return ErrNoCookie to ensure that errors arent hidden

cookie.go

@@ -15,6 +15,9 @@ const (
 	CookieTag = "cookie"
 )
 
+// ErrNoCookie is returned when a cookie is not found.
+var ErrNoCookie = http.ErrNoCookie
+
 // UnsupportedTypeError is returned when a field type is not supported by PopulateFromCookies.
 type UnsupportedTypeError struct {
 	Type reflect.Type
@@ -80,7 +83,7 @@ func PopulateFromCookies(r *http.Request, dest interface{}) error {
 		cookie, err := Get(r, tag)
 		if err != nil {
 			if errors.Is(err, http.ErrNoCookie) {
-				continue // Skip if the cookie is not found
+				return ErrNoCookie
 			}
 			return err
 		}

cookie_test.go

@@ -316,12 +316,8 @@ func TestPopulateFromCookies_NotFound(t *testing.T) {
 
 	dest := &MyStruct{}
 	err := PopulateFromCookies(r, dest)
-	if err != nil {
-		t.Fatalf("Unexpected error: %v", err)
-	}
-
-	if dest.StringField != "" {
-		t.Errorf("Expected StringField to be empty, got %s", dest.StringField)
+	if err != ErrNoCookie {
+		t.Errorf("Expected error ErrNoCookie, got %v", err)
 	}
 }