Release date: 2020-06-14

SHA-256: be7bbfbc7c62c35aa6f27dfbdd950384f247dd9f2281b5930bdaa3a6ab95eef7 (json.hpp), 8590fbcc2346a3eefc341935765dd57598022ada1081b425678f0da9a939a3c0 (include.zip)

It has been six months since the last release, and a lot of minor changes and bug fixes have accumulated. Nonetheless, JSON for Modern C++ 3.8.0 is a feature release.

- With **binary values** we greatly extend the support for binary formats such as CBOR, BSON, or MessagePack. By adding a new value type to the JSON class, binary values can be read and written, and even shared between different formats. See [the documentation](https://github.com/nlohmann/json#binary-formats-bson-cbor-messagepack-and-ubjson) for examples.

- Furthermore, we overworked the **input adapters**; that is, the way input is read by the parsers. Now any container is supported via the `LegacyInputIterator` concept. See [the documentation](https://github.com/nlohmann/json#custom-data-source) for examples. At the same time, we could improve the performance by 3-10%.

All changes are backward-compatible. See below the complete list of changes.

:moneybag: Note you can now **support this project** via [GitHub sponsors](https://github.com/sponsors/nlohmann) or [PayPal](http://paypal.me/nlohmann).

- The library now supports binary values for CBOR (byte arrays), BSON, and MessagePack (bin, ext, fixext). The values are parsed into a byte vector for further processing. #483 #757 #1129 #1509 #1662 #1668 #2064 #2069 #2071 #2082 #2099
- The input adapters have been generalized to read from any container including user-defined containers via `LegacyInputIterator`. The encoding of the input is implicitly derived from the size of the value type: UTF-8 (1 byte), UTF-16 (2 bytes), and UTF-32 (4 bytes) are supported. #1813 #2145 #2174 #2178
- CBOR now encodes floating-point numbers that can be represented by a `float` as `float` to save space in the serialization (32 bit va. 64 bit). #1719 #2044

- The functions to parse binary formats (`from_bson`, `from_cbor`, `from_msgpack`, and `from_ubjson`) now properly respect the `allow_exceptions=false` parameter. #1715 #2140
- The `contains` function for JSON Pointers now returns `false` in all cases a syntactically correct JSON Pointer refers to a non-existing value. Previously, an exception was raised if a JSON Pointer referred to an array, but did not consist of a number. #1942 #1982 #2019
- Fixed the JSON Pointer parser which accepted numbers with leading `+` as array index. #1990
- Fixed JSON Patch generation to properly use `/-` in the `add` operation for arrays. #1983 #2054
- Fixed compilation errors using GCC 10. #1912 #1920 #2034
- Fixed compilation errors using MSVC 2019. #1695 #1810 #1958 #2006 #2008 #2009
- Fixed a preprocessor check for some MSVC versions. #2112 #2137
- Fixed possible memory leak in `push_back`. #1971 #2025
- Removed broken overload of the `value()` function with `json::value_t type` parameter. #2086 #2104
- Removed values from arrays in case they are discarded by a parser callback function. Such values remained in the array with type `discarded` before. #1972 #2153

- The input adapters are now used via templates rather than inheriting from an abstract base class. This brings a 3-10% speedup for all parsers. #1457 #1950
- Test files are now downloaded from an [external repository](https://github.com/nlohmann/json_test_data) such that the code repository got much smaller and can be used as submodule more easily. #96 #482 #556 #567 #620 #732 #1066 #1184 #1185 #1235 #1497 #1572 #1790 #2081
- Made CMake's version config file architecture-independent. #1697 #1746

- Added links to [GitHub sponsors](https://github.com/sponsors/nlohmann) and listed named sponsors.
- Documented the integration of the library via CMake [FetchContent](https://cmake.org/cmake/help/v3.11/module/FetchContent.html) #2073 #2074
- Doozer CI was removed as it seems to exist no longer. #2080
- Added GitHub Actions workflows to build with Ubuntu, macOS, and Windows.
- Added GCC 10.1 to the continuous integration. #2136
- Fixed the Coveralls integration. #2100
- Fixed the error message for invalid surrogate pairs. #2076
- Fixed documentation. #1853 #1857 #1895 #1903 #1907 #1915 #1917 #1918 #1923 #1956 #1979 #1980 #2002 #2060 #2077 #2142 #2143 #2152
- Added test cases for NaN value in CBOR. #2043
- Documented curious behavior when using the library with glibc. #1924 #1933
- Fixed compiler warnings. #1939 #1911 #1967 #1969 #2049 #2051 #2053 #2113 #2116 #2144 #2177
- Updated Doctest to version 2.3.7. #2048 #2050
- Updated Hedley to version 13.
- Removed `std::is_pod` usage as it is deprecated in C++20. #1913 #2033 #2109
- Added [wsjcpp](https://wsjcpp.org) package manager. #2004
- Added [Build2](https://build2.org/) package manager. #1909
- Fixed compiler warning in test case. #1871
- Updated copyright year. #2010
- Updated CMake tests. #1844
- Removed a duplicated test. #2158
- Removed outdated Travis macOS images for Xcode 8.3, Xcode 9.0, Xcode 9.1, and Xcode 9.2. Added Xcode 11.2 image.
- Added [FOSSA](https://app.fossa.com/projects/git%2Bgithub.com%2Fnlohmann%2Fjson?ref=badge_shield) analysis.
- Header `<ciso646>` is deprecated in C++17 and not included if library is compiled with C++17. #2089 .#2115
- Updated the templates for bug fix reports, feature requests, and questions.
- Added fuzz tests for the all UBJSON modes. #2182
- Used [`HEDLEY_DEPRECATED_FOR`](https://nemequ.github.io/hedley/api-reference.html#HEDLEY_DEPRECATED_FOR) to indicate deprecated functions to have supporting compilers report which function to use instead.

This release deprecates passing iterator pairs or pointer/length pairs to parsing functions (`basic_json::parse`, `basic_json::accept`, `basic_json::sax_parse`, `basic_json::from_cbor`, `basic_json::from_msgpack`, `basic_json::from_ubjson`, `basic_json::from_bson`) via initializer lists. Instead, pass the elements individually without braces.

The following functions have been deprecated in earlier versions and will be removed in the next major version (i.e., 4.0.0):

- Function [`iterator_wrapper`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a0a8051760196ac813fd5eb3c8d5a2976.html#a0a8051760196ac813fd5eb3c8d5a2976) are deprecated. Please use the member function [`items()`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a5961446010dfc494e0c247b4e9026977.html#a5961446010dfc494e0c247b4e9026977) instead.
- Functions [`friend std::istream& operator<<(basic_json&, std::istream&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a60ca396028b8d9714c6e10efbf475af6.html#a60ca396028b8d9714c6e10efbf475af6) and [`friend std::ostream& operator>>(const basic_json&, std::ostream&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a34d6a60dd99e9f33b8273a1c8db5669b.html#a34d6a60dd99e9f33b8273a1c8db5669b) are deprecated. Please use [`friend std::istream&  operator>>(std::istream&, basic_json&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_aaf363408931d76472ded14017e59c9e8.html#aaf363408931d76472ded14017e59c9e8) and [`friend operator<<(std::ostream&, const basic_json&)`](https://nlohmann.github.io/json/doxygen/classnlohmann_1_1basic__json_a5e34c5435e557d0bf666bd7311211405.html#a5e34c5435e557d0bf666bd7311211405) instead.

All deprecations are annotated with [`HEDLEY_DEPRECATED_FOR`](https://nemequ.github.io/hedley/api-reference.html#HEDLEY_DEPRECATED_FOR) to report which function to use instead.