5 files changed, 223 insertions, 32 deletions
diff --git a/plumbing/transport/client/client.go b/plumbing/transport/client/client.go
index 770b7dc..095c51d 100644
--- a/plumbing/transport/client/client.go
+++ b/plumbing/transport/client/client.go
@@ -5,6 +5,7 @@ import (
 
 	"gopkg.in/src-d/go-git.v4/plumbing/transport"
 	"gopkg.in/src-d/go-git.v4/plumbing/transport/file"
+	"gopkg.in/src-d/go-git.v4/plumbing/transport/git"
 	"gopkg.in/src-d/go-git.v4/plumbing/transport/http"
 	"gopkg.in/src-d/go-git.v4/plumbing/transport/ssh"
 )
@@ -14,6 +15,7 @@ var Protocols = map[string]transport.Client{
 	"http":  http.DefaultClient,
 	"https": http.DefaultClient,
 	"ssh":   ssh.DefaultClient,
+	"git":   git.DefaultClient,
 	"file":  file.DefaultClient,
 }
 
diff --git a/plumbing/transport/git/common.go b/plumbing/transport/git/common.go
new file mode 100644
index 0000000..0fa7f5d
--- /dev/null
+++ b/plumbing/transport/git/common.go
@@ -0,0 +1,118 @@
+package git
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"strings"
+	"time"
+
+	"gopkg.in/src-d/go-git.v2/formats/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing/transport"
+	"gopkg.in/src-d/go-git.v4/plumbing/transport/internal/common"
+	"gopkg.in/src-d/go-git.v4/utils/ioutil"
+)
+
+var (
+	errAlreadyConnected = errors.New("tcp connection already connected")
+)
+
+// DefaultClient is the default git client.
+var DefaultClient = common.NewClient(&runner{})
+
+type runner struct{}
+
+// Command returns a new Command for the given cmd in the given Endpoint
+func (r *runner) Command(cmd string, ep transport.Endpoint) (common.Command, error) {
+	c := &command{command: cmd, endpoint: ep}
+	if err := c.connect(); err != nil {
+		return nil, err
+	}
+
+	return c, nil
+}
+
+type command struct {
+	conn      net.Conn
+	connected bool
+	command   string
+	endpoint  transport.Endpoint
+}
+
+// SetAuth cannot be called since git protocol doesn't support authentication
+func (c *command) SetAuth(auth transport.AuthMethod) error {
+	return transport.ErrInvalidAuthMethod
+}
+
+// Start executes the command sending the required message to the TCP connection
+func (c *command) Start() error {
+	cmd := endpointToCommand(c.command, c.endpoint)
+	line, err := pktline.EncodeFromString(cmd)
+	if err != nil {
+		return err
+	}
+
+	_, err = c.conn.Write([]byte(line))
+	return err
+}
+
+func (c *command) connect() error {
+	if c.connected {
+		return errAlreadyConnected
+	}
+
+	var err error
+	c.conn, err = net.DialTimeout("tcp", c.getHostWithPort(), time.Second)
+	if err != nil {
+		return err
+	}
+
+	c.connected = true
+	return nil
+}
+
+func (c *command) getHostWithPort() string {
+	host := c.endpoint.Host
+	if strings.Index(c.endpoint.Host, ":") == -1 {
+		host += ":9418"
+	}
+
+	return host
+}
+
+// StderrPipe git protocol doesn't have any dedicated error channel
+func (c *command) StderrPipe() (io.Reader, error) {
+	return nil, nil
+}
+
+// StdinPipe return the underlying connection as WriteCloser, wrapped to prevent
+// call to the Close function from the connection, a command execution in git
+// protocol can't be closed or killed
+func (c *command) StdinPipe() (io.WriteCloser, error) {
+	return ioutil.WriteNopCloser(c.conn), nil
+}
+
+// StdoutPipe return the underlying connection as Reader
+func (c *command) StdoutPipe() (io.Reader, error) {
+	return c.conn, nil
+}
+
+func endpointToCommand(cmd string, ep transport.Endpoint) string {
+	return fmt.Sprintf("%s %s%chost=%s%c", cmd, ep.Path, 0, ep.Host, 0)
+}
+
+// Wait no-op function, required by the interface
+func (c *command) Wait() error {
+	return nil
+}
+
+// Close closes the TCP connection and connection.
+func (c *command) Close() error {
+	if !c.connected {
+		return nil
+	}
+
+	c.connected = false
+	return c.conn.Close()
+}
diff --git a/plumbing/transport/git/common_test.go b/plumbing/transport/git/common_test.go
new file mode 100644
index 0000000..3f25ad9
--- /dev/null
+++ b/plumbing/transport/git/common_test.go
@@ -0,0 +1,9 @@
+package git
+
+import (
+	"testing"
+
+	. "gopkg.in/check.v1"
+)
+
+func Test(t *testing.T) { TestingT(t) }
diff --git a/plumbing/transport/git/fetch_pack_test.go b/plumbing/transport/git/fetch_pack_test.go
new file mode 100644
index 0000000..dc40240
--- /dev/null
+++ b/plumbing/transport/git/fetch_pack_test.go
@@ -0,0 +1,35 @@
+package git
+
+import (
+	"gopkg.in/src-d/go-git.v4/fixtures"
+	"gopkg.in/src-d/go-git.v4/plumbing/transport"
+	"gopkg.in/src-d/go-git.v4/plumbing/transport/test"
+
+	. "gopkg.in/check.v1"
+)
+
+type FetchPackSuite struct {
+	test.FetchPackSuite
+	fixtures.Suite
+}
+
+var _ = Suite(&FetchPackSuite{})
+
+func (s *FetchPackSuite) SetUpSuite(c *C) {
+	s.Suite.SetUpSuite(c)
+
+	s.FetchPackSuite.Client = DefaultClient
+
+	ep, err := transport.NewEndpoint("git://github.com/git-fixtures/basic.git")
+	c.Assert(err, IsNil)
+	s.FetchPackSuite.Endpoint = ep
+
+	ep, err = transport.NewEndpoint("git://github.com/git-fixtures/empty.git")
+	c.Assert(err, IsNil)
+	s.FetchPackSuite.EmptyEndpoint = ep
+
+	ep, err = transport.NewEndpoint("git://github.com/git-fixtures/non-existent.git")
+	c.Assert(err, IsNil)
+	s.FetchPackSuite.NonExistentEndpoint = ep
+
+}
diff --git a/plumbing/transport/internal/common/common.go b/plumbing/transport/internal/common/common.go
index f0e1691..f6d1249 100644
--- a/plumbing/transport/internal/common/common.go
+++ b/plumbing/transport/internal/common/common.go
@@ -132,22 +132,30 @@ func (c *client) newSession(s string, ep transport.Endpoint) (*session, error) {
 		return nil, err
 	}
 
