prevent panic when logging error

Signed-off-by: Jörn Friedrich Dreyer <jfd@butonic.de>

changelog/unreleased/prevent-panic.md

@@ -0,0 +1,5 @@
+Bugfix: prevent a panic when logging an error
+
+We fixed a panic when constructing a path failed to get the parent for a node.
+
+https://github.com/cs3org/reva/pull/4954

pkg/storage/utils/decomposedfs/lookup/lookup.go

@@ -27,17 +27,18 @@ import (
 
 	user "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
 	provider "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
+	"github.com/google/uuid"
+	"github.com/pkg/errors"
+	"github.com/rogpeppe/go-internal/lockedfile"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/trace"
+
 	"github.com/cs3org/reva/v2/pkg/appctx"
 	"github.com/cs3org/reva/v2/pkg/errtypes"
 	"github.com/cs3org/reva/v2/pkg/storage/utils/decomposedfs/metadata"
 	"github.com/cs3org/reva/v2/pkg/storage/utils/decomposedfs/metadata/prefixes"
 	"github.com/cs3org/reva/v2/pkg/storage/utils/decomposedfs/node"
 	"github.com/cs3org/reva/v2/pkg/storage/utils/decomposedfs/options"
-	"github.com/google/uuid"
-	"github.com/pkg/errors"
-	"github.com/rogpeppe/go-internal/lockedfile"
-	"go.opentelemetry.io/otel"
-	"go.opentelemetry.io/otel/trace"
 )
 
 var tracer trace.Tracer
@@ -235,14 +236,17 @@ func (lu *Lookup) GenerateSpaceID(spaceType string, owner *user.User) (string, e
 // Path returns the path for node
 func (lu *Lookup) Path(ctx context.Context, n *node.Node, hasPermission node.PermissionFunc) (p string, err error) {
 	root := n.SpaceRoot
+	var child *node.Node
 	for n.ID != root.ID {
 		p = filepath.Join(n.Name, p)
+		child = n
 		if n, err = n.Parent(ctx); err != nil {
 			appctx.GetLogger(ctx).
 				Error().Err(err).
 				Str("path", p).
-				Str("spaceid", n.SpaceID).
-				Str("nodeid", n.ID).
+				Str("spaceid", child.SpaceID).
+				Str("nodeid", child.ID).
+				Str("parentid", child.ParentID).
 				Msg("Path()")
 			return
 		}