helm/internal: add `ErrChartReference`

This makes it possible to signal reference (validation) errors
happening before the build process actually starts dealing with
the chart.

At present, this does not have a more specific counterpart in the API,
but this is expected to change when the conditions logic is revised.

Signed-off-by: Hidde Beydals <hello@hidde.co>

internal/helm/chart/builder_local.go

@@ -65,11 +65,12 @@ func NewLocalBuilder(dm *DependencyManager) Builder {
 func (b *localChartBuilder) Build(ctx context.Context, ref Reference, p string, opts BuildOptions) (*Build, error) {
 	localRef, ok := ref.(LocalReference)
 	if !ok {
-		return nil, fmt.Errorf("expected local chart reference")
+		err := fmt.Errorf("expected local chart reference")
+		return nil, &BuildError{Reason: ErrChartReference, Err: err}
 	}
 
 	if err := ref.Validate(); err != nil {
-		return nil, &BuildError{Reason: ErrChartPull, Err: err}
+		return nil, &BuildError{Reason: ErrChartReference, Err: err}
 	}
 
 	// Load the chart metadata from the LocalReference to ensure it points

internal/helm/chart/builder_remote.go

@@ -64,11 +64,12 @@ func NewRemoteBuilder(repository *repository.ChartRepository) Builder {
 func (b *remoteChartBuilder) Build(_ context.Context, ref Reference, p string, opts BuildOptions) (*Build, error) {
 	remoteRef, ok := ref.(RemoteReference)
 	if !ok {
-		return nil, fmt.Errorf("expected remote chart reference")
+		err := fmt.Errorf("expected remote chart reference")
+		return nil, &BuildError{Reason: ErrChartReference, Err: err}
 	}
 
 	if err := ref.Validate(); err != nil {
-		return nil, &BuildError{Reason: ErrChartPull, Err: err}
+		return nil, &BuildError{Reason: ErrChartReference, Err: err}
 	}
 
 	if err := b.remote.LoadFromCache(); err != nil {

internal/helm/chart/errors.go

@@ -61,6 +61,7 @@ func (e *BuildError) Unwrap() error {
 }
 
 var (
+	ErrChartReference     = BuildErrorReason("chart reference error")
 	ErrChartPull          = BuildErrorReason("chart pull error")
 	ErrChartMetadataPatch = BuildErrorReason("chart metadata patch error")
 	ErrValuesFilesMerge   = BuildErrorReason("values files merge error")