set: Allow nil/expired items

Fixes #397

set/set.go

@@ -12,9 +12,6 @@ var ErrCollision = errors.New("key already exists")
 // Returned when a requested item does not exist in the set.
 var ErrMissing = errors.New("item does not exist")
 
-// Returned when a nil item is added. Nil values are considered expired and invalid.
-var ErrNil = errors.New("item value must not be nil")
-
 // ZeroValue can be used when we only care about the key, not about the value.
 var ZeroValue = struct{}{}
 
@@ -100,7 +97,7 @@ func (s *Set) Get(key string) (Item, error) {
 func (s *Set) cleanup(key string) {
 	s.Lock()
 	item, ok := s.lookup[key]
-	if ok && item == nil {
+	if ok && item.Value() == nil {
 		delete(s.lookup, key)
 	}
 	s.Unlock()
@@ -108,9 +105,6 @@ func (s *Set) cleanup(key string) {
 
 // Add item to this set if it does not exist already.
 func (s *Set) Add(item Item) error {
-	if item.Value() == nil {
-		return ErrNil
-	}
 	key := s.normalize(item.Key())
 
 	s.Lock()
@@ -127,9 +121,6 @@ func (s *Set) Add(item Item) error {
 
 // Set item to this set, even if it already exists.
 func (s *Set) Set(item Item) error {
-	if item.Value() == nil {
-		return ErrNil
-	}
 	key := s.normalize(item.Key())
 
 	s.Lock()
@@ -156,9 +147,6 @@ func (s *Set) Remove(key string) error {
 // Replace oldKey with a new item, which might be a new key.
 // Can be used to rename items.
 func (s *Set) Replace(oldKey string, item Item) error {
-	if item.Value() == nil {
-		return ErrNil
-	}
 	newKey := s.normalize(item.Key())
 	oldKey = s.normalize(oldKey)
 

set/set_test.go

@@ -21,14 +21,23 @@ func TestSetExpiring(t *testing.T) {
 		t.Error("not len 1 after set")
 	}
 
-	item := &ExpiringItem{nil, time.Now().Add(-time.Nanosecond * 1)}
+	item := Expire(StringItem("asdf"), -time.Nanosecond).(*ExpiringItem)
 	if !item.Expired() {
 		t.Errorf("ExpiringItem a nanosec ago is not expiring")
 	}
+	if err := s.Add(item); err != nil {
+		t.Error("Error adding expired item to set: ", err)
+	}
+	if s.In("asdf") {
+		t.Error("Expired item in set")
+	}
+	if s.Len() != 1 {
+		t.Error("not len 1 after expired item")
+	}
 
 	item = &ExpiringItem{nil, time.Now().Add(time.Minute * 5)}
 	if item.Expired() {
-		t.Errorf("ExpiringItem in 2 minutes is expiring now")
+		t.Errorf("ExpiringItem in 5 minutes is expiring now")
 	}
 
 	item = Expire(StringItem("bar"), time.Minute*5).(*ExpiringItem)
@@ -42,11 +51,13 @@ func TestSetExpiring(t *testing.T) {
 	if err := s.Add(item); err != nil {
 		t.Fatalf("failed to add item: %s", err)
 	}
-	_, ok := s.lookup["bar"]
+	itemInLookup, ok := s.lookup["bar"]
 	if !ok {
-		t.Fatalf("expired bar added to lookup")
+		t.Fatalf("bar not present in lookup even though it's not expired")
+	}
+	if itemInLookup != item {
+		t.Fatalf("present item %#v != %#v original item", itemInLookup, item)
 	}
-	s.lookup["bar"] = item
 
 	if !s.In("bar") {
 		t.Errorf("not matched after timed set")