remote: add Push (#178)

* remote: add Push.

* add Push method to Remote.
* add method Push to Repository.
* examples: add push example.

* requested changes

* add tests, fixes

4 files changed, 80 insertions, 25 deletions

diff --git a/plumbing/protocol/packp/report_status.go b/plumbing/protocol/packp/report_status.go
index ead4bb6..29c1a4c 100644
--- a/plumbing/protocol/packp/report_status.go
+++ b/plumbing/protocol/packp/report_status.go
@@ -26,9 +26,19 @@ func NewReportStatus() *ReportStatus {
 	return &ReportStatus{}
 }
 
-// Ok returns true if the report status reported no error.
-func (s *ReportStatus) Ok() bool {
-	return s.UnpackStatus == ok
+// Error returns the first error if any.
+func (s *ReportStatus) Error() error {
+	if s.UnpackStatus != ok {
+		return fmt.Errorf("unpack error: %s", s.UnpackStatus)
+	}
+
+	for _, s := range s.CommandStatuses {
+		if err := s.Error(); err != nil {
+			return err
+		}
+	}
+
+	return nil
 }
 
 // Encode writes the report status to a writer.
@@ -135,14 +145,19 @@ type CommandStatus struct {
 	Status        string
 }
 
-// Ok returns true if the command status reported no error.
-func (s *CommandStatus) Ok() bool {
-	return s.Status == ok
+// Error returns the error, if any.
+func (s *CommandStatus) Error() error {
+	if s.Status == ok {
+		return nil
+	}
+
+	return fmt.Errorf("command error on %s: %s",
+		s.ReferenceName.String(), s.Status)
 }
 
 func (s *CommandStatus) encode(w io.Writer) error {
 	e := pktline.NewEncoder(w)
-	if s.Ok() {
+	if s.Error() == nil {
 		return e.Encodef("ok %s\n", s.ReferenceName.String())
 	}
 
diff --git a/plumbing/protocol/packp/report_status_test.go b/plumbing/protocol/packp/report_status_test.go
index 168d25b..1c3fa81 100644
--- a/plumbing/protocol/packp/report_status_test.go
+++ b/plumbing/protocol/packp/report_status_test.go
@@ -13,22 +13,25 @@ type ReportStatusSuite struct{}
 
 var _ = Suite(&ReportStatusSuite{})
 
-func (s *ReportStatusSuite) TestOk(c *C) {
+func (s *ReportStatusSuite) TestError(c *C) {
 	rs := NewReportStatus()
 	rs.UnpackStatus = "ok"
-	c.Assert(rs.Ok(), Equals, true)
+	c.Assert(rs.Error(), IsNil)
 	rs.UnpackStatus = "OK"
-	c.Assert(rs.Ok(), Equals, false)
+	c.Assert(rs.Error(), ErrorMatches, "unpack error: OK")
 	rs.UnpackStatus = ""
-	c.Assert(rs.Ok(), Equals, false)
+	c.Assert(rs.Error(), ErrorMatches, "unpack error: ")
+
+	cs := &CommandStatus{ReferenceName: plumbing.ReferenceName("ref")}
+	rs.UnpackStatus = "ok"
+	rs.CommandStatuses = append(rs.CommandStatuses, cs)
 
-	cs := &CommandStatus{}
 	cs.Status = "ok"
-	c.Assert(cs.Ok(), Equals, true)
+	c.Assert(rs.Error(), IsNil)
 	cs.Status = "OK"
-	c.Assert(cs.Ok(), Equals, false)
+	c.Assert(rs.Error(), ErrorMatches, "command error on ref: OK")
 	cs.Status = ""
-	c.Assert(cs.Ok(), Equals, false)
+	c.Assert(rs.Error(), ErrorMatches, "command error on ref: ")
 }
 
 func (s *ReportStatusSuite) testEncodeDecodeOk(c *C, rs *ReportStatus, lines ...string) {
diff --git a/plumbing/transport/internal/common/common.go b/plumbing/transport/internal/common/common.go
index f6d1249..17c473e 100644
--- a/plumbing/transport/internal/common/common.go
+++ b/plumbing/transport/internal/common/common.go
@@ -281,8 +281,8 @@ func (s *session) SendPack(req *packp.ReferenceUpdateRequest) (*packp.ReportStat
 		return nil, err
 	}
 
