emplace into optional to be able to visit variant containers containi…

[Urfoex]

…ng const fields

Issue with proposed solution: #228

[liuzicheng1987]

LGTM, other than that one of your tests fails. If you can fix that, I will merge.

[Urfoex]

LGTM, other than that one of your tests fails. If you can fix that, I will merge.

@liuzicheng1987 👍

Just tried with devcontainer, Debian Bookworm, Clang 16, and it passed 🤔
Have to investigate more…
Edit: Fails locally with clang 19, succeeds with 18

-- Running vcpkg install - done
-- The CXX compiler identification is Clang 16.0.6
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/clang++-16 - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD
-- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success
-- Found Threads: TRUE  
-- The C compiler identification is Clang 16.0.6
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/clang-16 - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Configuring done
-- Generating done
-- Build files have been written to: /workspaces/reflect-cpp/devc_c16
vscode ➜ /workspaces/reflect-cpp (feature/visit-variant-with-const-field) $ cmake --build devc_c16/
[0/2] Re-checking globbed directories...
[492/498] Building CXX object benchmarks/json/CMakeFiles/reflect-cpp-json-benchmarks.dir/canada.cpp.o
/workspaces/reflect-cpp/benchmarks/json/canada.cpp:258:39: warning: unused function 'read_using_simdjson' [-Wunused-function]
static rfl::Result<FeatureCollection> read_using_simdjson(
                                      ^
1 warning generated.
[498/498] Linking CXX executable benchmarks/all/reflect-cpp-all-format-benchmarks
vscode ➜ /workspaces/reflect-cpp (feature/visit-variant-with-const-field) $ 

