Don't tier directory objects (minio#19891)

Directory objects are used by applications that simulate the folder
structure of an on-disk filesystem. These are zero-byte objects with names
ending with '/'. They are only used to check whether a 'folder' exists in
the namespace.

Author: krisis

cmd/bucket-lifecycle.go

@@ -583,6 +583,10 @@ func enqueueTransitionImmediate(obj ObjectInfo, src lcEventSrc) {
 	if lc, err := globalLifecycleSys.Get(obj.Bucket); err == nil {
 		switch event := lc.Eval(obj.ToLifecycleOpts()); event.Action {
 		case lifecycle.TransitionAction, lifecycle.TransitionVersionAction:
+			if obj.DeleteMarker || obj.IsDir {
+				// nothing to transition
+				return
+			}
 			globalTransitionState.queueTransitionTask(obj, event, src)
 		}
 	}

cmd/data-scanner.go

@@ -1233,7 +1233,7 @@ func evalActionFromLifecycle(ctx context.Context, lc lifecycle.Lifecycle, lr loc
 }
 
 func applyTransitionRule(event lifecycle.Event, src lcEventSrc, obj ObjectInfo) bool {
-	if obj.DeleteMarker {
+	if obj.DeleteMarker || obj.IsDir {
 		return false
 	}
 	globalTransitionState.queueTransitionTask(obj, event, src)