fix(manifest-repo-export-service): Changed fetch from HEAD to direct …

…reference (#2055)

The manifest repo export service fetches the reference to the current
commit directly in all of the code base. Updated this fetch the HEAD to
get the specific reference for consistency.
Ref: SRX-B66T2N

services/manifest-repo-export-service/pkg/cmd/server.go

@@ -344,11 +344,11 @@ func processEsls(ctx context.Context, repo repository.Repository, dbHandler *db.
 				}
 
 				//Get latest commit. Write esl timestamp and commit hash.
-				commit, err := repo.GetHeadCommit()
+				commitId, err := repo.GetHeadCommitId()
 				if err != nil {
 					return err
 				}
-				return dbHandler.DBWriteCommitTransactionTimestamp(ctx, transaction, commit.Id().String(), esl.Created)
+				return dbHandler.DBWriteCommitTransactionTimestamp(ctx, transaction, commitId.String(), esl.Created)
 			})
 			if err != nil {
 				err3 := repo.FetchAndReset(ctx)

services/manifest-repo-export-service/pkg/repository/repository.go

@@ -62,7 +62,7 @@ type Repository interface {
 	StateAt(oid *git.Oid) (*State, error)
 	FetchAndReset(ctx context.Context) error
 	PushRepo(ctx context.Context) error
-	GetHeadCommit() (*git.Commit, error)
+	GetHeadCommitId() (*git.Oid, error)
 }
 
 type TransformerBatchApplyError struct {
@@ -418,17 +418,13 @@ func (r *repository) PushRepo(ctx context.Context) error {
 	return nil
 }
 
-func (r *repository) GetHeadCommit() (*git.Commit, error) {
-	ref, err := r.repository.Head()
+func (r *repository) GetHeadCommitId() (*git.Oid, error) {
+	branchHead := fmt.Sprintf("refs/heads/%s", r.config.Branch)
+	ref, err := r.repository.References.Lookup(branchHead)
 	if err != nil {
-		return nil, fmt.Errorf("Error fetching HEAD: %v", err)
+		return nil, fmt.Errorf("Error fetching reference \"%s\": %v", branchHead, err)
 	}
-	commit, err := r.repository.LookupCommit(ref.Target())
-	if err != nil {
-		return nil, fmt.Errorf("Error transalting into commit: %v", err)
-	}
-	return commit, nil
-
+	return ref.Target(), nil
 }
 
 func (r *repository) ApplyTransformersInternal(ctx context.Context, transaction *sql.Tx, transformer Transformer) ([]string, *State, []*TransformerResult, *TransformerBatchApplyError) {