Do not notify when updated bookmarks are empty

Also get rid of unnecessary bookmark copy

Author: fbiville

neo4j/bookmarks.go

@@ -77,6 +77,9 @@ type bookmarkManager struct {
 }
 
 func (b *bookmarkManager) UpdateBookmarks(database string, previousBookmarks, newBookmarks Bookmarks) {
+	if len(newBookmarks) == 0 {
+		return
+	}
 	var bookmarksToNotify Bookmarks
 	storedNewBookmarks := collection.NewSet(newBookmarks)
 	if rawCurrentBookmarks, loaded := b.bookmarks.LoadOrStore(database, storedNewBookmarks); !loaded {
@@ -98,7 +101,7 @@ func (b *bookmarkManager) GetAllBookmarks() Bookmarks {
 		allBookmarks.AddAll(b.supplier.GetAllBookmarks())
 	}
 	b.bookmarks.Range(func(db, rawBookmarks any) bool {
-		bookmarks := rawBookmarks.(collection.Set[string]).Copy()
+		bookmarks := rawBookmarks.(collection.Set[string])
 		allBookmarks.Union(bookmarks)
 		return true
 	})

neo4j/bookmarks_test.go

@@ -152,6 +152,21 @@ func TestBookmarkManager(outer *testing.T) {
 		}
 	})
 
+	outer.Run("does not notify updated bookmarks when empty", func(t *testing.T) {
+		initialBookmarks := []string{"a", "b"}
+		bookmarkManager := neo4j.NewBookmarkManager(neo4j.BookmarkManagerConfig{
+			InitialBookmarks: map[string]neo4j.Bookmarks{"db1": initialBookmarks},
+			BookmarkUpdateNotifier: func(db string, bookmarks neo4j.Bookmarks) {
+				t.Error("I must not be called")
+			},
+		})
+
+		bookmarkManager.UpdateBookmarks("db1", initialBookmarks, nil)
+
+		actualBookmarks := bookmarkManager.GetBookmarks("db1")
+		AssertEqualsInAnyOrder(t, actualBookmarks, initialBookmarks)
+	})
+
 	outer.Run("notifies updated bookmarks for existing DB without bookmarks", func(t *testing.T) {
 		notifyHookCalled := false
 		expectedBookmarks := []string{"a", "d"}

neo4j/internal/collection/set.go

@@ -59,7 +59,7 @@ func (set Set[T]) Values() []T {
 	}
 	result := make([]T, len(set), len(set))
 	i := 0
-	for value, _ := range set {
+	for value := range set {
 		result[i] = value
 		i++
 	}