-	if !report.Ok() {
-		return report, fmt.Errorf("report status: %s", report.UnpackStatus)
+	if err := report.Error(); err != nil {
+		return report, err
 	}
 
 	return report, s.Command.Wait()
diff --git a/plumbing/transport/test/send_pack.go b/plumbing/transport/test/send_pack.go
index 8cb549d..f880588 100644
--- a/plumbing/transport/test/send_pack.go
+++ b/plumbing/transport/test/send_pack.go
@@ -131,7 +131,7 @@ func (s *SendPackSuite) TestFullSendPackOnNonEmpty(c *C) {
 	fixture := fixtures.Basic().ByTag("packfile").One()
 	req := packp.NewReferenceUpdateRequest()
 	req.Commands = []*packp.Command{
-		{"refs/heads/master", plumbing.ZeroHash, fixture.Head},
+		{"refs/heads/master", fixture.Head, fixture.Head},
 	}
 	s.sendPack(c, endpoint, req, fixture, full)
 	s.checkRemoteHead(c, endpoint, fixture.Head)
@@ -143,7 +143,7 @@ func (s *SendPackSuite) TestSendPackOnNonEmpty(c *C) {
 	fixture := fixtures.Basic().ByTag("packfile").One()
 	req := packp.NewReferenceUpdateRequest()
 	req.Commands = []*packp.Command{
-		{"refs/heads/master", plumbing.ZeroHash, fixture.Head},
+		{"refs/heads/master", fixture.Head, fixture.Head},
 	}
 	s.sendPack(c, endpoint, req, fixture, full)
 	s.checkRemoteHead(c, endpoint, fixture.Head)
@@ -155,7 +155,7 @@ func (s *SendPackSuite) TestSendPackOnNonEmptyWithReportStatus(c *C) {
 	fixture := fixtures.Basic().ByTag("packfile").One()
 	req := packp.NewReferenceUpdateRequest()
 	req.Commands = []*packp.Command{
-		{"refs/heads/master", plumbing.ZeroHash, fixture.Head},
+		{"refs/heads/master", fixture.Head, fixture.Head},
 	}
 	req.Capabilities.Set(capability.ReportStatus)
 
@@ -163,10 +163,30 @@ func (s *SendPackSuite) TestSendPackOnNonEmptyWithReportStatus(c *C) {
 	s.checkRemoteHead(c, endpoint, fixture.Head)
 }
 
-func (s *SendPackSuite) sendPack(c *C, ep transport.Endpoint,
-	req *packp.ReferenceUpdateRequest, fixture *fixtures.Fixture,
-	callAdvertisedReferences bool) {
+func (s *SendPackSuite) TestSendPackOnNonEmptyWithReportStatusWithError(c *C) {
+	endpoint := s.Endpoint
+	full := false
+	fixture := fixtures.Basic().ByTag("packfile").One()
+	req := packp.NewReferenceUpdateRequest()
+	req.Commands = []*packp.Command{
+		{"refs/heads/master", plumbing.ZeroHash, fixture.Head},
+	}
+	req.Capabilities.Set(capability.ReportStatus)
+
+	report, err := s.sendPackNoCheck(c, endpoint, req, fixture, full)
+	//XXX: Recent git versions return "failed to update ref", while older
+	//     (>=1.9) return "failed to lock".
+	c.Assert(err, ErrorMatches, ".*(failed to update ref|failed to lock).*")
+	c.Assert(report.UnpackStatus, Equals, "ok")
+	c.Assert(len(report.CommandStatuses), Equals, 1)
+	c.Assert(report.CommandStatuses[0].ReferenceName, Equals, plumbing.ReferenceName("refs/heads/master"))
+	c.Assert(report.CommandStatuses[0].Status, Matches, "(failed to update ref|failed to lock)")
+	s.checkRemoteHead(c, endpoint, fixture.Head)
+}
 
+func (s *SendPackSuite) sendPackNoCheck(c *C, ep transport.Endpoint,
+	req *packp.ReferenceUpdateRequest, fixture *fixtures.Fixture,
+	callAdvertisedReferences bool) (*packp.ReportStatus, error) {
 	url := ""
 	if fixture != nil {
 		url = fixture.URL
@@ -193,11 +213,28 @@ func (s *SendPackSuite) sendPack(c *C, ep transport.Endpoint,
 		req.Packfile = s.emptyPackfile()
 	}
 
-	report, err := r.SendPack(req)
+	return r.SendPack(req)
+}
+
+func (s *SendPackSuite) sendPack(c *C, ep transport.Endpoint,
+	req *packp.ReferenceUpdateRequest, fixture *fixtures.Fixture,
+	callAdvertisedReferences bool) {
+
+	url := ""
+	if fixture != nil {
+		url = fixture.URL
+	}
+
+	comment := Commentf(
+		"failed with ep=%s fixture=%s callAdvertisedReferences=%s",
+		ep.String(), url, callAdvertisedReferences,
+	)
+	report, err := s.sendPackNoCheck(c, ep, req, fixture, callAdvertisedReferences)
+
 	c.Assert(err, IsNil, comment)
 	if req.Capabilities.Supports(capability.ReportStatus) {
 		c.Assert(report, NotNil, comment)
-		c.Assert(report.Ok(), Equals, true, comment)
+		c.Assert(report.Error(), IsNil, comment)
 	} else {
 		c.Assert(report, IsNil, comment)
 	}