ProvisionedDashboard: Fix backend fails to delete dashboard due to missing branch and file

pkg/registry/apis/provisioning/repository/github.go

@@ -45,6 +45,7 @@ type GithubRepository interface {
 	Owner() string
 	Repo() string
 	Client() pgh.Client
+	EnsureBranchExists(ctx context.Context, branchName string) error
 }
 
 func NewGitHub(
@@ -279,7 +280,7 @@ func (r *githubRepository) Create(ctx context.Context, path, ref string, data []
 	}
 	ctx, _ = r.logger(ctx, ref)
 
-	if err := r.ensureBranchExists(ctx, ref); err != nil {
+	if err := r.EnsureBranchExists(ctx, ref); err != nil {
 		return err
 	}
 
@@ -314,7 +315,7 @@ func (r *githubRepository) Update(ctx context.Context, path, ref string, data []
 	}
 	ctx, _ = r.logger(ctx, ref)
 
-	if err := r.ensureBranchExists(ctx, ref); err != nil {
+	if err := r.EnsureBranchExists(ctx, ref); err != nil {
 		return err
 	}
 
@@ -365,7 +366,7 @@ func (r *githubRepository) Delete(ctx context.Context, path, ref, comment string
 	}
 	ctx, _ = r.logger(ctx, ref)
 
-	if err := r.ensureBranchExists(ctx, ref); err != nil {
+	if err := r.EnsureBranchExists(ctx, ref); err != nil {
 		return err
 	}
 
@@ -482,7 +483,7 @@ func isValidGitBranchName(branch string) bool {
 	return true
 }
 
-func (r *githubRepository) ensureBranchExists(ctx context.Context, branchName string) error {
+func (r *githubRepository) EnsureBranchExists(ctx context.Context, branchName string) error {
 	if !isValidGitBranchName(branchName) {
 		return &apierrors.StatusError{
 			ErrStatus: metav1.Status{

pkg/registry/apis/provisioning/resources/dualwriter.go

@@ -81,6 +81,13 @@ func (r *DualReadWriter) Delete(ctx context.Context, opts DualWriteOptions) (*Pa
 		return nil, fmt.Errorf("folder delete not supported")
 	}
 
+	// First ensure the branch exists if we're using a GitHub repository
+	if githubRepo, ok := r.repo.(repository.GithubRepository); ok && opts.Ref != "" {
+		if err := githubRepo.EnsureBranchExists(ctx, opts.Ref); err != nil {
+			return nil, fmt.Errorf("ensure branch exists: %w", err)
+		}
+	}
+
 	file, err := r.repo.Read(ctx, opts.Path, opts.Ref)
 	if err != nil {
 		return nil, fmt.Errorf("read file: %w", err)