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Author SHA1 Message Date
Niels Lohmann cc749ac699 Keep full byte2 x byte3 combinatorics in the wrong-fourth-byte sections
The maintainer wants exhaustive coverage of every byte combination here
rather than the representative-prefix reduction, matching the style of
the sibling "wrong second/third byte" sections in the same files.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-05 23:18:51 +02:00
Niels Lohmann 1c6ca81b8a Fix dead ill-formed-fourth-byte UTF-8 test sections (byte3/byte4 typo)
The "ill-formed: wrong fourth byte" SECTIONs in unit-unicode3.cpp,
unit-unicode4.cpp, and unit-unicode5.cpp guarded their loop with a check
on byte3 instead of byte4. Since the enclosing loop already restricts
byte3 to its valid range, the guard was always true and the section's
"continue" fired unconditionally, so check_utf8string()/check_utf8dump()
were never actually invoked for a malformed fourth byte.

Fixing the guard naively (byte3 -> byte4) would also have swept the full
byte2 x byte3 combinatorics for every byte4 value, adding millions of
redundant iterations: the lexer validates continuation bytes strictly in
sequence with early exit (see next_byte_in_range() in lexer.hpp), so once
byte2/byte3 are within their valid range, the byte4 outcome does not
depend on which valid byte2/byte3 values were chosen. Instead, byte2 and
byte3 are now held to a small hedge of representative valid prefixes
(range corners plus a midpoint) while byte4 is still swept exhaustively
over its full 0x00-0xFF range, since that is the actual property under
test. Also fixed the garbled "skip fourth second byte" comment in
unit-unicode3.cpp.

Verified offline: before the fix, the "wrong fourth byte" subcase
executes 0 assertions in all three files (proving it was dead code);
after the fix, it executes 11520 (unicode3), 34560 (unicode4), and 11520
(unicode5) assertions, and a deliberately reintroduced bug in the
lexer's byte4 range check causes it to fail (proving it is now
meaningful). Total per-file assertion counts grow by the same small
amounts, not by millions, and all other sections in these files still
pass unchanged.

Fixes #5416

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-05 23:05:42 +02:00
8 changed files with 28 additions and 422 deletions
+5 -128
View File
@@ -149,11 +149,10 @@ class lexer : public lexer_base<BasicJsonType>
public:
using token_type = typename lexer_base<BasicJsonType>::token_type;
explicit lexer(InputAdapterType&& adapter, bool ignore_comments_ = false, bool discard_number_values_ = false) noexcept
explicit lexer(InputAdapterType&& adapter, bool ignore_comments_ = false) noexcept
: ia(std::move(adapter))
, ignore_comments(ignore_comments_)
, decimal_point_char(static_cast<char_int_type>(get_decimal_point()))
, discard_number_values(discard_number_values_)
{}
// deleted because of pointer members
@@ -1280,58 +1279,6 @@ scan_number_done:
// we are done scanning a number)
unget();
// If the caller does not need the converted value (only whether the
// input is syntactically valid; see json_sax_acceptor/accept()), an
// unsigned/integer token can be reported without calling
// strtoull()/strtoll() at all, *provided* we can already tell from
// the digit count alone that the conversion cannot overflow 64 bits.
// Such tokens are always finite and are accepted unconditionally by
// the parser regardless of their actual value (parser::sax_parse_internal()
// never checks finiteness for value_unsigned/value_integer), so the
// classification below is all that is needed.
//
// A decimal number with up to 18 digits is always representable in
// both std::uint64_t and std::int64_t (18 nines is ~1e18, well below
// both UINT64_MAX ~1.8e19 and INT64_MAX ~9.2e18), so strtoull()/strtoll()
// could not have set errno to ERANGE for it. Numbers with more digits
// (rare in practice) fall through to the exact code below, unchanged,
// so their handling -- including reclassification to value_float when
// the value overflows 64 bits, and rejection when it is not even
// finite as a double -- is bit-for-bit identical to before this
// optimization.
