Merge #5741 and make keep the default error_handler of the binary writers

Merges claude/binary-utf8-roundtrip-5651, where the writers now only check
UTF-8 if JSON_STRICT_BINARY_UTF8 is enabled, and applies the same rule to
the error_handler parameter added here: to_cbor(), to_ubjson(),
to_bjdata(), and to_bson() default to error_handler_t::keep, the behavior
of 3.12.0, or to error_handler_t::strict if JSON_STRICT_BINARY_UTF8 is
enabled (detail::binary_writer_default_error_handler()). Passing a handler
explicitly always takes precedence.

- Conflicts in binary_writer.hpp resolved in favor of this branch's
  error_handler, which replaces #5741's check_text_utf8().
- Tests: the "default parameters" section checks that the default equals
  keep; unit-binary_utf8_strict.cpp checks that an explicit handler
  overrides the macro's default.
- Docs: signatures show keep; parameter, exception, and format pages
  describe keep as the default and the macro; the two 3.13.0 version
  history entries of each writer are merged into one.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann
2026-10-02 08:48:59 +02:00
33 changed files with 503 additions and 167 deletions
+4
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@@ -44,6 +44,10 @@ TEST_CASE("default namespace")
expected += "_snul";
#endif
#if JSON_STRICT_BINARY_UTF8
expected += "_sbu8";
#endif
expected += "_v" STRINGIZE(NLOHMANN_JSON_VERSION_MAJOR);
expected += "_" STRINGIZE(NLOHMANN_JSON_VERSION_MINOR);
expected += "_" STRINGIZE(NLOHMANN_JSON_VERSION_PATCH) "::basic_json";
+4
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@@ -45,6 +45,10 @@ TEST_CASE("default namespace without version component")
expected += "_snul";
#endif
#if JSON_STRICT_BINARY_UTF8
expected += "_sbu8";
#endif
expected += "::basic_json";
// fallback for Clang
+8 -5
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@@ -318,14 +318,17 @@ TEST_CASE("UTF-8 error_handler for the binary readers and writers")
{
const json jval = ill_formed_cases[0].bytes;
// to_*: the default error_handler is strict, so ill-formed input still throws
CHECK_THROWS_AS(json::to_cbor(jval), json::type_error&);
CHECK_THROWS_AS(json::to_ubjson(jval), json::type_error&);
CHECK_THROWS_AS(json::to_bjdata(jval), json::type_error&);
// to_*: the default error_handler is keep, so ill-formed bytes are
// written unchanged, exactly as in release 3.12.0 (it is strict only
// if JSON_STRICT_BINARY_UTF8 is enabled, see
// unit-binary_utf8_strict.cpp)
CHECK(json::to_cbor(jval) == json::to_cbor(jval, eh::keep));
CHECK(json::to_ubjson(jval) == json::to_ubjson(jval, false, false, eh::keep));
CHECK(json::to_bjdata(jval) == json::to_bjdata(jval, false, false, json::bjdata_version_t::draft2, eh::keep));
{
json jobj;
jobj["k"] = jval;
CHECK_THROWS_AS(json::to_bson(jobj), json::type_error&);
CHECK(json::to_bson(jobj) == json::to_bson(jobj, eh::keep));
}
// from_*: the default error_handler is keep, so ill-formed bytes are
+120
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@@ -0,0 +1,120 @@
// __ _____ _____ _____
// __| | __| | | | JSON for Modern C++ (supporting code)
// | | |__ | | | | | | version 3.12.0
// |_____|_____|_____|_|___| https://github.com/nlohmann/json
//
// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
// SPDX-License-Identifier: MIT
#include "doctest_compatibility.h"
// The binary writers check strings and object keys for valid UTF-8 only if
// JSON_STRICT_BINARY_UTF8 is enabled (planned to be the default in 4.0.0).
// Without it, they write the bytes unchanged, as before version 3.13.0; the
// tests for that are next to the other tests of each format.
#ifdef JSON_STRICT_BINARY_UTF8
#undef JSON_STRICT_BINARY_UTF8
#endif
#define JSON_STRICT_BINARY_UTF8 1
#include <nlohmann/json.hpp>
using nlohmann::json;
#include <cstdint>
#include <vector>
TEST_CASE("JSON_STRICT_BINARY_UTF8 (see #5529, #5651)")
{
SECTION("CBOR")
{
// a string value with ill-formed UTF-8 is rejected
CHECK_THROWS_WITH_AS(json::to_cbor(json("\xFF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
// a truncated multi-byte sequence
CHECK_THROWS_WITH_AS(json::to_cbor(json("\xC3")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC3", json::type_error&);
// an encoded surrogate half (U+D800)
CHECK_THROWS_WITH_AS(json::to_cbor(json("\xED\xA0\x80")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xED", json::type_error&);
// an overlong encoding of '.'
