Remote: add Prune option to PushOptions

config/refspec.go

@@ -127,6 +127,13 @@ func (s RefSpec) Dst(n plumbing.ReferenceName) plumbing.ReferenceName {
 	return plumbing.ReferenceName(dst[0:wd] + match + dst[wd+1:])
 }
 
+func (s RefSpec) Reverse() RefSpec {
+	spec := string(s)
+	separator := strings.Index(spec, refSpecSeparator)
+
+	return RefSpec(spec[separator+1:] + refSpecSeparator + spec[:separator])
+}
+
 func (s RefSpec) String() string {
 	return string(s)
 }

config/refspec_test.go

@@ -116,6 +116,15 @@ func (s *RefSpecSuite) TestRefSpecDstBlob(c *C) {
 		"refs/remotes/origin/foo",
 	)
 }
+
+func (s *RefSpecSuite) TestRefSpecReverse(c *C) {
+	spec := RefSpec("refs/heads/*:refs/remotes/origin/*")
+	c.Assert(
+		spec.Reverse(), Equals,
+		RefSpec("refs/remotes/origin/*:refs/heads/*"),
+	)
+}
+
 func (s *RefSpecSuite) TestMatchAny(c *C) {
 	specs := []RefSpec{
 		"refs/heads/bar:refs/remotes/origin/foo",

options.go

@@ -186,6 +186,9 @@ type PushOptions struct {
 	// Progress is where the human readable information sent by the server is
 	// stored, if nil nothing is stored.
 	Progress sideband.Progress
+	// Prune specify that remote refs that match given RefSpecs and that do
+	// not exist locally will be removed.
+	Prune bool
 }
 
 // Validate validates the fields and sets the default values.

remote.go

@@ -168,7 +168,17 @@ func (r *Remote) PushContext(ctx context.Context, o *PushOptions) (err error) {
 		}
 	}
 
-	rs, err := pushHashes(ctx, s, r.s, req, hashesToPush, r.useRefDeltas(ar))
+	if len(hashesToPush) == 0 {
+		allDelete = true
+		for _, command := range req.Commands {
+			if command.Action() != packp.Delete {
+				allDelete = false
+				break
+			}
+		}
+	}
+
+	rs, err := pushHashes(ctx, s, r.s, req, hashesToPush, r.useRefDeltas(ar), allDelete)
 	if err != nil {
 		return err
 	}
@@ -201,7 +211,7 @@ func (r *Remote) newReferenceUpdateRequest(
 		}
 	}
 
-	if err := r.addReferencesToUpdate(o.RefSpecs, localRefs, remoteRefs, req); err != nil {
+	if err := r.addReferencesToUpdate(o.RefSpecs, localRefs, remoteRefs, req, o.Prune); err != nil {
 		return nil, err
 	}
 
@@ -389,6 +399,7 @@ func (r *Remote) addReferencesToUpdate(
 	localRefs []*plumbing.Reference,
 	remoteRefs storer.ReferenceStorer,
 	req *packp.ReferenceUpdateRequest,
+	prune bool,
 ) error {
 	// This references dictionary will be used to search references by name.
 	refsDict := make(map[string]*plumbing.Reference)
@@ -398,14 +409,20 @@ func (r *Remote) addReferencesToUpdate(
 
 	for _, rs := range refspecs {
 		if rs.IsDelete() {
-			if err := r.deleteReferences(rs, remoteRefs, req); err != nil {
+			if err := r.deleteReferences(rs, remoteRefs, refsDict, req, false); err != nil {
 				return err
 			}
 		} else {
 			err := r.addOrUpdateReferences(rs, localRefs, refsDict, remoteRefs, req)
 			if err != nil {
 				return err
 			}
+
+			if prune {
+				if err := r.deleteReferences(rs, remoteRefs, refsDict, req, true); err != nil {
+					return err
+				}
+			}
 		}
 	}
 
@@ -441,7 +458,10 @@ func (r *Remote) addOrUpdateReferences(
 }
 
 func (r *Remote) deleteReferences(rs config.RefSpec,
-	remoteRefs storer.ReferenceStorer, req *packp.ReferenceUpdateRequest) error {
+	remoteRefs storer.ReferenceStorer,
+	refsDict map[string]*plumbing.Reference,
+	req *packp.ReferenceUpdateRequest,
+	prune bool) error {
 	iter, err := remoteRefs.IterReferences()
 	if err != nil {
 		return err
@@ -452,8 +472,19 @@ func (r *Remote) deleteReferences(rs config.RefSpec,
 			return nil
 		}
 
