fix(s3): use recursive delete for .versions directory cleanup (#8887)

* fix(s3): use recursive delete for .versions directory cleanup

When only delete markers remain in a .versions directory,
updateLatestVersionAfterDeletion tried to delete it non-recursively,
which failed with "fail to delete non-empty folder" because the delete
marker entries were still present. Use recursive deletion so the
directory and its remaining delete marker entries are cleaned up together.

* fix(s3): guard .versions directory deletion against truncated listings

When the version listing is truncated (>1000 entries), content versions
may exist beyond the first page. Skip the recursive directory deletion
in this case to prevent data loss.

* fix(s3): preserve delete markers in .versions directory

Delete markers must be preserved per S3 semantics — they are only
removed by an explicit DELETE with versionId. The previous fix would
recursively delete the entire .versions directory (including delete
markers) when no content versions were found.

Now the logic distinguishes three cases:
1. Content versions exist → update latest version metadata
2. Only delete markers remain (or listing truncated) → keep directory
3. Truly empty → safe to delete directory (non-recursive)

weed/s3api/s3api_object_versioning.go

@@ -999,7 +999,7 @@ func (s3a *S3ApiServer) updateLatestVersionAfterDeletion(bucket, object string)
 	glog.V(1).Infof("updateLatestVersionAfterDeletion: updating latest version for %s/%s, listing %s", bucket, object, versionsDir)
 
 	// List all remaining version files in the .versions directory
-	entries, _, err := s3a.list(versionsDir, "", "", false, 1000)
+	entries, isLast, err := s3a.list(versionsDir, "", "", false, 1000)
 	if err != nil {
 		glog.Errorf("updateLatestVersionAfterDeletion: failed to list versions in %s: %v", versionsDir, err)
 		return fmt.Errorf("failed to list versions: %v", err)
@@ -1011,6 +1011,7 @@ func (s3a *S3ApiServer) updateLatestVersionAfterDeletion(bucket, object string)
 	var latestVersionId string
 	var latestVersionFileName string
 	var latestVersionEntry *filer_pb.Entry
+	hasDeleteMarkers := false
 
 	for _, entry := range entries {
 		if entry.Extended == nil {
@@ -1027,6 +1028,7 @@ func (s3a *S3ApiServer) updateLatestVersionAfterDeletion(bucket, object string)
 		// Skip delete markers when finding latest content version
 		isDeleteMarkerBytes, _ := entry.Extended[s3_constants.ExtDeleteMarkerKey]
 		if string(isDeleteMarkerBytes) == "true" {
+			hasDeleteMarkers = true
 			continue
 		}
 
@@ -1070,14 +1072,18 @@ func (s3a *S3ApiServer) updateLatestVersionAfterDeletion(bucket, object string)
 		if err != nil {
 			return fmt.Errorf("failed to update .versions directory metadata: %v", err)
 		}
+	} else if hasDeleteMarkers || !isLast {
+		// Delete markers still exist in the .versions directory, or the listing was
+		// truncated so there may be more entries. Either way, keep the directory.
+		glog.V(2).Infof("updateLatestVersionAfterDeletion: no content versions found for %s/%s but .versions directory still has entries (deleteMarkers=%v, isLast=%v), keeping directory",
+			bucket, object, hasDeleteMarkers, isLast)
 	} else {
-		// No versions left - delete the .versions metadata file entirely
-		// This prevents clients from seeing an empty .versions file
-		glog.V(2).Infof("updateLatestVersionAfterDeletion: no versions left for %s/%s, deleting .versions metadata file", bucket, object)
+		// No entries at all - delete the .versions directory entirely
+		glog.V(2).Infof("updateLatestVersionAfterDeletion: no versions left for %s/%s, deleting .versions directory", bucket, object)
 
 		err = s3a.rm(bucketDir, versionsObjectPath, true, false)
 		if err != nil {
-			glog.Warningf("updateLatestVersionAfterDeletion: failed to delete .versions metadata file for %s/%s: %v", bucket, object, err)
+			glog.Warningf("updateLatestVersionAfterDeletion: failed to delete .versions directory for %s/%s: %v", bucket, object, err)
 			// Don't return error - the versions are already deleted, this is just cleanup
 		}
 	}