use generic version of btree (#3404)

internal/sets/sorted.go

@@ -2,51 +2,47 @@ package sets
 
 import "github.com/google/btree"
 
-type stringItem string
-
-func (item stringItem) Less(than btree.Item) bool {
-	return item < than.(stringItem)
-}
+func lessFn(a, b string) bool { return a < b }
 
 // A SortedString is a set of strings with sorted iteration.
 type SortedString struct {
-	b *btree.BTree
+	b *btree.BTreeG[string]
 }
 
 // NewSortedString creates a new sorted string set.
 func NewSortedString() *SortedString {
 	return &SortedString{
-		b: btree.New(8),
+		b: btree.NewG[string](8, lessFn),
 	}
 }
 
 // Add adds a string to the set.
 func (s *SortedString) Add(elements ...string) {
 	for _, element := range elements {
-		s.b.ReplaceOrInsert(stringItem(element))
+		s.b.ReplaceOrInsert(element)
 	}
 }
 
 // Clear clears the set.
 func (s *SortedString) Clear() {
-	s.b = btree.New(8)
+	s.b = btree.NewG[string](8, lessFn)
 }
 
 // Delete deletes an element from the set.
 func (s *SortedString) Delete(element string) {
-	s.b.Delete(stringItem(element))
+	s.b.Delete(element)
 }
 
 // ForEach iterates over the set in ascending order.
 func (s *SortedString) ForEach(callback func(element string) bool) {
-	s.b.Ascend(func(i btree.Item) bool {
-		return callback(string(i.(stringItem)))
+	s.b.Ascend(func(item string) bool {
+		return callback(item)
 	})
 }
 
 // Has returns true if the elment is in the set.
 func (s *SortedString) Has(element string) bool {
-	return s.b.Has(stringItem(element))
+	return s.b.Has(element)
 }
 
 // Size returns the size of the set.
@@ -57,8 +53,8 @@ func (s *SortedString) Size() int {
 // ToSlice returns a slice of all the elements in the set.
 func (s *SortedString) ToSlice() []string {
 	arr := make([]string, 0, s.Size())
-	s.b.Ascend(func(i btree.Item) bool {
-		arr = append(arr, string(i.(stringItem)))
+	s.b.Ascend(func(item string) bool {
+		arr = append(arr, item)
 		return true
 	})
 	return arr