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

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) {