repository: Fix default refspec for FetchRemote

in case a RemoteParam as passed to FetchRemote, we intend do use its
MirrorRefmaps to determine how references should be mirrored, as there
is no configured remote which could have a refspec. In case no map is
provided, we should fall back to just doing a mirror-fetch, if one goes
by what the Ruby RPC did back when it still existed. But in fact we
don't set up a refspec at all in that case, which instead causes us to
simply fetch the remote's HEAD reference.

Fix this issue by using "refs/*:refs/*" in case no refspec is given.

2 files changed, 51 insertions, 0 deletions

diff --git a/internal/gitaly/service/repository/fetch_remote.go b/internal/gitaly/service/repository/fetch_remote.go
index 7eefa0b03..ad3d72901 100644
--- a/internal/gitaly/service/repository/fetch_remote.go
+++ b/internal/gitaly/service/repository/fetch_remote.go
@@ -203,6 +203,10 @@ func (s *server) validateFetchRemoteRequest(req *gitalypb.FetchRemoteRequest) er
 }
 
 func (s *server) getRefspecs(refmaps []string) []string {
+	if len(refmaps) == 0 {
+		return []string{"+refs/*:refs/*"}
+	}
+
 	refspecs := make([]string, 0, len(refmaps))
 
 	for _, refmap := range refmaps {
diff --git a/internal/gitaly/service/repository/fetch_remote_test.go b/internal/gitaly/service/repository/fetch_remote_test.go
index c0577df6a..7614e9458 100644
--- a/internal/gitaly/service/repository/fetch_remote_test.go
+++ b/internal/gitaly/service/repository/fetch_remote_test.go
@@ -13,6 +13,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"gitlab.com/gitlab-org/gitaly/internal/git"
 	"gitlab.com/gitlab-org/gitaly/internal/gitaly/config"
 	"gitlab.com/gitlab-org/gitaly/internal/helper/text"
 	"gitlab.com/gitlab-org/gitaly/internal/storage"
@@ -73,6 +74,52 @@ func TestFetchRemoteSuccess(t *testing.T) {
 	require.Equal(t, resp.TagsChanged, true)
 }
 
+func TestFetchRemote_withDefaultRefmaps(t *testing.T) {
+	locator := config.NewLocator(config.Config)
+	serverSocketPath, stop := runRepoServer(t, locator, testhelper.WithInternalSocket(config.Config))
+	defer stop()
+
+	client, conn := newRepositoryClient(t, serverSocketPath)
+	defer conn.Close()
+
+	sourceRepoProto, sourceRepoPath, cleanup := testhelper.NewTestRepo(t)
+	defer cleanup()
+	sourceRepo := git.NewRepository(sourceRepoProto, config.Config)
+
+	targetRepoProto, targetRepoPath := copyRepoWithNewRemote(t, sourceRepoProto, locator, "my-remote")
+	defer func() {
+		require.NoError(t, os.RemoveAll(targetRepoPath))
+	}()
+	targetRepo := git.NewRepository(targetRepoProto, config.Config)
+
+	port, stopGitServer := testhelper.GitServer(t, config.Config, sourceRepoPath, nil)
+	defer func() { require.NoError(t, stopGitServer()) }()
+
+	ctx, cancel := testhelper.Context()
+	defer cancel()
+
+	require.NoError(t, sourceRepo.UpdateRef(ctx, "refs/heads/foobar", "refs/heads/master", ""))
+
+	// With no refmap given, FetchRemote should fall back to
+	// "refs/heads/*:refs/heads/*" and thus mirror what's in the source
+	// repository.
+	resp, err := client.FetchRemote(ctx, &gitalypb.FetchRemoteRequest{
+		Repository: targetRepoProto,
+		RemoteParams: &gitalypb.Remote{
+			Url:  fmt.Sprintf("http://127.0.0.1:%d/%s", port, filepath.Base(sourceRepoPath)),
+			Name: "my-remote",
+		},
+	})
+	require.NoError(t, err)
+	require.NotNil(t, resp)
+
+	sourceRefs, err := sourceRepo.GetReferences(ctx, "")
+	require.NoError(t, err)
+	targetRefs, err := targetRepo.GetReferences(ctx, "")
+	require.NoError(t, err)
+	require.Equal(t, sourceRefs, targetRefs)
+}
+
 func TestFetchRemoteFailure(t *testing.T) {
 	repo, _, cleanup := testhelper.NewTestRepo(t)
 	defer cleanup()