Niels LohmannandClaude Sonnet 5 633eef8494 fix: treat a NUL byte in the input as an ordinary byte, not EOF ...

The lexer's token dispatch had `case '\0':` fall through to the same
`end_of_input` handling as the real end-of-file sentinel, with a comment
claiming the NUL case was "needed when parsing from string literals".
That rationale no longer holds: input_adapter(const char*) already uses
strlen() to compute its range, so it never hands the lexer a trailing
NUL, and the const-char* overload is the only "string literal" path the
comment could be referring to. In practice, `case '\0':` only ever fired
on a genuine embedded or trailing NUL byte in real input data (e.g. a
std::string with '\0' appended), which was then silently swallowed as if
it were EOF instead of producing the parse_error.101 any other
unexpected byte gets. Two more spots in the comment-skipping logic had
the same NUL-as-EOF idiom, stopping a `//` or `/* */` comment scan early
at an embedded NUL instead of continuing to the real terminator.

Removing all three still left one real regression: input_adapter's
T(&array)[N] overload (used for a string literal like
json::parse("123"), as opposed to a decayed const char* pointer) passes
the array's full extent through unchanged, trailing '\0' included. That
path was relying on the lexer's old NUL-as-EOF behavior to make ordinary
literal parsing work at all. It now gets its own strlen()-like handling
for char arrays specifically: a single trailing NUL terminator is
excluded, mirroring the pointer overload, while non-char arrays (e.g.
uint8_t buffers for binary formats) are left untouched since a trailing
zero byte there may be data.

Also updates a few existing tests that (mostly incidentally) depended on
a trailing NUL being swallowed - std::array<uint8_t, 5>{"true"} left the
5th element zero-initialized - and adds an FAQ entry.

Signed-off-by: Niels Lohmann <niels.lohmann@gmail.com>
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01N4RQ1Ahan5YAGbnAQGjZTY

2026-09-15 07:12:35 +00:00

..

json_fwd.hpp

📄 adjust year (#5044)

2026-01-01 20:00:39 +01:00

json.hpp

fix: treat a NUL byte in the input as an ordinary byte, not EOF

2026-09-15 07:12:35 +00:00