repository: Allow voting on missing config

While not likely, it could be that a repository is missing a gitconfig
due to whatever reason. While we can mostly cope with it just fine, in
the context of transactional voting it would mean that voting fails
because we cannot retrieve the file's contents to compute the vote.

Fix this issue by handling the case where the config doesn't exist via a
constructed vote on an artificial value.

Changelog: fixed

1 files changed, 16 insertions, 11 deletions

diff --git a/internal/gitaly/service/repository/config.go b/internal/gitaly/service/repository/config.go
index bfa69123e..452eabb82 100644
--- a/internal/gitaly/service/repository/config.go
+++ b/internal/gitaly/service/repository/config.go
@@ -192,19 +192,24 @@ func (s *server) voteOnConfig(ctx context.Context, repo *gitalypb.Repository) er
 			return fmt.Errorf("get repo path: %w", err)
 		}
 
-		config, err := os.Open(filepath.Join(repoPath, "config"))
-		if err != nil {
-			return fmt.Errorf("open repo config: %w", err)
-		}
+		var vote voting.Vote
 
-		hash := voting.NewVoteHash()
-		if _, err := io.Copy(hash, config); err != nil {
-			return fmt.Errorf("seeding vote: %w", err)
-		}
+		config, err := os.Open(filepath.Join(repoPath, "config"))
+		switch {
+		case err == nil:
+			hash := voting.NewVoteHash()
+			if _, err := io.Copy(hash, config); err != nil {
+				return fmt.Errorf("seeding vote: %w", err)
+			}
 
-		vote, err := hash.Vote()
-		if err != nil {
-			return fmt.Errorf("computing vote: %w", err)
+			vote, err = hash.Vote()
+			if err != nil {
+				return fmt.Errorf("computing vote: %w", err)
+			}
+		case os.IsNotExist(err):
+			vote = voting.VoteFromData([]byte("notfound"))
+		default:
+			return fmt.Errorf("open repo config: %w", err)
 		}
 
 		if err := s.txManager.Vote(ctx, tx, vote); err != nil {