CHECK_THROWS_WITH_AS(json::to_cbor(json("\xC0\xAF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
// an object key with ill-formed UTF-8 is rejected the same way
CHECK_THROWS_WITH_AS(json::to_cbor(json{{"\xFF", 1}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
// binary values are not text and are unaffected
CHECK_NOTHROW(json::to_cbor(json::binary(std::vector<std::uint8_t>({0xFF}))));
// a value read back from CBOR with ill-formed bytes cannot be written
// back either (the reader is lenient regardless of the macro)
const json j = json::from_cbor(std::vector<std::uint8_t>({0x62, 0xc0, 0xae}));
CHECK_THROWS_WITH_AS(json::to_cbor(j), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
}
SECTION("UBJSON")
{
CHECK_THROWS_WITH_AS(json::to_ubjson(json("\xFF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
// a truncated multi-byte sequence
CHECK_THROWS_WITH_AS(json::to_ubjson(json("\xC3")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC3", json::type_error&);
// an encoded surrogate half (U+D800)
CHECK_THROWS_WITH_AS(json::to_ubjson(json("\xED\xA0\x80")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xED", json::type_error&);
// an overlong encoding of '.'
CHECK_THROWS_WITH_AS(json::to_ubjson(json("\xC0\xAF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
// an object key with ill-formed UTF-8 is rejected the same way
CHECK_THROWS_WITH_AS(json::to_ubjson(json{{"\xFF", 1}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
}
SECTION("BJData")
{
CHECK_THROWS_WITH_AS(json::to_bjdata(json("\xFF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
// a truncated multi-byte sequence
CHECK_THROWS_WITH_AS(json::to_bjdata(json("\xC3")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC3", json::type_error&);
// an encoded surrogate half (U+D800)
CHECK_THROWS_WITH_AS(json::to_bjdata(json("\xED\xA0\x80")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xED", json::type_error&);
// an overlong encoding of '.'
CHECK_THROWS_WITH_AS(json::to_bjdata(json("\xC0\xAF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
// an object key with ill-formed UTF-8 is rejected the same way
CHECK_THROWS_WITH_AS(json::to_bjdata(json{{"\xFF", 1}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
}
SECTION("BSON")
{
// to_bson() rejects the same kind of ill-formed string value, before
// any bytes reach the output adapter (the BSON document length
// prefix must be known up front, so nothing is written incrementally)
std::vector<std::uint8_t> out{0x42}; // a sentinel byte the writer must not touch
CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xFF"}}, nlohmann::detail::output_adapter<std::uint8_t>(out)), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
CHECK(out == std::vector<std::uint8_t> {0x42});
CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xFF"}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
// a truncated multi-byte sequence
CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xC3"}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC3", json::type_error&);
// an encoded surrogate half (U+D800)
CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xED\xA0\x80"}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xED", json::type_error&);
// an overlong encoding of '.'
CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xC0\xAF"}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
// an object key with ill-formed UTF-8 is rejected as well; unlike
// the reader (which never validates element names), the writer
// checks both string values and object keys
CHECK_THROWS_WITH_AS(json::to_bson(json{{"\xFF", 1}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
}
SECTION("an explicit error_handler overrides the default")
{
// the macro only changes the default of the error_handler parameter
CHECK(json::to_cbor(json("\xFF"), json::error_handler_t::keep) == std::vector<std::uint8_t>({0x61, 0xff}));
CHECK(json::to_ubjson(json("\xFF"), false, false, json::error_handler_t::keep) == std::vector<std::uint8_t>({'S', 'i', 1, 0xff}));
CHECK(json::to_bjdata(json("\xFF"), false, false, json::bjdata_version_t::draft2, json::error_handler_t::keep) == std::vector<std::uint8_t>({'S', 'i', 1, 0xff}));
CHECK(json::from_bson(json::to_bson(json{{"s", "\xFF"}}, json::error_handler_t::keep)) == json{{"s", "\xFF"}});
CHECK(json::to_cbor(json("\xFF"), json::error_handler_t::replace) == std::vector<std::uint8_t>({0x63, 0xef, 0xbf, 0xbd}));
}
SECTION("MessagePack and BON8 are unaffected")
{
// MessagePack allows any bytes in a str, so to_msgpack() writes them as
// is; BON8 always checks, because the lead bytes mark where strings end
CHECK(json::to_msgpack(json("\xFF")) == std::vector<std::uint8_t>({0xa1, 0xff}));
CHECK_THROWS_AS(json::to_bon8(json("\xFF")), json::type_error&);
}
}
+12 -10
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@@ -3913,15 +3913,17 @@ TEST_CASE("Universal Binary JSON Specification Examples 1")
// none of the binary format specs requires a decoder to reject
// ill-formed UTF-8 in a text string, so a value whose bytes are
// not valid UTF-8 (0xC0 0xAE is an overlong encoding of '.')