//
// Note this reasons about std::uint64_t/std::int64_t, not about
// number_unsigned_t/number_integer_t (BasicJsonType's own, possibly
// narrower, template parameters -- e.g. std::uint32_t). That is fine
// *only* because discard_number_values is exclusively set by
// accept() (see json.hpp), and accept() always parses through the
// library's own json_sax_acceptor -- never a user-supplied SAX
// consumer -- whose number_unsigned()/number_integer()/number_float()
// callbacks unconditionally discard their argument and return true.
// So for every caller that can reach this branch, neither the token
// classification below nor the eventual (possibly narrowed, and on
// this fast path left stale/unset) value_unsigned/value_integer is
// ever consulted -- an unsigned/integer token is accepted outright,
// and even a >18-digit token that this fast path deliberately falls
// through for is, once reclassified to value_float, still finite
// (and thus accepted) for any digit count that fits in number_unsigned_t
// or number_integer_t regardless of that type's width. If this
// function is ever taught to run with discard_number_values true for
// a caller that *does* read the converted value, this reasoning (and
// the fast path below) would need to be revisited.
if (discard_number_values)
{
constexpr std::size_t safe_digit_count = 18;
if (number_type == token_type::value_unsigned && token_buffer.size() <= safe_digit_count)
{
return token_type::value_unsigned;
}
if (number_type == token_type::value_integer && token_buffer.size() - 1 <= safe_digit_count)
{
return token_type::value_integer;
}
}
char* endptr = nullptr; // NOLINT(misc-const-correctness,cppcoreguidelines-pro-type-vararg,hicpp-vararg)
errno = 0;
@@ -1446,7 +1393,8 @@ scan_number_done:
*/
char_int_type get()
{
advance_position();
++position.chars_read_total;
++position.chars_read_current_line;
if (next_unget)
{
@@ -1458,23 +1406,6 @@ scan_number_done:
current = ia.get_character();
}
return track_after_read();
}
/// shared head of get() / get_ignoring_pending_unget(): bump the
/// per-character position counters (line-count-on-'\n' bookkeeping is
/// handled afterwards, in track_after_read(), once `current` is known)
void advance_position() noexcept
{
++position.chars_read_total;
++position.chars_read_current_line;
}
/// shared tail of get() / get_ignoring_pending_unget(): capture the
/// character for error messages (if needed) and update line/column
/// bookkeeping for the character now in `current`
char_int_type track_after_read()
{
// seekable adapters reconstruct the token lazily on error (see
// get_token_string), so the eager per-character copy is skipped
capture_char(std::integral_constant<bool, lazy_token_string> {});
@@ -1488,29 +1419,6 @@ scan_number_done:
return current;
}
/*!
@brief like get(), but for call sites that can prove no unget() is pending
get() has to check the `next_unget` flag on every call, because a
previous token may have ended with unget() (e.g. scan_number() always
ungets the character that terminated the number, so the next call to
scan() can see it again). skip_whitespace() reads that first,
possibly-ungotten character via a plain get(), but every further
character it reads is guaranteed to be a fresh read: nothing between
those calls invokes unget(). This variant skips the (otherwise always
false) next_unget branch for those calls; it is not a general
replacement for get().
