ilm: Handle DeleteAllVersions action differently for DEL markers (#19481)

i.e., this rule element doesn't apply to DEL markers.

This is a breaking change to how ExpiredObejctDeleteAllVersions
functions today. This is necessary to avoid the following highly probable
footgun scenario in the future.

Scenario:
The user uses tags-based filtering to select an object's time to live(TTL). 
The application sometimes deletes objects, too, making its latest
version a DEL marker. The previous implementation skipped tag-based filters
if the newest version was DEL marker, voiding the tag-based TTL. The user is
surprised to find objects that have expired sooner than expected.

* Add DelMarkerExpiration action

This ILM action removes all versions of an object if its
the latest version is a DEL marker.

```xml
<DelMarkerObjectExpiration>
    <Days> 10 </Days>
</DelMarkerObjectExpiration>
```

1. Applies only to objects whose,
  • The latest version is a DEL marker.
  • satisfies the number of days criteria
2. Deletes all versions of this object
3. Associated rule can't have tag-based filtering

Includes,
- New bucket event type for deletion due to DelMarkerExpiration

cmd/data-scanner.go

@@ -993,7 +993,7 @@ func (i *scannerItem) applyLifecycle(ctx context.Context, o ObjectLayer, oi Obje
 	// This can happen when,
 	// - ExpireObjectAllVersions flag is enabled
 	// - NoncurrentVersionExpiration is applicable
-	case lifecycle.DeleteVersionAction, lifecycle.DeleteAllVersionsAction:
+	case lifecycle.DeleteVersionAction, lifecycle.DeleteAllVersionsAction, lifecycle.DelMarkerDeleteAllVersionsAction:
 		size = 0
 	case lifecycle.DeleteAction:
 		// On a non-versioned bucket, DeleteObject removes the only version permanently.
@@ -1162,7 +1162,7 @@ func (i *scannerItem) applyActions(ctx context.Context, o ObjectLayer, oi Object
 
 	// Note: objDeleted is true if and only if action ==
 	// lifecycle.DeleteAllVersionsAction
-	if action == lifecycle.DeleteAllVersionsAction {
+	if action.DeleteAll() {
 		return true, 0
 	}
 
@@ -1292,7 +1292,7 @@ func applyExpiryOnNonTransitionedObjects(ctx context.Context, objLayer ObjectLay
 
 		if lcEvent.Action != lifecycle.NoneAction {
 			numVersions := uint64(1)
-			if lcEvent.Action == lifecycle.DeleteAllVersionsAction {
+			if lcEvent.Action.DeleteAll() {
 				numVersions = uint64(obj.NumVersions)
 			}
 			globalScannerMetrics.timeILM(lcEvent.Action)(numVersions)
@@ -1320,8 +1320,11 @@ func applyExpiryOnNonTransitionedObjects(ctx context.Context, objLayer ObjectLay
 	if obj.DeleteMarker {
 		eventName = event.ObjectRemovedDeleteMarkerCreated
 	}
-	if lcEvent.Action.DeleteAll() {
+	switch lcEvent.Action {
+	case lifecycle.DeleteAllVersionsAction:
 		eventName = event.ObjectRemovedDeleteAllVersions
+	case lifecycle.DelMarkerDeleteAllVersionsAction:
+		eventName = event.ILMDelMarkerExpirationDelete
 	}
 	// Notify object deleted event.
 	sendEvent(eventArgs{
@@ -1346,7 +1349,7 @@ func applyLifecycleAction(event lifecycle.Event, src lcEventSrc, obj ObjectInfo)
 	switch action := event.Action; action {
 	case lifecycle.DeleteVersionAction, lifecycle.DeleteAction,
 		lifecycle.DeleteRestoredAction, lifecycle.DeleteRestoredVersionAction,
-		lifecycle.DeleteAllVersionsAction:
+		lifecycle.DeleteAllVersionsAction, lifecycle.DelMarkerDeleteAllVersionsAction:
 		success = applyExpiryRule(event, src, obj)
 	case lifecycle.TransitionAction, lifecycle.TransitionVersionAction:
 		success = applyTransitionRule(event, src, obj)

cmd/erasure-object.go

@@ -1886,12 +1886,13 @@ func (er erasureObjects) DeleteObject(ctx context.Context, bucket, object string
 			// based on the latest objectInfo and see if the object still
 			// qualifies for deletion.
 			if gerr == nil {
-				evt := evalActionFromLifecycle(ctx, *lc, rcfg, replcfg, goi)
 				var isErr bool
+				evt := evalActionFromLifecycle(ctx, *lc, rcfg, replcfg, goi)
 				switch evt.Action {
-				case lifecycle.NoneAction:
-					isErr = true
-				case lifecycle.TransitionAction, lifecycle.TransitionVersionAction:
+				case lifecycle.DeleteAllVersionsAction, lifecycle.DelMarkerDeleteAllVersionsAction:
+					// opts.DeletePrefix is used only in the above lifecycle Expiration actions.
+				default:
+					// object has been modified since lifecycle action was previously evaluated
 					isErr = true
 				}
 				if isErr {