filer: keep a renamed entry's old object when the path lookup fails

The deferred delete must only run once the lookup shows no remote-only
entry at the old path. A failed lookup shows nothing, and an extra
object loses nothing.

weed/server/filer_grpc_server_rename.go

@@ -2,6 +2,7 @@ package weed_server
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"maps"
 	"path/filepath"
@@ -159,11 +160,18 @@ func (event metadataEvent) notify(f *filer.Filer, ctx context.Context, signature
 	if event.deleteOldRemote {
 		// a child path is not locked by its directory's rename, so another
 		// rename may have put a remote-only entry at the old key meanwhile;
-		// the store is asked directly, a lazy fetch would revive the old key
-		if current, err := f.Store.FindEntry(ctx, event.oldEntry.FullPath); err == nil && current.IsInRemoteOnly() {
+		// the store is asked directly, a lazy fetch would revive the old key.
+		// When in doubt the object stays: an extra object loses nothing.
+		current, findErr := f.Store.FindEntry(ctx, event.oldEntry.FullPath)
+		switch {
+		case findErr != nil && !errors.Is(findErr, filer_pb.ErrNotFound):
+			glog.WarningfCtx(ctx, "keep remote object of renamed %s: look up its old path: %v", event.oldEntry.FullPath, findErr)
+		case findErr == nil && current.IsInRemoteOnly():
 			glog.V(0).InfofCtx(ctx, "keep remote object of renamed %s: a remote-only entry has taken its path", event.oldEntry.FullPath)
-		} else if err := f.DeleteFromRemote(ctx, event.oldEntry); err != nil {
-			glog.WarningfCtx(ctx, "delete remote object of renamed %s: %v", event.oldEntry.FullPath, err)
+		default:
+			if err := f.DeleteFromRemote(ctx, event.oldEntry); err != nil {
+				glog.WarningfCtx(ctx, "delete remote object of renamed %s: %v", event.oldEntry.FullPath, err)
+			}
 		}
 	}
 	f.NotifyUpdateEvent(ctx, event.oldEntry, event.newEntry, event.deleteChunks, false, signatures)

weed/server/filer_grpc_server_rename_remote_test.go

@@ -304,7 +304,13 @@ func TestDeferredOldKeyDeleteKeepsAKeyRetakenSince(t *testing.T) {
 	event.notify(server.filer, context.Background(), nil)
 	assert.Empty(t, client.recorded())
 
+	// a lookup that fails says nothing about the path
 	delete(store.entries, "/buckets/b/src/a.jpg")
+	store.findErr = errors.New("store unavailable")
+	event.notify(server.filer, context.Background(), nil)
+	assert.Empty(t, client.recorded())
+
+	store.findErr = nil
 	event.notify(server.filer, context.Background(), nil)
 	assert.Equal(t, []string{"delete origin/src/a.jpg"}, client.recorded())
 }

weed/server/filer_grpc_server_rename_test.go

@@ -31,6 +31,7 @@ type renameTestStore struct {
 	deleteErr error
 	listErr   error         // simulates a transient store/RPC failure from a directory listing
 	findDelay time.Duration // optional: widen check-then-act windows in tests
+	findErr   error         // simulates a failing entry lookup
 }
 
 func newRenameTestStore() *renameTestStore {
@@ -77,6 +78,9 @@ func (s *renameTestStore) FindEntry(_ context.Context, p util.FullPath) (*filer.
 	s.mu.Lock()
 	defer s.mu.Unlock()
 	s.findCalls[string(p)]++
+	if s.findErr != nil {
+		return nil, s.findErr
+	}
 	entry, found := s.entries[string(p)]
 	if !found {
 		return nil, filer_pb.ErrNotFound