fix #1446

dev/result_set_iterator.h

@@ -42,7 +42,8 @@ namespace sqlite_orm::internal {
         using iterator_category = std::input_iterator_tag;
 #endif
         using difference_type = ptrdiff_t;
-        using value_type = column_result_proxy_t<ColResult>;
+        // using value_type = column_result_proxy_t<ColResult>;
+        using value_type = decltype(make_row_extractor<ColResult>(std::declval<db_objects_type>()).extract(nullptr, 0));
 
       public:
         result_set_iterator(const db_objects_type& dbObjects, statement_finalizer stmt) :

include/sqlite_orm/sqlite_orm.h

@@ -16447,7 +16447,8 @@ namespace sqlite_orm::internal {
         using iterator_category = std::input_iterator_tag;
 #endif
         using difference_type = ptrdiff_t;
-        using value_type = column_result_proxy_t<ColResult>;
+        // using value_type = column_result_proxy_t<ColResult>;
+        using value_type = decltype(make_row_extractor<ColResult>(std::declval<db_objects_type>()).extract(nullptr, 0));
 
       public:
         result_set_iterator(const db_objects_type& dbObjects, statement_finalizer stmt) :

tests/unique_cases/issue1446.cpp

@@ -0,0 +1,60 @@
+#include <sqlite_orm/sqlite_orm.h>
+#include <catch2/catch_all.hpp>
+
+#if SQLITE_VERSION_NUMBER >= 3006019
+using namespace sqlite_orm;
+
+#ifdef SQLITE_ORM_OPTIONAL_SUPPORTED
+#ifdef SQLITE_ORM_DEFAULT_COMPARISONS_SUPPORTED
+
+TEST_CASE("issue1446") {
+    struct Employee {
+        int m_empno;
+        std::string m_ename;
+        std::string m_job;
+        std::optional<int> m_mgr;
+        std::string m_hiredate;
+        double m_salary;
+        std::optional<double> m_commission;
+        int m_depno;
+    };
+
+    struct Department {
+        int m_deptno;
+        std::string m_deptname;
+        std::string m_loc;
+    };
+
+    using namespace sqlite_orm;
+
+    auto storage = make_storage("",
+                                make_table("Emp",
+                                           make_column("empno", &Employee::m_empno, primary_key().autoincrement()),
+                                           make_column("ename", &Employee::m_ename),
+                                           make_column("job", &Employee::m_job),
+                                           make_column("mgr", &Employee::m_mgr),
+                                           make_column("hiredate", &Employee::m_hiredate),
+                                           make_column("salary", &Employee::m_salary),
+                                           make_column("comm", &Employee::m_commission),
+                                           make_column("depno", &Employee::m_depno),
+                                           foreign_key(&Employee::m_depno).references(&Department::m_deptno)),
+                                make_table("Dept",
+                                           make_column("deptno", &Department::m_deptno, primary_key().autoincrement()),
+                                           make_column("deptname", &Department::m_deptname),
+                                           make_column("loc", &Department::m_loc, null())));
+    storage.sync_schema(true);
+    storage.insert(Department{10, "Accounts", "New York"});
+    storage.insert(Employee{1, "Paul", "Salesman", 2, "2002-02-12", 20000.0, 0.0, 1});
+    storage.insert(Employee{2, "Allen", "Salesman", 2, "2002-02-12", 20000.0, 0.0, 1});
+    for (auto&& [obj, obj2, col]:
+         storage.iterate(select(columns(object<Employee>(true), object<Department>(true), &Department::m_deptno),
+                                from<Employee>(),
+                                join<Department>(on(c(&Employee::m_depno) == c(&Department::m_deptno)))))) {
+        STATIC_REQUIRE(std::is_same_v<decltype(obj), Employee>);
+        STATIC_REQUIRE(std::is_same_v<decltype(obj2), Department>);
+        STATIC_REQUIRE(std::is_same_v<decltype(col), int>);
+    }
+}
+#endif
+#endif
+#endif