sets: convert set types to generics (#3519)

* sets: convert set types to generics

* sets: use internal sets package

internal/sets/sorted.go

@@ -1,59 +1,65 @@
 package sets
 
-import "github.com/google/btree"
+import (
+	"github.com/google/btree"
+	"golang.org/x/exp/constraints"
+)
 
-func lessFn(a, b string) bool { return a < b }
-
-// A SortedString is a set of strings with sorted iteration.
-type SortedString struct {
-	b *btree.BTreeG[string]
+// A Sorted is a set with sorted iteration.
+type Sorted[T any] struct {
+	b    *btree.BTreeG[T]
+	less func(a, b T) bool
 }
 
-// NewSortedString creates a new sorted string set.
-func NewSortedString() *SortedString {
-	return &SortedString{
-		b: btree.NewG[string](8, lessFn),
+// NewSorted creates a new sorted string set.
+func NewSorted[T constraints.Ordered]() *Sorted[T] {
+	less := func(a, b T) bool {
+		return a < b
+	}
+	return &Sorted[T]{
+		b:    btree.NewG(8, less),
+		less: less,
 	}
 }
 
 // Add adds a string to the set.
-func (s *SortedString) Add(elements ...string) {
+func (s *Sorted[T]) Add(elements ...T) {
 	for _, element := range elements {
 		s.b.ReplaceOrInsert(element)
 	}
 }
 
 // Clear clears the set.
-func (s *SortedString) Clear() {
-	s.b = btree.NewG[string](8, lessFn)
+func (s *Sorted[T]) Clear() {
+	s.b = btree.NewG(8, s.less)
 }
 
 // Delete deletes an element from the set.
-func (s *SortedString) Delete(element string) {
+func (s *Sorted[T]) Delete(element T) {
 	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(item string) bool {
+func (s *Sorted[T]) ForEach(callback func(element T) bool) {
+	s.b.Ascend(func(item T) bool {
 		return callback(item)
 	})
 }
 
 // Has returns true if the elment is in the set.
-func (s *SortedString) Has(element string) bool {
+func (s *Sorted[T]) Has(element T) bool {
 	return s.b.Has(element)
 }
 
 // Size returns the size of the set.
-func (s *SortedString) Size() int {
+func (s *Sorted[T]) Size() int {
 	return s.b.Len()
 }
 
 // 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(item string) bool {
+func (s *Sorted[T]) ToSlice() []T {
+	arr := make([]T, 0, s.Size())
+	s.b.Ascend(func(item T) bool {
 		arr = append(arr, item)
 		return true
 	})