// round-trips byte for byte as a string value; to_bjdata() is
// strict, so such a value cannot be written back
// round-trips byte for byte as a string value; to_bjdata() writes
// the bytes unchanged, as before 3.13.0, unless
// JSON_STRICT_BINARY_UTF8 is enabled (see
// unit-binary_utf8_strict.cpp)
const std::vector<uint8_t> v = {'S', 'i', 2, 0xc0, 0xae};
json j;
CHECK_NOTHROW(j = json::from_bjdata(v));
REQUIRE(j.is_string());
CHECK(j.get_ref<const json::string_t&>() == std::string("\xc0\xae"));
CHECK_THROWS_AS(j.dump(), json::type_error&);
CHECK_THROWS_AS(json::to_bjdata(j), json::type_error&);
CHECK(json::from_bjdata(json::to_bjdata(j)) == j);
// the same bytes as an object key round-trip as well
const std::vector<uint8_t> v_key = {'{', 'i', 2, 0xc0, 0xae, 'i', 1, '}'};
@@ -3929,18 +3931,18 @@ TEST_CASE("Universal Binary JSON Specification Examples 1")
CHECK_NOTHROW(j_key = json::from_bjdata(v_key));
REQUIRE(j_key.is_object());
CHECK(j_key.contains(std::string("\xc0\xae")));
CHECK_THROWS_AS(json::to_bjdata(j_key), json::type_error&);
CHECK(json::from_bjdata(json::to_bjdata(j_key)) == j_key);
CHECK_THROWS_WITH_AS(json::to_bjdata(json("\xFF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
CHECK(json::from_bjdata(json::to_bjdata(json("\xFF"))) == json("\xFF"));
// a truncated multi-byte sequence
CHECK_THROWS_WITH_AS(json::to_bjdata(json("\xC3")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC3", json::type_error&);
CHECK(json::from_bjdata(json::to_bjdata(json("\xC3"))) == json("\xC3"));
// an encoded surrogate half (U+D800)
CHECK_THROWS_WITH_AS(json::to_bjdata(json("\xED\xA0\x80")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xED", json::type_error&);
CHECK(json::from_bjdata(json::to_bjdata(json("\xED\xA0\x80"))) == json("\xED\xA0\x80"));
// an overlong encoding of '.'
CHECK_THROWS_WITH_AS(json::to_bjdata(json("\xC0\xAF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
CHECK(json::from_bjdata(json::to_bjdata(json("\xC0\xAF"))) == json("\xC0\xAF"));
// an object key with ill-formed UTF-8 is rejected the same way
CHECK_THROWS_WITH_AS(json::to_bjdata(json{{"\xFF", 1}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
// an object key with ill-formed UTF-8 is kept the same way
CHECK(json::from_bjdata(json::to_bjdata(json{{"\xFF", 1}})) == json{{"\xFF", 1}});
}
}
+9 -17
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@@ -175,28 +175,20 @@ TEST_CASE("BSON")
CHECK(j["s"].get_ref<const json::string_t&>() == std::string("\xc0\xae"));
// dump() still requires valid UTF-8 and throws for such a value
CHECK_THROWS_AS(j.dump(), json::type_error&);
// to_bson() is strict as well, so the value cannot be written back
CHECK_THROWS_AS(json::to_bson(j), json::type_error&);
// to_bson() writes the bytes back unchanged, as before 3.13.0,
// unless JSON_STRICT_BINARY_UTF8 is enabled (see unit-binary_utf8_strict.cpp)
CHECK(json::from_bson(json::to_bson(j)) == j);
// to_bson() rejects the same kind of ill-formed string value, before
// any bytes reach the output adapter (the BSON document length
// prefix must be known up front, so nothing is written incrementally)
std::vector<std::uint8_t> out{0x42}; // a sentinel byte the writer must not touch
CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xFF"}}, nlohmann::detail::output_adapter<std::uint8_t>(out)), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
CHECK(out == std::vector<std::uint8_t> {0x42});
CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xFF"}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
CHECK(json::from_bson(json::to_bson(json{{"s", "\xFF"}})) == json{{"s", "\xFF"}});
// a truncated multi-byte sequence
CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xC3"}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC3", json::type_error&);
CHECK(json::from_bson(json::to_bson(json{{"s", "\xC3"}})) == json{{"s", "\xC3"}});
// an encoded surrogate half (U+D800)
CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xED\xA0\x80"}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xED", json::type_error&);
CHECK(json::from_bson(json::to_bson(json{{"s", "\xED\xA0\x80"}})) == json{{"s", "\xED\xA0\x80"}});
// an overlong encoding of '.'
