amorfo77/json
1
0
Fork 0
mirror of https://github.com/nlohmann/json.git synced 2026-10-04 13:40:33 +00:00
Code Issues Packages Projects Releases Wiki Activity

Add JSON_DISABLE_TUPLE_REFERENCE_CONVERSION to fix std::tuple conversions

Browse Source 
basic_json can be constructed from std::tuple<json&>, which it turns into
a one-element array. Because of this, std::tuple picks its converting
constructor that converts the whole source tuple instead of the
element-wise one. As a result, std::tuple<const json&> built from
std::forward_as_tuple(j) binds to a temporary (a compile error with libc++,
a dangling reference with other standard libraries), and std::tuple<json>
built the same way holds [j] instead of a copy of j.

The new opt-in macro JSON_DISABLE_TUPLE_REFERENCE_CONVERSION (CMake option
JSON_DisableTupleReferenceConversion) removes the conversion from a
one-element tuple holding a reference to the same basic_json type, so
std::tuple converts element-wise. It is off by default, so existing
behavior is unchanged. It does not change any function body and therefore
is not part of the ABI tag.

Fixes #2226

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann
2026-09-27 17:17:51 +02:00
parent f682cd2ef1
commit c5f1694b01
17 changed files with 296 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files
docs/mkdocs/mkdocs.yml
+1
View File
@@ -284,6 +284,7 @@ nav:
- 'JSON_DIAGNOSTICS': api/macros/json_diagnostics.md
- 'JSON_DIAGNOSTIC_POSITIONS': api/macros/json_diagnostic_positions.md
- 'JSON_DISABLE_ENUM_SERIALIZATION': api/macros/json_disable_enum_serialization.md
- 'JSON_DISABLE_TUPLE_REFERENCE_CONVERSION': api/macros/json_disable_tuple_reference_conversion.md
- 'JSON_HAS_CPP_11, JSON_HAS_CPP_14, JSON_HAS_CPP_17, JSON_HAS_CPP_20': api/macros/json_has_cpp_11.md
- 'JSON_HAS_EXPERIMENTAL_FILESYSTEM, JSON_HAS_FILESYSTEM': api/macros/json_has_filesystem.md
- 'JSON_HAS_RANGES': api/macros/json_has_ranges.md