*/
char_int_type get_ignoring_pending_unget()
{
JSON_ASSERT(!next_unget);
advance_position();
current = ia.get_character();
return track_after_read();
}
/// seekable adapter: nothing to capture, the token is rebuilt on error
void capture_char(std::true_type /*lazy*/) const noexcept {}
@@ -1704,37 +1612,13 @@ scan_number_done:
return true;
}
/// whether `current` is one of the four JSON whitespace characters
bool current_is_whitespace() const noexcept
{
return current == ' ' || current == '\t' || current == '\n' || current == '\r';
}
void skip_whitespace()
{
// the first character may be a pending unget() left over from the
// previous token (see get_ignoring_pending_unget()); every
// subsequent character read by this loop is guaranteed fresh, since
// nothing below calls unget()
get();
if (!current_is_whitespace())
{
return;
}
// this is written as an if-guarded do-while (rather than a plain
// while loop) because that shape is what lets both GCC and Clang
// keep the input adapter's read pointer in a register across
// iterations; the equivalent while-loop measurably defeated that
// optimization in testing, turning long whitespace runs (e.g. the
// indentation of pretty-printed JSON) from a register-only loop
// into one that reloads the pointer from memory every character
do
{
get_ignoring_pending_unget();
get();
}
while (current_is_whitespace());
while (current == ' ' || current == '\t' || current == '\n' || current == '\r');
}
token_type scan()
@@ -1870,13 +1754,6 @@ scan_number_done:
const char_int_type decimal_point_char = '.';
/// the position of the decimal point in the input
std::size_t decimal_point_position = std::string::npos;
/// whether the caller (e.g. accept()/json_sax_acceptor) only needs the
/// token classification and never looks at the converted numeric value;
/// when set, scan_number() may skip strtoull()/strtoll() for
/// value_unsigned/value_integer tokens whose digit count guarantees they
/// fit into 64 bits (see scan_number())
const bool discard_number_values = false;
};
} // namespace detail
+2 -3
View File
@@ -72,10 +72,9 @@ class parser
parser_callback_t<BasicJsonType> cb = nullptr,
const bool allow_exceptions_ = true,
const bool ignore_comments = false,
const bool ignore_trailing_commas_ = false,
const bool discard_number_values_ = false)
const bool ignore_trailing_commas_ = false)
: callback(std::move(cb))
, m_lexer(std::move(adapter), ignore_comments, discard_number_values_)
, m_lexer(std::move(adapter), ignore_comments)
, allow_exceptions(allow_exceptions_)
, ignore_trailing_commas(ignore_trailing_commas_)
{
+5 -6
View File
@@ -164,12 +164,11 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
detail::parser_callback_t<basic_json>cb = nullptr,
const bool allow_exceptions = true,
const bool ignore_comments = false,
const bool ignore_trailing_commas = false,
const bool discard_number_values = false
const bool ignore_trailing_commas = false
)
{
return ::nlohmann::detail::parser<basic_json, InputAdapterType>(std::move(adapter),
std::move(cb), allow_exceptions, ignore_comments, ignore_trailing_commas, discard_number_values);
std::move(cb), allow_exceptions, ignore_comments, ignore_trailing_commas);
}
private:
@@ -4134,7 +4133,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
const bool ignore_comments = false,
const bool ignore_trailing_commas = false)
{
return parser(detail::input_adapter(std::forward<InputType>(i)), nullptr, false, ignore_comments, ignore_trailing_commas, true).accept(true);
return parser(detail::input_adapter(std::forward<InputType>(i)), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
}
/// @brief check if the input is valid JSON (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -4145,7 +4144,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
const bool ignore_comments = false,
const bool ignore_trailing_commas = false)
{
return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments, ignore_trailing_commas, true).accept(true);
return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
}
JSON_HEDLEY_WARN_UNUSED_RESULT
@@ -4154,7 +4153,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
const bool ignore_comments = false,
const bool ignore_trailing_commas = false)
{
return parser(i.get(), nullptr, false, ignore_comments, ignore_trailing_commas, true).accept(true);
return parser(i.get(), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
}
/// @brief generate SAX events
+12 -137
View File
@@ -7932,11 +7932,10 @@ class lexer : public lexer_base<BasicJsonType>
public:
using token_type = typename lexer_base<BasicJsonType>::token_type;
explicit lexer(InputAdapterType&& adapter, bool ignore_comments_ = false, bool discard_number_values_ = false) noexcept
explicit lexer(InputAdapterType&& adapter, bool ignore_comments_ = false) noexcept
: ia(std::move(adapter))
, ignore_comments(ignore_comments_)
, decimal_point_char(static_cast<char_int_type>(get_decimal_point()))
, discard_number_values(discard_number_values_)
{}
// deleted because of pointer members
@@ -9063,58 +9062,6 @@ scan_number_done:
// we are done scanning a number)
unget();
// If the caller does not need the converted value (only whether the
// input is syntactically valid; see json_sax_acceptor/accept()), an
// unsigned/integer token can be reported without calling
// strtoull()/strtoll() at all, *provided* we can already tell from
// the digit count alone that the conversion cannot overflow 64 bits.
