git: remote, Add shallow commits instead of substituting. Fixes #412

remote.go

@@ -976,9 +976,24 @@ func pushHashes(
 }
 
 func (r *Remote) updateShallow(o *FetchOptions, resp *packp.UploadPackResponse) error {
-	if o.Depth == 0 {
+	if o.Depth == 0 || len(resp.Shallows) == 0 {
 		return nil
 	}
 
-	return r.s.SetShallow(resp.Shallows)
+	shallows, err := r.s.Shallow()
+	if err != nil {
+		return err
+	}
+
+outer:
+	for _, s := range resp.Shallows {
+		for _, oldS := range shallows {
+			if s == oldS {
+				continue outer
+			}
+		}
+		shallows = append(shallows, s)
+	}
+
+	return r.s.SetShallow(shallows)
 }

remote_test.go

@@ -9,6 +9,7 @@ import (
 
 	"gopkg.in/src-d/go-git.v4/config"
 	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/protocol/packp"
 	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 	"gopkg.in/src-d/go-git.v4/storage"
 	"gopkg.in/src-d/go-git.v4/storage/filesystem"
@@ -741,3 +742,54 @@ func (s *RemoteSuite) TestList(c *C) {
 		c.Assert(found, Equals, true)
 	}
 }
+
+func (s *RemoteSuite) TestUpdateShallows(c *C) {
+	hashes := []plumbing.Hash{
+		plumbing.NewHash("0000000000000000000000000000000000000001"),
+		plumbing.NewHash("0000000000000000000000000000000000000002"),
+		plumbing.NewHash("0000000000000000000000000000000000000003"),
+		plumbing.NewHash("0000000000000000000000000000000000000004"),
+		plumbing.NewHash("0000000000000000000000000000000000000005"),
+		plumbing.NewHash("0000000000000000000000000000000000000006"),
+	}
+
+	tests := []struct {
+		hashes []plumbing.Hash
+		result []plumbing.Hash
+	}{
+		// add to empty shallows
+		{hashes[0:2], hashes[0:2]},
+		// add new hashes
+		{hashes[2:4], hashes[0:4]},
+		// add some hashes already in shallow list
+		{hashes[2:6], hashes[0:6]},
+		// add all hashes
+		{hashes[0:6], hashes[0:6]},
+		// add empty list
+		{nil, hashes[0:6]},
+	}
+
+	remote := newRemote(memory.NewStorage(), &config.RemoteConfig{
+		Name: DefaultRemoteName,
+	})
+
+	shallows, err := remote.s.Shallow()
+	c.Assert(err, IsNil)
+	c.Assert(len(shallows), Equals, 0)
+
+	resp := new(packp.UploadPackResponse)
+	o := &FetchOptions{
+		Depth: 1,
+	}
+
+	for _, t := range tests {
+		resp.Shallows = t.hashes
+		err = remote.updateShallow(o, resp)
+		c.Assert(err, IsNil)
+
+		shallow, err := remote.s.Shallow()
+		c.Assert(err, IsNil)
+		c.Assert(len(shallow), Equals, len(t.result))
+		c.Assert(shallow, DeepEquals, t.result)
+	}
+}

repository_test.go

@@ -1615,3 +1615,66 @@ func executeOnPath(path, cmd string) error {
 
 	return c.Run()
 }
+
+func (s *RepositorySuite) TestBrokenMultipleShallowFetch(c *C) {
+	r, _ := Init(memory.NewStorage(), nil)
+	_, err := r.CreateRemote(&config.RemoteConfig{
+		Name: DefaultRemoteName,
+		URLs: []string{s.GetBasicLocalRepositoryURL()},
+	})
+	c.Assert(err, IsNil)
+
+	c.Assert(r.Fetch(&FetchOptions{
+		Depth:    2,
+		RefSpecs: []config.RefSpec{config.RefSpec("refs/heads/master:refs/heads/master")},
+	}), IsNil)
+
+	shallows, err := r.Storer.Shallow()
+	c.Assert(err, IsNil)
+	c.Assert(len(shallows), Equals, 1)
+
+	ref, err := r.Reference("refs/heads/master", true)
+	c.Assert(err, IsNil)
+	cobj, err := r.CommitObject(ref.Hash())
+	c.Assert(err, IsNil)
+	c.Assert(cobj, NotNil)
+	err = object.NewCommitPreorderIter(cobj, nil, nil).ForEach(func(c *object.Commit) error {
+		for _, ph := range c.ParentHashes {
+			for _, h := range shallows {
+				if ph == h {
+					return storer.ErrStop
+				}
+			}
+		}
+
+		return nil
+	})
+	c.Assert(err, IsNil)
+
+	c.Assert(r.Fetch(&FetchOptions{
+		Depth:    5,
+		RefSpecs: []config.RefSpec{config.RefSpec("refs/heads/*:refs/heads/*")},
+	}), IsNil)
+
+	shallows, err = r.Storer.Shallow()
+	c.Assert(err, IsNil)
+	c.Assert(len(shallows), Equals, 3)
+
+	ref, err = r.Reference("refs/heads/master", true)
+	c.Assert(err, IsNil)
+	cobj, err = r.CommitObject(ref.Hash())
+	c.Assert(err, IsNil)
+	c.Assert(cobj, NotNil)
+	err = object.NewCommitPreorderIter(cobj, nil, nil).ForEach(func(c *object.Commit) error {
+		for _, ph := range c.ParentHashes {
+			for _, h := range shallows {
+				if ph == h {
+					return storer.ErrStop
+				}
+			}
+		}
+
+		return nil
+	})
+	c.Assert(err, IsNil)
+}