vscode ➜ /workspaces/reflect-cpp (feature/visit-variant-with-const-field) $ ./devc_c16/tests/json/reflect-cpp-json-tests 
Running main() from /workspaces/reflect-cpp/devc_c16/vcpkg_installed/x64-linux/src/gtest_main.cc
[==========] Running 141 tests from 1 test suite.
[----------] Global test environment set-up.
[----------] 141 tests from json
[ RUN      ] json.test_add_struct_name
[       OK ] json.test_add_struct_name (0 ms)
[ RUN      ] json.test_all_of
[       OK ] json.test_all_of (0 ms)
[ RUN      ] json.test_alphanumeric_map
[       OK ] json.test_alphanumeric_map (0 ms)
[ RUN      ] json.test_alphanumeric_unordered_map
[       OK ] json.test_alphanumeric_unordered_map (0 ms)
[ RUN      ] json.test_and_then
[       OK ] json.test_and_then (0 ms)
[ RUN      ] json.test_anonymous_fields
[       OK ] json.test_anonymous_fields (0 ms)
[ RUN      ] json.test_any_of
[       OK ] json.test_any_of (0 ms)
[ RUN      ] json.test_apply
[       OK ] json.test_apply (0 ms)
[ RUN      ] json.test_array
[       OK ] json.test_array (0 ms)
[ RUN      ] json.test_array2
[       OK ] json.test_array2 (0 ms)
[ RUN      ] json.test_as
[       OK ] json.test_as (0 ms)
[ RUN      ] json.test_as2
[       OK ] json.test_as2 (0 ms)
[ RUN      ] json.test_as_flatten
[       OK ] json.test_as_flatten (0 ms)
[ RUN      ] json.test_binary
[       OK ] json.test_binary (0 ms)
[ RUN      ] json.test_box
[       OK ] json.test_box (0 ms)
[ RUN      ] json.test_box2
[       OK ] json.test_box2 (0 ms)
[ RUN      ] json.test_combined_processors
[       OK ] json.test_combined_processors (0 ms)
[ RUN      ] json.test_const_fields
[       OK ] json.test_const_fields (0 ms)
[ RUN      ] json.test_custom_class1
[       OK ] json.test_custom_class1 (0 ms)
[ RUN      ] json.test_custom_class2
[       OK ] json.test_custom_class2 (0 ms)
[ RUN      ] json.test_custom_class3
[       OK ] json.test_custom_class3 (0 ms)
[ RUN      ] json.test_custom_class4
[       OK ] json.test_custom_class4 (0 ms)
[ RUN      ] json.test_custom_constructor
[       OK ] json.test_custom_constructor (0 ms)
[ RUN      ] json.test_deep_nested
[       OK ] json.test_deep_nested (0 ms)
[ RUN      ] json.test_default_if_missing
[       OK ] json.test_default_if_missing (0 ms)
[ RUN      ] json.test_default_if_missing_no_field_names
[       OK ] json.test_default_if_missing_no_field_names (0 ms)
[ RUN      ] json.test_default_values
[       OK ] json.test_default_values (0 ms)
[ RUN      ] json.test_deque
[       OK ] json.test_deque (0 ms)
[ RUN      ] json.test_email
[       OK ] json.test_email (0 ms)
[ RUN      ] json.test_empty_object
[       OK ] json.test_empty_object (0 ms)
[ RUN      ] json.test_enum1
[       OK ] json.test_enum1 (0 ms)
[ RUN      ] json.test_enum2
[       OK ] json.test_enum2 (0 ms)
[ RUN      ] json.test_enum3
[       OK ] json.test_enum3 (0 ms)
[ RUN      ] json.test_enum4
[       OK ] json.test_enum4 (0 ms)
[ RUN      ] json.test_enum5
[       OK ] json.test_enum5 (0 ms)
[ RUN      ] json.test_enum6
[       OK ] json.test_enum6 (0 ms)
[ RUN      ] json.test_enum7
[       OK ] json.test_enum7 (0 ms)
[ RUN      ] json.test_error_messages
[       OK ] json.test_error_messages (0 ms)
[ RUN      ] json.test_extra_fields
[       OK ] json.test_extra_fields (0 ms)
[ RUN      ] json.test_extra_fields_with_no_extra_fields
[       OK ] json.test_extra_fields_with_no_extra_fields (0 ms)
[ RUN      ] json.test_field_variant
[       OK ] json.test_field_variant (0 ms)
[ RUN      ] json.test_field_variant_std
[       OK ] json.test_field_variant_std (0 ms)
[ RUN      ] json.test_filepath
[       OK ] json.test_filepath (0 ms)
[ RUN      ] json.test_flag_enum1
[       OK ] json.test_flag_enum1 (0 ms)
[ RUN      ] json.test_flag_enum2
[       OK ] json.test_flag_enum2 (0 ms)
[ RUN      ] json.test_flag_enum_with_int
[       OK ] json.test_flag_enum_with_int (0 ms)
[ RUN      ] json.test_flatten
[       OK ] json.test_flatten (0 ms)
[ RUN      ] json.test_flatten_anonymous
[       OK ] json.test_flatten_anonymous (0 ms)
[ RUN      ] json.test_forward_list
[       OK ] json.test_forward_list (0 ms)
[ RUN      ] json.test_generic
[       OK ] json.test_generic (0 ms)