-		if rs.Dst("") != ref.Name() {
-			return nil
+		if prune {
+			rs := rs.Reverse()
+			if !rs.Match(ref.Name()) {
+				return nil
+			}
+
+			if _, ok := refsDict[rs.Dst(ref.Name()).String()]; ok {
+				return nil
+			}
+		} else {
+			if rs.Dst("") != ref.Name() {
+				return nil
+			}
 		}
 
 		cmd := &packp.Command{
@@ -1012,10 +1043,11 @@ func pushHashes(
 	req *packp.ReferenceUpdateRequest,
 	hs []plumbing.Hash,
 	useRefDeltas bool,
+	allDelete bool,
 ) (*packp.ReportStatus, error) {
 
 	rd, wr := io.Pipe()
-	req.Packfile = rd
+
 	config, err := s.Config()
 	if err != nil {
 		return nil, err
@@ -1026,15 +1058,20 @@ func pushHashes(
 	// to the channel.
 	done := make(chan error, 1)
 
-	go func() {
-		e := packfile.NewEncoder(wr, s, useRefDeltas)
-		if _, err := e.Encode(hs, config.Pack.Window); err != nil {
-			done <- wr.CloseWithError(err)
-			return
-		}
+	if !allDelete {
+		req.Packfile = rd
+		go func() {
+			e := packfile.NewEncoder(wr, s, useRefDeltas)
+			if _, err := e.Encode(hs, config.Pack.Window); err != nil {
+				done <- wr.CloseWithError(err)
+				return
+			}
 
-		done <- wr.Close()
-	}()
+			done <- wr.Close()
+		}()
+	} else {
+		close(done)
+	}
 
 	rs, err := sess.ReceivePack(ctx, req)
 	if err != nil {

remote_test.go

@@ -21,7 +21,7 @@ import (
 
 	. "gopkg.in/check.v1"
 	"gopkg.in/src-d/go-billy.v4/osfs"
-	"gopkg.in/src-d/go-git-fixtures.v3"
+	fixtures "gopkg.in/src-d/go-git-fixtures.v3"
 )
 
 type RemoteSuite struct {
@@ -583,6 +583,63 @@ func (s *RemoteSuite) TestPushForce(c *C) {
 	c.Assert(newRef, Not(DeepEquals), oldRef)
 }
 
+func (s *RemoteSuite) TestPushPrune(c *C) {
+	fs := fixtures.Basic().One().DotGit()
+	url := c.MkDir()
+	server, err := PlainClone(url, true, &CloneOptions{
+		URL: fs.Root(),
+	})
+	c.Assert(err, IsNil)
+
+	r, err := PlainClone(c.MkDir(), true, &CloneOptions{
+		URL: url,
+	})
+	c.Assert(err, IsNil)
+
+	tag, err := r.Reference(plumbing.ReferenceName("refs/tags/v1.0.0"), true)
+	c.Assert(err, IsNil)
+
+	err = r.DeleteTag("v1.0.0")
+	c.Assert(err, IsNil)
+
+	remote, err := r.Remote(DefaultRemoteName)
+	c.Assert(err, IsNil)
+
+	ref, err := r.Reference(plumbing.ReferenceName("refs/heads/master"), true)
+	c.Assert(err, IsNil)
+
+	err = remote.Push(&PushOptions{
+		RefSpecs: []config.RefSpec{
+			config.RefSpec("refs/heads/*:refs/heads/*"),
+		},
+		Prune: true,
+	})
+	c.Assert(err, Equals, NoErrAlreadyUpToDate)
+
+	AssertReferences(c, server, map[string]string{
+		"refs/tags/v1.0.0": tag.Hash().String(),
+	})
+
+	err = remote.Push(&PushOptions{
+		RefSpecs: []config.RefSpec{
+			config.RefSpec("*:*"),
+		},
+		Prune: true,
+	})
+	c.Assert(err, IsNil)
+
+	AssertReferences(c, server, map[string]string{
+		"refs/remotes/origin/master": ref.Hash().String(),
+	})
+
+	AssertReferences(c, server, map[string]string{
+		"refs/remotes/origin/master": ref.Hash().String(),
+	})
+
+	ref, err = server.Reference(plumbing.ReferenceName("refs/tags/v1.0.0"), true)
+	c.Assert(err, Equals, plumbing.ErrReferenceNotFound)
+}
+
 func (s *RemoteSuite) TestPushNewReference(c *C) {
 	fs := fixtures.Basic().One().DotGit()
 	url := c.MkDir()