ilm: Expect objects with only free versions when scanning (minio#21112)

Author: krisis

cmd/data-scanner.go

@@ -1036,6 +1036,9 @@ type actionsAccountingFn func(oi ObjectInfo, sz, actualSz int64, sizeS *sizeSumm
 // The metadata will be compared to consensus on the object layer before any changes are applied.
 // If no metadata is supplied, -1 is returned if no action is taken.
 func (i *scannerItem) applyActions(ctx context.Context, objAPI ObjectLayer, objInfos []ObjectInfo, lr lock.Retention, sizeS *sizeSummary, fn actionsAccountingFn) {
+	if len(objInfos) == 0 {
+		return
+	}
 	healActions := func(oi ObjectInfo, actualSz int64) int64 {
 		size := actualSz
 		if i.heal.enabled {

cmd/data-scanner_test.go

@@ -245,6 +245,12 @@ func TestApplyNewerNoncurrentVersionsLimit(t *testing.T) {
 			wants:       nil,
 			wantExpired: []ObjectToDelete{{ObjectV: ObjectV{ObjectName: obj, VersionID: allVersExpObjInfos[0].VersionID}}},
 		},
+		{
+			// When no versions are present, in practice this could be an object with only free versions
+			objInfos:    nil,
+			wants:       nil,
+			wantExpired: nil,
+		},
 	}
 	for i, test := range tests {
 		t.Run(fmt.Sprintf("TestApplyNewerNoncurrentVersionsLimit-%d", i), func(t *testing.T) {

internal/bucket/lifecycle/evaluator.go

@@ -146,6 +146,9 @@ loop:
 
 // Eval will return a lifecycle event for each object in objs
 func (e *Evaluator) Eval(objs []ObjectOpts) ([]Event, error) {
+	if len(objs) == 0 {
+		return nil, nil
+	}
 	if len(objs) != objs[0].NumVersions {
 		return nil, fmt.Errorf("number of versions mismatch, expected %d, got %d", objs[0].NumVersions, len(objs))
 	}

internal/bucket/lifecycle/evaluator_test.go

@@ -144,6 +144,12 @@ func TestNewerNoncurrentVersions(t *testing.T) {
 			t.Fatalf("test-%d: got %v, want %v", i+1, gotEvents[i], wantEvents[i])
 		}
 	}
+
+	// Test with zero versions
+	events, err := evaluator.Eval(nil)
+	if len(events) != 0 || err != nil {
+		t.Fatal("expected no events nor error")
+	}
 }
 
 func TestEmptyEvaluator(t *testing.T) {