// Such tokens are always finite and are accepted unconditionally by
// the parser regardless of their actual value (parser::sax_parse_internal()
// never checks finiteness for value_unsigned/value_integer), so the
// classification below is all that is needed.
//
// A decimal number with up to 18 digits is always representable in
// both std::uint64_t and std::int64_t (18 nines is ~1e18, well below
// both UINT64_MAX ~1.8e19 and INT64_MAX ~9.2e18), so strtoull()/strtoll()
// could not have set errno to ERANGE for it. Numbers with more digits
// (rare in practice) fall through to the exact code below, unchanged,
// so their handling -- including reclassification to value_float when
// the value overflows 64 bits, and rejection when it is not even
// finite as a double -- is bit-for-bit identical to before this
// optimization.
//
// Note this reasons about std::uint64_t/std::int64_t, not about
// number_unsigned_t/number_integer_t (BasicJsonType's own, possibly
// narrower, template parameters -- e.g. std::uint32_t). That is fine
// *only* because discard_number_values is exclusively set by
// accept() (see json.hpp), and accept() always parses through the
// library's own json_sax_acceptor -- never a user-supplied SAX
// consumer -- whose number_unsigned()/number_integer()/number_float()
// callbacks unconditionally discard their argument and return true.
// So for every caller that can reach this branch, neither the token
// classification below nor the eventual (possibly narrowed, and on
// this fast path left stale/unset) value_unsigned/value_integer is
// ever consulted -- an unsigned/integer token is accepted outright,
// and even a >18-digit token that this fast path deliberately falls
// through for is, once reclassified to value_float, still finite
// (and thus accepted) for any digit count that fits in number_unsigned_t
// or number_integer_t regardless of that type's width. If this
// function is ever taught to run with discard_number_values true for
// a caller that *does* read the converted value, this reasoning (and
// the fast path below) would need to be revisited.
if (discard_number_values)
{
constexpr std::size_t safe_digit_count = 18;
if (number_type == token_type::value_unsigned && token_buffer.size() <= safe_digit_count)
{
return token_type::value_unsigned;
}
if (number_type == token_type::value_integer && token_buffer.size() - 1 <= safe_digit_count)
{
return token_type::value_integer;
}
}
char* endptr = nullptr; // NOLINT(misc-const-correctness,cppcoreguidelines-pro-type-vararg,hicpp-vararg)
errno = 0;
@@ -9229,7 +9176,8 @@ scan_number_done:
*/
char_int_type get()
{
advance_position();
++position.chars_read_total;
++position.chars_read_current_line;
if (next_unget)
{
@@ -9241,23 +9189,6 @@ scan_number_done:
current = ia.get_character();
}
return track_after_read();
}
/// shared head of get() / get_ignoring_pending_unget(): bump the
/// per-character position counters (line-count-on-'\n' bookkeeping is
/// handled afterwards, in track_after_read(), once `current` is known)
void advance_position() noexcept
{
++position.chars_read_total;
++position.chars_read_current_line;
}
/// shared tail of get() / get_ignoring_pending_unget(): capture the
/// character for error messages (if needed) and update line/column
/// bookkeeping for the character now in `current`
char_int_type track_after_read()
{
// seekable adapters reconstruct the token lazily on error (see
// get_token_string), so the eager per-character copy is skipped
capture_char(std::integral_constant<bool, lazy_token_string> {});
@@ -9271,29 +9202,6 @@ scan_number_done:
return current;
}
/*!
