From 75da83739f25f528bf242341d62e01b773329470 Mon Sep 17 00:00:00 2001
From: Javi Fontan <jfontan@gmail.com>
Date: Mon, 16 Apr 2018 19:01:49 +0200
Subject: [PATCH] git: remote, Add shallow commits instead of substituting.
 Fixes #412

updateShallow substituted the previous shallow list with the one
returned by the UploadPackResponse. If the repository had previous
shallow commits these are deleted from the list.

This change adds the new shallow hashes to the old ones.

Signed-off-by: Javi Fontan <jfontan@gmail.com>
---
 remote.go          | 19 ++++++++++++--
 remote_test.go     | 52 ++++++++++++++++++++++++++++++++++++++
 repository_test.go | 63 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 132 insertions(+), 2 deletions(-)

diff --git a/remote.go b/remote.go
index 666c9f5eb..4b86955e8 100644
--- a/remote.go
+++ b/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)
 }
diff --git a/remote_test.go b/remote_test.go
index e586e7a7d..82ec1fc29 100644
--- a/remote_test.go
+++ b/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)
+	}
+}
diff --git a/repository_test.go b/repository_test.go
index c98e2acf2..be7f16365 100644
--- a/repository_test.go
+++ b/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)
+}