[ RUN      ] json.test_hex
[       OK ] json.test_hex (0 ms)
[ RUN      ] json.test_inside_function
[       OK ] json.test_inside_function (0 ms)
[ RUN      ] json.test_integers
[       OK ] json.test_integers (0 ms)
[ RUN      ] json.test_json_schema
[       OK ] json.test_json_schema (0 ms)
[ RUN      ] json.test_json_schema2
[       OK ] json.test_json_schema2 (0 ms)
[ RUN      ] json.test_json_schema3
[       OK ] json.test_json_schema3 (0 ms)
[ RUN      ] json.test_json_schema_sized_vector_min1_max2
[       OK ] json.test_json_schema_sized_vector_min1_max2 (0 ms)
[ RUN      ] json.test_json_schema_sized_set_min2_max3
[       OK ] json.test_json_schema_sized_set_min2_max3 (0 ms)
[ RUN      ] json.test_json_schema_sized_string_min4_max6
[       OK ] json.test_json_schema_sized_string_min4_max6 (0 ms)
[ RUN      ] json.test_json_schema_sized_vector_anyof_eq3_eq7
[       OK ] json.test_json_schema_sized_vector_anyof_eq3_eq7 (0 ms)
[ RUN      ] json.test_json_schema_sized_set_anyof_eq15_eq16
[       OK ] json.test_json_schema_sized_set_anyof_eq15_eq16 (0 ms)
[ RUN      ] json.test_json_schema_sized_string_anyof_eq1_eq10
[       OK ] json.test_json_schema_sized_string_anyof_eq1_eq10 (0 ms)
[ RUN      ] json.test_leak
[       OK ] json.test_leak (0 ms)
[ RUN      ] json.test_leak_arr
[       OK ] json.test_leak_arr (0 ms)
[ RUN      ] json.test_leak_rfl_tup
[       OK ] json.test_leak_rfl_tup (0 ms)
[ RUN      ] json.test_leak_tup
[       OK ] json.test_leak_tup (0 ms)
[ RUN      ] json.test_list
[       OK ] json.test_list (0 ms)
[ RUN      ] json.test_literal
[       OK ] json.test_literal (0 ms)
[ RUN      ] json.test_literal_map
[       OK ] json.test_literal_map (0 ms)
[ RUN      ] json.test_literal_unordered_map
[       OK ] json.test_literal_unordered_map (0 ms)
[ RUN      ] json.test_many_fields
[       OK ] json.test_many_fields (0 ms)
[ RUN      ] json.test_map
[       OK ] json.test_map (0 ms)
[ RUN      ] json.test_map_with_key_validation
[       OK ] json.test_map_with_key_validation (0 ms)
[ RUN      ] json.test_meta_fields
[       OK ] json.test_meta_fields (0 ms)
[ RUN      ] json.test_monster_example
[       OK ] json.test_monster_example (0 ms)
[ RUN      ] json.test_move_replace
[       OK ] json.test_move_replace (0 ms)
[ RUN      ] json.test_multimap
[       OK ] json.test_multimap (0 ms)
[ RUN      ] json.test_multiset
[       OK ] json.test_multiset (0 ms)
[ RUN      ] json.test_no_extra_fields
[       OK ] json.test_no_extra_fields (0 ms)
[ RUN      ] json.test_no_extra_fields_with_default
[       OK ] json.test_no_extra_fields_with_default (0 ms)
[ RUN      ] json.test_no_optionals
[       OK ] json.test_no_optionals (0 ms)
[ RUN      ] json.test_object
[       OK ] json.test_object (0 ms)
[ RUN      ] json.test_oct
[       OK ] json.test_oct (0 ms)
[ RUN      ] json.test_one_of
[       OK ] json.test_one_of (0 ms)
[ RUN      ] json.test_optional_fields
[       OK ] json.test_optional_fields (0 ms)
[ RUN      ] json.test_readme_example
[       OK ] json.test_readme_example (0 ms)
[ RUN      ] json.test_ref
[       OK ] json.test_ref (0 ms)
[ RUN      ] json.test_reflector
[       OK ] json.test_reflector (0 ms)
[ RUN      ] json.test_reflector_read
[       OK ] json.test_reflector_read (0 ms)
[ RUN      ] json.test_reflector_write
[       OK ] json.test_reflector_write (0 ms)
[ RUN      ] json.test_replace
[       OK ] json.test_replace (0 ms)
[ RUN      ] json.test_replace2
[       OK ] json.test_replace2 (0 ms)
[ RUN      ] json.test_replace_flatten
[       OK ] json.test_replace_flatten (0 ms)
[ RUN      ] json.test_replace_flatten2
[       OK ] json.test_replace_flatten2 (0 ms)
[ RUN      ] json.test_replace_with_other_struct
[       OK ] json.test_replace_with_other_struct (0 ms)
[ RUN      ] json.test_replace_with_other_struct2
[       OK ] json.test_replace_with_other_struct2 (0 ms)
[ RUN      ] json.test_result
[       OK ] json.test_result (0 ms)
[ RUN      ] json.test_rfl_tuple
[       OK ] json.test_rfl_tuple (0 ms)
[ RUN      ] json.test_rfl_variant
[       OK ] json.test_rfl_variant (0 ms)
[ RUN      ] json.test_rfl_variant_emplace