@brief like get(), but for call sites that can prove no unget() is pending
get() has to check the `next_unget` flag on every call, because a
previous token may have ended with unget() (e.g. scan_number() always
ungets the character that terminated the number, so the next call to
scan() can see it again). skip_whitespace() reads that first,
possibly-ungotten character via a plain get(), but every further
character it reads is guaranteed to be a fresh read: nothing between
those calls invokes unget(). This variant skips the (otherwise always
false) next_unget branch for those calls; it is not a general
replacement for get().
*/
char_int_type get_ignoring_pending_unget()
{
JSON_ASSERT(!next_unget);
advance_position();
current = ia.get_character();
return track_after_read();
}
/// seekable adapter: nothing to capture, the token is rebuilt on error
void capture_char(std::true_type /*lazy*/) const noexcept {}
@@ -9487,37 +9395,13 @@ scan_number_done:
return true;
}
/// whether `current` is one of the four JSON whitespace characters
bool current_is_whitespace() const noexcept
{
return current == ' ' || current == '\t' || current == '\n' || current == '\r';
}
void skip_whitespace()
{
// the first character may be a pending unget() left over from the
// previous token (see get_ignoring_pending_unget()); every
// subsequent character read by this loop is guaranteed fresh, since
// nothing below calls unget()
get();
if (!current_is_whitespace())
{
return;
}
// this is written as an if-guarded do-while (rather than a plain
// while loop) because that shape is what lets both GCC and Clang
// keep the input adapter's read pointer in a register across
// iterations; the equivalent while-loop measurably defeated that
// optimization in testing, turning long whitespace runs (e.g. the
// indentation of pretty-printed JSON) from a register-only loop
// into one that reloads the pointer from memory every character
do
{
get_ignoring_pending_unget();
get();
}
while (current_is_whitespace());
while (current == ' ' || current == '\t' || current == '\n' || current == '\r');
}
token_type scan()
@@ -9653,13 +9537,6 @@ scan_number_done:
const char_int_type decimal_point_char = '.';
/// the position of the decimal point in the input
std::size_t decimal_point_position = std::string::npos;
/// whether the caller (e.g. accept()/json_sax_acceptor) only needs the
/// token classification and never looks at the converted numeric value;
/// when set, scan_number() may skip strtoull()/strtoll() for
/// value_unsigned/value_integer tokens whose digit count guarantees they
/// fit into 64 bits (see scan_number())
const bool discard_number_values = false;
};
} // namespace detail
@@ -14166,10 +14043,9 @@ class parser
parser_callback_t<BasicJsonType> cb = nullptr,
const bool allow_exceptions_ = true,
const bool ignore_comments = false,
const bool ignore_trailing_commas_ = false,
const bool discard_number_values_ = false)
const bool ignore_trailing_commas_ = false)
: callback(std::move(cb))
, m_lexer(std::move(adapter), ignore_comments, discard_number_values_)
, m_lexer(std::move(adapter), ignore_comments)
, allow_exceptions(allow_exceptions_)
, ignore_trailing_commas(ignore_trailing_commas_)
{
@@ -21716,12 +21592,11 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
detail::parser_callback_t<basic_json>cb = nullptr,
const bool allow_exceptions = true,
const bool ignore_comments = false,
const bool ignore_trailing_commas = false,
const bool discard_number_values = false
const bool ignore_trailing_commas = false
)
{
return ::nlohmann::detail::parser<basic_json, InputAdapterType>(std::move(adapter),
std::move(cb), allow_exceptions, ignore_comments, ignore_trailing_commas, discard_number_values);
std::move(cb), allow_exceptions, ignore_comments, ignore_trailing_commas);
}
private:
@@ -25686,7 +25561,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
const bool ignore_comments = false,
const bool ignore_trailing_commas = false)
{
return parser(detail::input_adapter(std::forward<InputType>(i)), nullptr, false, ignore_comments, ignore_trailing_commas, true).accept(true);
return parser(detail::input_adapter(std::forward<InputType>(i)), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
}
/// @brief check if the input is valid JSON (iterator pair, or iterator+sentinel pair for C++20 ranges support)
@@ -25697,7 +25572,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
const bool ignore_comments = false,
const bool ignore_trailing_commas = false)
{
return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments, ignore_trailing_commas, true).accept(true);
return parser(detail::input_adapter(std::move(first), std::move(last)), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
}
JSON_HEDLEY_WARN_UNUSED_RESULT
@@ -25706,7 +25581,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
const bool ignore_comments = false,
const bool ignore_trailing_commas = false)
{
return parser(i.get(), nullptr, false, ignore_comments, ignore_trailing_commas, true).accept(true);
return parser(i.get(), nullptr, false, ignore_comments, ignore_trailing_commas).accept(true);
}
/// @brief generate SAX events
-144
View File
@@ -930,94 +930,6 @@ TEST_CASE("parser class")
CHECK(accept_helper("+1") == false);
CHECK(accept_helper("+0") == false);
}
SECTION("issue #5411 - skip conversion when accept() does not need the numeric value")
{
// lexer::scan_number() may skip strtoull()/strtoll() for
// value_unsigned/value_integer tokens when the caller (e.g.
