git2go: Improve error messages when looking up commits

The current error messages when lookup of commits fails doesn't give any
hint what reference was actually looked up, which makes it harder than
necessary to understand the context.

Fix this by adding the reference name to those error messages.

1 files changed, 3 insertions, 3 deletions

diff --git a/cmd/gitaly-git2go/util.go b/cmd/gitaly-git2go/util.go
index d580582cd..a315c5f3a 100644
--- a/cmd/gitaly-git2go/util.go
+++ b/cmd/gitaly-git2go/util.go
@@ -11,17 +11,17 @@ import (
 func lookupCommit(repo *git.Repository, ref string) (*git.Commit, error) {
 	object, err := repo.RevparseSingle(ref)
 	if err != nil {
-		return nil, fmt.Errorf("could not lookup reference: %w", err)
+		return nil, fmt.Errorf("could not lookup reference %q: %w", ref, err)
 	}
 
 	peeled, err := object.Peel(git.ObjectCommit)
 	if err != nil {
-		return nil, fmt.Errorf("could not peel reference: %w", err)
+		return nil, fmt.Errorf("could not peel reference %q: %w", ref, err)
 	}
 
 	commit, err := peeled.AsCommit()
 	if err != nil {
-		return nil, fmt.Errorf("could not cast to commit: %w", err)
+		return nil, fmt.Errorf("reference %q is not a commit: %w", ref, err)
 	}
 
 	return commit, nil