CHECK_THROWS_WITH_AS(json::to_bson(json{{"s", "\xC0\xAF"}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
CHECK(json::from_bson(json::to_bson(json{{"s", "\xC0\xAF"}})) == json{{"s", "\xC0\xAF"}});
// an object key with ill-formed UTF-8 is rejected as well; unlike
// the reader (which never validates element names), the writer
// checks both string values and object keys
CHECK_THROWS_WITH_AS(json::to_bson(json{{"\xFF", 1}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
// an object key with ill-formed UTF-8 is kept as well
CHECK(json::from_bson(json::to_bson(json{{"\xFF", 1}})) == json{{"\xFF", 1}});
}
SECTION("lengths exceeding INT32_MAX cannot be serialized to BSON")
+15 -13
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@@ -1821,8 +1821,9 @@ TEST_CASE("CBOR")
// unless an error handler that replaces or ignores the bytes is
// passed
CHECK_THROWS_AS(j_value.dump(), json::type_error&);
// to_cbor() is strict as well, so the value cannot be written back
CHECK_THROWS_AS(json::to_cbor(j_value), json::type_error&);
// to_cbor() writes the bytes back unchanged, as before 3.13.0,
// unless JSON_STRICT_BINARY_UTF8 is enabled (see unit-binary_utf8_strict.cpp)
CHECK(json::from_cbor(json::to_cbor(j_value)) == j_value);
// the same bytes as an object key round-trip as well
const std::vector<uint8_t> ill_formed_key = {0xa1, 0x62, 0xc0, 0xae, 0x01};
@@ -1830,7 +1831,7 @@ TEST_CASE("CBOR")
CHECK_NOTHROW(j_key = json::from_cbor(ill_formed_key));
REQUIRE(j_key.is_object());
CHECK(j_key.contains(std::string("\xc0\xae")));
CHECK_THROWS_AS(json::to_cbor(j_key), json::type_error&);
CHECK(json::from_cbor(json::to_cbor(j_key)) == j_key);
// a CBOR byte string (major type 2) with the very same bytes is
// NOT text and must still be accepted as-is
@@ -1843,20 +1844,21 @@ TEST_CASE("CBOR")
CHECK(json::from_cbor(json::to_cbor(j)) == j);
}
SECTION("to_cbor rejects ill-formed UTF-8 (see #5651)")
SECTION("to_cbor keeps ill-formed UTF-8 (see #5651)")
{
// to_cbor() must reject the same ill-formed strings from_cbor()
// rejects, so a value it accepts can always be read back
CHECK_THROWS_WITH_AS(json::to_cbor(json("\xFF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
// to_cbor() writes the bytes unchanged, as before 3.13.0, unless
// JSON_STRICT_BINARY_UTF8 is enabled (see
// unit-binary_utf8_strict.cpp); from_cbor() reads them back as is
CHECK(json::from_cbor(json::to_cbor(json("\xFF"))) == json("\xFF"));
// a truncated multi-byte sequence
CHECK_THROWS_WITH_AS(json::to_cbor(json("\xC3")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC3", json::type_error&);
CHECK(json::from_cbor(json::to_cbor(json("\xC3"))) == json("\xC3"));
// an encoded surrogate half (U+D800)
CHECK_THROWS_WITH_AS(json::to_cbor(json("\xED\xA0\x80")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xED", json::type_error&);
CHECK(json::from_cbor(json::to_cbor(json("\xED\xA0\x80"))) == json("\xED\xA0\x80"));
// an overlong encoding of '.'