// json::accept()) does not need the converted value, as long
// as the digit count alone guarantees no 64-bit overflow (see
// the "safe_digit_count" fast path in scan_number()). This
// differential test checks that json::accept() (which enables
// the fast path) and json::parse() (which never does) always
// agree, over a corpus that exercises both the fast path
// (<=18 digits) and the untouched, exact fallback path (>=19
// digits) -- including reclassification of huge digit-only
// integers to a (possibly non-finite) floating-point value.
const std::vector<std::pair<std::string, bool>> cases =
{
// normal small/large integers, both signs
{"0", true}, {"1", true}, {"-1", true}, {"42", true}, {"-42", true},
{"123456789", true}, {"-123456789", true},
// digit-count boundary around the 18-digit safe cutoff (both signs)
{std::string(17, '9'), true},
{std::string(18, '9'), true},
{std::string(19, '9'), true},
{std::string(20, '9'), true},
{"-" + std::string(17, '9'), true},
{"-" + std::string(18, '9'), true},
{"-" + std::string(19, '9'), true},
{"-" + std::string(20, '9'), true},
// 64-bit boundaries
{"9223372036854775807", true}, // INT64_MAX
{"-9223372036854775808", true}, // INT64_MIN
{"18446744073709551615", true}, // UINT64_MAX
{"18446744073709551616", true}, // UINT64_MAX + 1 (overflows uint64_t, finite double)
// the 28-digit example from the issue: overflows uint64_t
// but is finite as a double, so the scanner reclassifies
// it to value_float and it is accepted
{"9999999999999999999999999999", true},
// huge digit-only integers that overflow even a double -> rejected
{std::string(309, '9'), false},
{std::string(400, '9'), false},
{"1" + std::string(400, '0'), false},
// 1e999 / 1e400 style overflow -> rejected
{"1e999", false},
{"1e400", false},
{"-1e999", false},
{"1E999", false},
// values straddling DBL_MAX
{"1.7976931348623157e308", true}, // <= DBL_MAX, finite
{"1.7976931348623159e308", false}, // > DBL_MAX, overflows to inf
// a mix of other valid/invalid numeric syntax
{"3.14159", true},
{"-0.0", true},
{"1.0e10", true},
{"01", false},
{"-", false},
{"1.", false},
{"1e", false},
{"+1", false},
};
for (const auto& c : cases)
{
const std::string& number = c.first;
const bool expected = c.second;
CAPTURE(number)
CAPTURE(expected)
// accept() takes the fast path (skips conversion when possible)
CHECK(json::accept(number) == expected);
// parse() always performs the full conversion; it must agree
json j;
CHECK_NOTHROW(json::parser(nlohmann::detail::input_adapter(number), nullptr, false).parse(true, j));
CHECK(!j.is_discarded() == expected);
// wrap in an array so get_token() is exercised beyond the
// very first (constructor-time) scan as well
const std::string wrapped = "[" + number + "," + number + "]";
CHECK(json::accept(wrapped) == expected);
}
}
}
}
@@ -1482,62 +1394,6 @@ TEST_CASE("parser class")
CHECK(accept_helper("\"\\uD80C\\uFFFF\"") == false);
}
SECTION("issue #5412 - whitespace skipping bookkeeping (compact vs. pretty-printed)")
{
// lexer::skip_whitespace() reads its first character with get() (to
// honor a possibly pending unget() from the previous token) and every
// further whitespace character with get_ignoring_pending_unget() (a
// get() variant that skips the then-always-false next_unget check).
