feat(repos): add topic iterator

Co-Authored-By: Virgil <virgil@lethean.io>

repos.go

@@ -269,6 +269,22 @@ func (s *RepoService) ListTopics(ctx context.Context, owner, repo string) ([]str
 	return out.TopicNames, nil
 }
 
+// IterTopics returns an iterator over the topics assigned to a repository.
+func (s *RepoService) IterTopics(ctx context.Context, owner, repo string) iter.Seq2[string, error] {
+	return func(yield func(string, error) bool) {
+		topics, err := s.ListTopics(ctx, owner, repo)
+		if err != nil {
+			yield("", err)
+			return
+		}
+		for _, topic := range topics {
+			if !yield(topic, nil) {
+				return
+			}
+		}
+	}
+}
+
 // SearchTopics searches topics by keyword.
 func (s *RepoService) SearchTopics(ctx context.Context, query string) ([]types.TopicResponse, error) {
 	return ListAll[types.TopicResponse](ctx, s.client, "/api/v1/topics/search", map[string]string{"q": query})

repos_test.go

@@ -35,6 +35,38 @@ func TestRepoService_ListTopics_Good(t *testing.T) {
 	}
 }
 
+func TestRepoService_IterTopics_Good(t *testing.T) {
+	var requests int
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		requests++
+		if r.Method != http.MethodGet {
+			t.Errorf("expected GET, got %s", r.Method)
+		}
+		if r.URL.Path != "/api/v1/repos/core/go-forge/topics" {
+			t.Errorf("wrong path: %s", r.URL.Path)
+			http.NotFound(w, r)
+			return
+		}
+		json.NewEncoder(w).Encode(types.TopicName{TopicNames: []string{"go", "forge"}})
+	}))
+	defer srv.Close()
+
+	f := NewForge(srv.URL, "tok")
+	var got []string
+	for topic, err := range f.Repos.IterTopics(context.Background(), "core", "go-forge") {
+		if err != nil {
+			t.Fatal(err)
+		}
+		got = append(got, topic)
+	}
+	if requests != 1 {
+		t.Fatalf("expected 1 request, got %d", requests)
+	}
+	if !reflect.DeepEqual(got, []string{"go", "forge"}) {
+		t.Fatalf("got %#v", got)
+	}
+}
+
 func TestRepoService_SearchTopics_Good(t *testing.T) {
 	var requests int
 	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {