.

go/zodb/storage/demo/demo.go

@@ -49,7 +49,7 @@ type Storage struct {
 
 
 // Close implements zodb.IStorageDriver .
-func (ovl *Storage) Close() error {
+func (ovl *Storage) Close() error {		// XXX ovl -> d ?
 	// XXX errctx?
 
 	err1 := ovl.δ.Close()
@@ -76,13 +76,17 @@ func (ovl *Storage) Sync(ctx context.Context) (head zodb.Tid, _ error) {
 }
 
 // Load implements zodb.IStorageDriver .
-func (ovl *Storage) Load(ctx context.Context, xid zodb.Xid) (*mem.Buf, zodb.Tid, error) {
-	// XXX errctx?
+func (ovl *Storage) Load(ctx context.Context, xid zodb.Xid) (_ *mem.Buf, _ zodb.Tid, err error) {
+	defer func() {
+		if err != nil {
+			err = &zodb.OpError{URL: ovl.URL(), Op: "load", Args: xid, Err: err}
+		}
+	}()
 
 	data, serial, err := ovl.δ.Load(ctx, xid)
-	if data != nil {
+	if err == nil {
 		// object data is present in δ
-		return data, serial, err
+		return data, serial, nil
 	}
 
 	useBase := false
@@ -92,7 +96,7 @@ func (ovl *Storage) Load(ctx context.Context, xid zodb.Xid) (*mem.Buf, zodb.Tid,
 	case errors.As(err, &eNoData):
 		if eNoData.DeletedAt != 0 {
 			// object deleted in δ -> whiteout
-			return data, serial, err
+			return data, serial, eNoData
 		} else {
 			// object not created in δ
 			useBase = true
@@ -109,6 +113,17 @@ func (ovl *Storage) Load(ctx context.Context, xid zodb.Xid) (*mem.Buf, zodb.Tid,
 
 	// XXX cap .at in xid to base.At0 ? (and convert back on error return)
 	data, serial, err = ovl.base.Load(ctx, xid)
+	if err == nil {
+		return data, serial, nil
+	}
+
+	switch {
+	case errors.As(err, &eNoData):
+		err = eNoData
+	case errors.As(err, &eNoObject):
+		err = eNoObject
+	}
+
 	return data, serial, err
 }