[       OK ] json.test_rfl_variant_emplace (0 ms)
[ RUN      ] json.test_rfl_variant_get_if
[       OK ] json.test_rfl_variant_get_if (0 ms)
[ RUN      ] json.test_rfl_variant_holds_alternative
[       OK ] json.test_rfl_variant_holds_alternative (0 ms)
[ RUN      ] json.test_rfl_variant_swap
[       OK ] json.test_rfl_variant_swap (0 ms)
[ RUN      ] json.test_rfl_variant_visit
[       OK ] json.test_rfl_variant_visit (0 ms)
[ RUN      ] json.test_rfl_variant_visit
[       OK ] json.test_rfl_variant_visit (0 ms)
[ RUN      ] json.test_rfl_variant
[       OK ] json.test_rfl_variant (0 ms)
[ RUN      ] json.test_rfl_variant_visit_move_only
[       OK ] json.test_rfl_variant_visit_move_only (0 ms)
[ RUN      ] json.test_rfl_variant_visit_return_move_only
[       OK ] json.test_rfl_variant_visit_return_move_only (0 ms)
[ RUN      ] json.test_save_load
[       OK ] json.test_save_load (0 ms)
[ RUN      ] json.test_set
[       OK ] json.test_set (0 ms)
[ RUN      ] json.test_shared_ptr
[       OK ] json.test_shared_ptr (0 ms)
[ RUN      ] json.test_size
[       OK ] json.test_size (0 ms)
[ RUN      ] json.test_skip
[       OK ] json.test_skip (0 ms)
[ RUN      ] json.test_snake_case_to_camel_case
[       OK ] json.test_snake_case_to_camel_case (0 ms)
[ RUN      ] json.test_snake_case_to_camel_case_rename
[       OK ] json.test_snake_case_to_camel_case_rename (0 ms)
[ RUN      ] json.test_snake_case_to_pascal_case
[       OK ] json.test_snake_case_to_pascal_case (0 ms)
[ RUN      ] json.test_snake_case_to_pascal_case_rename
[       OK ] json.test_snake_case_to_pascal_case_rename (0 ms)
[ RUN      ] json.test_std_ref
[       OK ] json.test_std_ref (0 ms)
[ RUN      ] json.test_string_map
[       OK ] json.test_string_map (0 ms)
[ RUN      ] json.test_string_unordered_map
[       OK ] json.test_string_unordered_map (0 ms)
[ RUN      ] json.test_string_view
[       OK ] json.test_string_view (0 ms)
[ RUN      ] json.test_strip_field_names
[       OK ] json.test_strip_field_names (0 ms)
[ RUN      ] json.test_tagged_union
[       OK ] json.test_tagged_union (0 ms)
[ RUN      ] json.test_tagged_union2
[       OK ] json.test_tagged_union2 (0 ms)
[ RUN      ] json.test_tagged_union3
[       OK ] json.test_tagged_union3 (0 ms)
[ RUN      ] json.test_tagged_union4
[       OK ] json.test_tagged_union4 (0 ms)
[ RUN      ] json.test_template
[       OK ] json.test_template (0 ms)
[ RUN      ] json.test_timestamp
[       OK ] json.test_timestamp (0 ms)
[ RUN      ] json.test_transform
[       OK ] json.test_transform (0 ms)
[ RUN      ] json.test_tuple
[       OK ] json.test_tuple (0 ms)
[ RUN      ] json.test_underlying_enums
[       OK ] json.test_underlying_enums (0 ms)
[ RUN      ] json.test_unique_ptr
[       OK ] json.test_unique_ptr (0 ms)
[ RUN      ] json.test_unique_ptr2
[       OK ] json.test_unique_ptr2 (0 ms)
[ RUN      ] json.test_unnamed_namespace
[       OK ] json.test_unnamed_namespace (0 ms)
[ RUN      ] json.test_unordered_map
[       OK ] json.test_unordered_map (0 ms)
[ RUN      ] json.test_unordered_multimap
[       OK ] json.test_unordered_multimap (0 ms)
[ RUN      ] json.test_unordered_multiset
[       OK ] json.test_unordered_multiset (0 ms)
[ RUN      ] json.test_unordered_set
[       OK ] json.test_unordered_set (0 ms)
[ RUN      ] json.test_variant
[       OK ] json.test_variant (0 ms)
[ RUN      ] json.test_view
[       OK ] json.test_view (0 ms)
[ RUN      ] json.test_wstring
[       OK ] json.test_wstring (0 ms)
[----------] 141 tests from json (4 ms total)

[----------] Global test environment tear-down
[==========] 141 tests from 1 test suite ran. (4 ms total)
[  PASSED  ] 141 tests.

[Urfoex]

Refactored some rfl::visit code to use perfect forwarding. Which seem to help with Clang 19.
But now the benchmark fails. GCC14, Clang18, Clang19

reflect-cpp-json-benchmarks: /reflect-cpp/build_clang19/vcpkg_installed/x64-linux/include/rapidjson/document.h:1630: ConstObject rapidjson::GenericValue<rapidjson::UTF8<>>::GetObject() const [Encoding = rapidjson::UTF8<>, Allocator = rapidjson::MemoryPoolAllocator<>]: Assertion `IsObject()' failed.

[liuzicheng1987]

@Urfoex , it seems to work now...the checks all pass.