// This must not change the reported byte offset, line, or column of
// a syntax error, even when a long run of whitespace containing
// multiple newlines is skipped beforehand (as with pretty-printed
// input). The expected values below were captured from the
// unmodified do-while(get()) loop, so any regression that miscounts
// characters or newlines while skipping whitespace changes them.
const auto check_error = [](const std::string & input, std::size_t expected_byte,
const std::string & expected_what)
{
CAPTURE(input)
try
{
json _ = json::parse(input);
FAIL_CHECK("expected a parse_error, but parsing succeeded");
}
catch (const json::parse_error& e)
{
CHECK(e.byte == expected_byte);
CHECK(std::string(e.what()) == expected_what);
}
};
// a nested document, serialized both compactly and pretty-printed
// (dump(4)), each truncated right before the final closing '}' so
// that the parser hits EOF after skipping all of the (in the
// pretty-printed case, substantial) indentation whitespace
const json doc =
{
{"a", 1},
{"b", json::array({true, false, nullptr, "x"})},
{"c", json::object({{"d", 3.14}, {"e", json::array({1, 2, 3})}})}
};
const std::string compact = doc.dump();
const std::string pretty = doc.dump(4);
check_error(compact.substr(0, compact.size() - 1), 60,
"[json.exception.parse_error.101] parse error at line 1, column 60: syntax error while parsing object - unexpected end of input; expected '}'");
check_error(pretty.substr(0, pretty.size() - 1), 193,
"[json.exception.parse_error.101] parse error at line 17, column 1: syntax error while parsing object - unexpected end of input; expected '}'");
// an invalid token appearing after several indented, multi-line
// whitespace runs vs. the same document without any of that
// whitespace
check_error("{\n \"a\": 1,\n \"b\": [\n true,\n false\n ],\n \"c\": @\n}", 70,
"[json.exception.parse_error.101] parse error at line 7, column 10: syntax error while parsing value - invalid literal; last read: '\"c\": @'");
check_error("{\"a\":1,\"b\":[true,false],\"c\":@}", 29,
"[json.exception.parse_error.101] parse error at line 1, column 29: syntax error while parsing value - invalid literal; last read: '\"c\":@'");
}
SECTION("tests found by mutate++")
{
// test case to make sure no comma precedes the first key
+2 -2
View File
@@ -304,8 +304,8 @@ TEST_CASE("Unicode (3/5)" * doctest::skip())
{
for (int byte4 = 0x00; byte4 <= 0xFF; ++byte4)
{
// skip fourth second byte
if (0x80 <= byte3 && byte3 <= 0xBF)
// skip correct fourth byte
if (0x80 <= byte4 && byte4 <= 0xBF)
{
continue;
}
+1 -1
View File
@@ -305,7 +305,7 @@ TEST_CASE("Unicode (4/5)" * doctest::skip())
for (int byte4 = 0x00; byte4 <= 0xFF; ++byte4)
{
// skip correct fourth byte
if (0x80 <= byte3 && byte3 <= 0xBF)
if (0x80 <= byte4 && byte4 <= 0xBF)
{
continue;
}
+1 -1
View File
@@ -305,7 +305,7 @@ TEST_CASE("Unicode (5/5)" * doctest::skip())
for (int byte4 = 0x00; byte4 <= 0xFF; ++byte4)
{
// skip correct fourth byte
if (0x80 <= byte3 && byte3 <= 0xBF)
if (0x80 <= byte4 && byte4 <= 0xBF)
{
continue;
}