* fix different behaviour on error handling for ssh and http.
  fixes issue #123.
* support detecting unexisting repositories with SSH + GitHub/Bitbucket
  (apparently, there is no standard for all SSH servers).
* remove ssh.NewClient (only DefaultClient makes sense at the moment).
* make ssh.Client and http.Client private.
* utils/ioutil: utilities to work with io interfaces.

* * transport: test actual objects fetched, not just packfile size.

* * fix doc typo.

* * improve UploadPackRequest.IsEmpty

2 files changed, 38 insertions, 0 deletions

diff --git a/plumbing/format/packp/advrefs/decoder.go b/plumbing/format/packp/advrefs/decoder.go
index b654882..c50eeef 100644
--- a/plumbing/format/packp/advrefs/decoder.go
+++ b/plumbing/format/packp/advrefs/decoder.go
@@ -86,6 +86,12 @@ func decodePrefix(d *Decoder) decoderStateFn {
 		return nil
 	}
 
+	// If the repository is empty, we receive a flush here (SSH).
+	if isFlush(d.line) {
+		d.err = ErrEmpty
+		return nil
+	}
+
 	if isPrefix(d.line) {
 		tmp := make([]byte, len(d.line))
 		copy(tmp, d.line)
@@ -117,6 +123,12 @@ func isFlush(payload []byte) bool {
 // list-of-refs is comming, and the hash will be followed by the first
 // advertised ref.
 func decodeFirstHash(p *Decoder) decoderStateFn {
+	// If the repository is empty, we receive a flush here (HTTP).
+	if isFlush(p.line) {
+		p.err = ErrEmpty
+		return nil
+	}
+
 	if len(p.line) < hashSize {
 		p.error("cannot read hash, pkt-line too short")
 		return nil
diff --git a/plumbing/format/packp/advrefs/decoder_test.go b/plumbing/format/packp/advrefs/decoder_test.go
index 03867d3..bacf79a 100644
--- a/plumbing/format/packp/advrefs/decoder_test.go
+++ b/plumbing/format/packp/advrefs/decoder_test.go
@@ -26,6 +26,32 @@ func (s *SuiteDecoder) TestEmpty(c *C) {
 	c.Assert(err, Equals, advrefs.ErrEmpty)
 }
 
+func (s *SuiteDecoder) TestEmptyFlush(c *C) {
+	ar := advrefs.New()
+	var buf bytes.Buffer
+	e := pktline.NewEncoder(&buf)
+	e.Flush()
+
+	d := advrefs.NewDecoder(&buf)
+
+	err := d.Decode(ar)
+	c.Assert(err, Equals, advrefs.ErrEmpty)
+}
+
+func (s *SuiteDecoder) TestEmptyPrefixFlush(c *C) {
+	ar := advrefs.New()
+	var buf bytes.Buffer
+	e := pktline.NewEncoder(&buf)
+	e.EncodeString("# service=git-upload-pack")
+	e.Flush()
+	e.Flush()
+
+	d := advrefs.NewDecoder(&buf)
+
+	err := d.Decode(ar)
+	c.Assert(err, Equals, advrefs.ErrEmpty)
+}
+
 func (s *SuiteDecoder) TestShortForHash(c *C) {
 	payloads := []string{
 		"6ecf0ef2c2dffb796",