+	return &session{
+		Stdin:         stdin,
+		Stdout:        stdout,
+		Command:       cmd,
+		errLines:      c.listenErrors(stderr),
+		isReceivePack: s == transport.ReceivePackServiceName,
+	}, nil
+}
+
+func (c *client) listenErrors(r io.Reader) chan string {
+	if r == nil {
+		return nil
+	}
+
 	errLines := make(chan string, errLinesBuffer)
 	go func() {
-		s := bufio.NewScanner(stderr)
+		s := bufio.NewScanner(r)
 		for s.Scan() {
 			line := string(s.Bytes())
 			errLines <- line
 		}
 	}()
 
-	return &session{
-		Stdin:         stdin,
-		Stdout:        stdout,
-		Command:       cmd,
-		errLines:      errLines,
-		isReceivePack: s == transport.ReceivePackServiceName,
-	}, nil
+	return errLines
 }
 
 // SetAuth delegates to the command's SetAuth.
@@ -163,38 +171,52 @@ func (s *session) AdvertisedReferences() (*packp.AdvRefs, error) {
 
 	ar := packp.NewAdvRefs()
 	if err := ar.Decode(s.Stdout); err != nil {
-		// If repository is not found, we get empty stdout and server
-		// writes an error to stderr.
-		if err == packp.ErrEmptyInput {
-			if err := s.checkNotFoundError(); err != nil {
-				return nil, err
-			}
-
-			return nil, io.ErrUnexpectedEOF
+		if err := s.handleAdvRefDecodeError(err); err != nil {
+			return nil, err
 		}
+	}
 
-		// For empty (but existing) repositories, we get empty
-		// advertised-references message. But valid. That is, it
-		// includes at least a flush.
-		if err == packp.ErrEmptyAdvRefs {
-			// Empty repositories are valid for git-receive-pack.
-			if s.isReceivePack {
-				return ar, nil
-			}
+	transport.FilterUnsupportedCapabilities(ar.Capabilities)
+	s.advRefs = ar
+	return ar, nil
+}
+
+func (s *session) handleAdvRefDecodeError(err error) error {
+	// If repository is not found, we get empty stdout and server writes an
+	// error to stderr.
+	if err == packp.ErrEmptyInput {
+		if err := s.checkNotFoundError(); err != nil {
+			return err
+		}
+
+		return io.ErrUnexpectedEOF
+	}
 
-			if err := s.finish(); err != nil {
-				return nil, err
-			}
+	// For empty (but existing) repositories, we get empty advertised-references
+	// message. But valid. That is, it includes at least a flush.
+	if err == packp.ErrEmptyAdvRefs {
+		// Empty repositories are valid for git-receive-pack.
+		if s.isReceivePack {
+			return nil
+		}
 
-			return nil, transport.ErrEmptyRemoteRepository
+		if err := s.finish(); err != nil {
+			return err
 		}
 
-		return nil, err
+		return transport.ErrEmptyRemoteRepository
 	}
 
-	transport.FilterUnsupportedCapabilities(ar.Capabilities)
-	s.advRefs = ar
-	return ar, nil
+	// Some server sends the errors as normal content (git protocol), so when
+	// we try to decode it fails, we need to check the content of it, to detect
+	// not found errors
+	if uerr, ok := err.(*packp.ErrUnexpectedData); ok {
+		if isRepoNotFoundError(string(uerr.Data)) {
+			return transport.ErrRepositoryNotFound
+		}
+	}
+
+	return err
 }
 
 // FetchPack performs a request to the server to fetch a packfile. A reader is
@@ -317,6 +339,7 @@ var (
 	githubRepoNotFoundErr    = "ERROR: Repository not found."
 	bitbucketRepoNotFoundErr = "conq: repository does not exist."
 	localRepoNotFoundErr     = "does not appear to be a git repository"
+	gitProtocolNotFoundErr   = "ERR \n  Repository not found."
 )
 
 func isRepoNotFoundError(s string) bool {
@@ -332,6 +355,10 @@ func isRepoNotFoundError(s string) bool {
 		return true
 	}
 
+	if strings.HasPrefix(s, gitProtocolNotFoundErr) {
+		return true
+	}
+
 	return false
 }