CHECK_THROWS_WITH_AS(json::to_cbor(json("\xC0\xAF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
CHECK(json::from_cbor(json::to_cbor(json("\xC0\xAF"))) == json("\xC0\xAF"));
// an object key with ill-formed UTF-8 is rejected the same way
CHECK_THROWS_WITH_AS(json::to_cbor(json{{"\xFF", 1}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
// an object key with ill-formed UTF-8 is kept the same way
CHECK(json::from_cbor(json::to_cbor(json{{"\xFF", 1}})) == json{{"\xFF", 1}});
// binary values are not text and are unaffected
CHECK_NOTHROW(json::to_cbor(json::binary(std::vector<std::uint8_t>({0xFF}))));
@@ -1877,7 +1879,7 @@ TEST_CASE("CBOR")
CHECK_NOTHROW(_ = json::from_cbor(std::vector<uint8_t>({0x7f, 0x61, 0xc3, 0xff})));
CHECK(_ == "\xc3");
CHECK_THROWS_AS(_.dump(), json::type_error&);
CHECK_THROWS_AS(json::to_cbor(_), json::type_error&);
CHECK(json::from_cbor(json::to_cbor(_)) == _);
// an ill-formed later chunk is kept after valid ones
CHECK_NOTHROW(_ = json::from_cbor(std::vector<uint8_t>({0x7f, 0x62, 0xc3, 0xa9, 0x62, 0xc0, 0xae, 0xff})));
+12 -10
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@@ -2511,15 +2511,17 @@ TEST_CASE("Universal Binary JSON Specification Examples 1")
// none of the binary format specs requires a decoder to reject
// ill-formed UTF-8 in a text string, so a value whose bytes are
// not valid UTF-8 (0xC0 0xAE is an overlong encoding of '.')
// round-trips byte for byte as a string value; to_ubjson() is
// strict, so such a value cannot be written back
// round-trips byte for byte as a string value; to_ubjson() writes
// the bytes unchanged, as before 3.13.0, unless
// JSON_STRICT_BINARY_UTF8 is enabled (see
// unit-binary_utf8_strict.cpp)
const std::vector<uint8_t> v = {'S', 'i', 2, 0xc0, 0xae};
json j;
CHECK_NOTHROW(j = json::from_ubjson(v));
REQUIRE(j.is_string());
CHECK(j.get_ref<const json::string_t&>() == std::string("\xc0\xae"));
CHECK_THROWS_AS(j.dump(), json::type_error&);
CHECK_THROWS_AS(json::to_ubjson(j), json::type_error&);
CHECK(json::from_ubjson(json::to_ubjson(j)) == j);
// the same bytes as an object key round-trip as well
const std::vector<uint8_t> v_key = {'{', 'i', 2, 0xc0, 0xae, 'i', 1, '}'};
@@ -2527,18 +2529,18 @@ TEST_CASE("Universal Binary JSON Specification Examples 1")
CHECK_NOTHROW(j_key = json::from_ubjson(v_key));
REQUIRE(j_key.is_object());
CHECK(j_key.contains(std::string("\xc0\xae")));
CHECK_THROWS_AS(json::to_ubjson(j_key), json::type_error&);
CHECK(json::from_ubjson(json::to_ubjson(j_key)) == j_key);
CHECK_THROWS_WITH_AS(json::to_ubjson(json("\xFF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
CHECK(json::from_ubjson(json::to_ubjson(json("\xFF"))) == json("\xFF"));
// a truncated multi-byte sequence
CHECK_THROWS_WITH_AS(json::to_ubjson(json("\xC3")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC3", json::type_error&);
CHECK(json::from_ubjson(json::to_ubjson(json("\xC3"))) == json("\xC3"));
// an encoded surrogate half (U+D800)
CHECK_THROWS_WITH_AS(json::to_ubjson(json("\xED\xA0\x80")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xED", json::type_error&);
CHECK(json::from_ubjson(json::to_ubjson(json("\xED\xA0\x80"))) == json("\xED\xA0\x80"));
// an overlong encoding of '.'
CHECK_THROWS_WITH_AS(json::to_ubjson(json("\xC0\xAF")), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xC0", json::type_error&);
CHECK(json::from_ubjson(json::to_ubjson(json("\xC0\xAF"))) == json("\xC0\xAF"));
// an object key with ill-formed UTF-8 is rejected the same way
CHECK_THROWS_WITH_AS(json::to_ubjson(json{{"\xFF", 1}}), "[json.exception.type_error.316] invalid UTF-8 byte at index 0: 0xFF", json::type_error&);
// an object key with ill-formed UTF-8 is kept the same way
CHECK(json::from_ubjson(json::to_ubjson(json{{"\xFF", 1}})) == json{{"\xFF", 1}});
}
}