2 files changed, 27 insertions, 13 deletions

diff --git a/clients/common/common.go b/clients/common/common.go
index 8756cfd..460eb10 100644
--- a/clients/common/common.go
+++ b/clients/common/common.go
@@ -92,6 +92,17 @@ func (c *Capabilities) Decode(raw string) {
 	}
 }
 
+// Get returns the values for a capability
+func (c *Capabilities) Get(capability string) *Capability {
+	return c.m[capability]
+}
+
+// Set sets a capability removing the values
+func (c *Capabilities) Set(capability string, values ...string) {
+	delete(c.m, capability)
+	c.Add(capability, values...)
+}
+
 // Add adds a capability, values are optional
 func (c *Capabilities) Add(capability string, values ...string) {
 	if !c.Supports(capability) {
@@ -112,11 +123,6 @@ func (c *Capabilities) Supports(capability string) bool {
 	return ok
 }
 
-// Get returns the values for a capability
-func (c *Capabilities) Get(capability string) *Capability {
-	return c.m[capability]
-}
-
 // SymbolicReference returns the reference for a given symbolic reference
 func (c *Capabilities) SymbolicReference(sym string) string {
 	if !c.Supports("symref") {
@@ -170,7 +176,7 @@ func (c *Capabilities) String() string {
 
 type GitUploadPackInfo struct {
 	Capabilities *Capabilities
-	Head         string
+	Head         core.Hash
 	Refs         map[string]core.Hash
 }
 
@@ -221,8 +227,7 @@ func (r *GitUploadPackInfo) read(d *pktline.Decoder) error {
 
 func (r *GitUploadPackInfo) decodeHeaderLine(line string) {
 	parts := strings.SplitN(line, " HEAD", 2)
-
-	r.Head = parts[0]
+	r.Head = core.NewHash(parts[0])
 	r.Capabilities.Decode(line)
 }
 
@@ -251,7 +256,7 @@ func (r *GitUploadPackInfo) Bytes() []byte {
 	e := pktline.NewEncoder()
 	e.AddLine("# service=git-upload-pack")
 	e.AddFlush()
-	e.AddLine(fmt.Sprintf("%s HEAD\x00%s", r.Refs[r.Head].String(), r.Capabilities.String()))
+	e.AddLine(fmt.Sprintf("%s HEAD\x00%s", r.Head, r.Capabilities.String()))
 
 	for name, id := range r.Refs {
 		e.AddLine(fmt.Sprintf("%s %s", id, name))
diff --git a/clients/common/common_test.go b/clients/common/common_test.go
index 9529236..5ffb402 100644
--- a/clients/common/common_test.go
+++ b/clients/common/common_test.go
@@ -53,7 +53,7 @@ func (s *SuiteCommon) TestGitUploadPackInfo(c *C) {
 	ref := i.Capabilities.SymbolicReference("HEAD")
 	c.Assert(ref, Equals, "refs/heads/master")
 	c.Assert(i.Refs[ref].String(), Equals, "6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
-	c.Assert(i.Head, Equals, "6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
+	c.Assert(i.Head.String(), Equals, "6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
 }
 
 func (s *SuiteCommon) TestGitUploadPackInfoEmpty(c *C) {
@@ -73,7 +73,16 @@ func (s *SuiteCommon) TestCapabilitiesDecode(c *C) {
 	c.Assert(cap.Get("thin-pack").Values, DeepEquals, []string{""})
 }
 
-func (s *SuiteCommon) TestCapabilitiesString(c *C) {
+func (s *SuiteCommon) TestCapabilitiesSet(c *C) {
+	cap := NewCapabilities()
+	cap.Add("symref", "foo", "qux")
+	cap.Set("symref", "bar")
+
+	c.Assert(cap.m, HasLen, 1)
+	c.Assert(cap.Get("symref").Values, DeepEquals, []string{"bar"})
+}
+
+func (s *SuiteCommon) TestCapabilitiesAdd(c *C) {
 	cap := NewCapabilities()
 	cap.Add("symref", "foo", "qux")
 	cap.Add("thin-pack")
@@ -85,9 +94,9 @@ func (s *SuiteCommon) TestGitUploadPackEncode(c *C) {
 	info := NewGitUploadPackInfo()
 	info.Capabilities.Add("symref", "HEAD:refs/heads/master")
 
-	info.Head = "refs/heads/master"
+	info.Head = core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
 	info.Refs = map[string]core.Hash{
-		"refs/heads/master": core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"),
+		"refs/heads/master": info.Head,
 	}
 
 	c.Assert(info.String(), Equals,