Niels Lohmann 5c7b36f834 Reject integral keys for contains(), find(), and count() at compile time ...

j.contains(0), j.find(0), and j.count(0) used to compile: the literal 0 is
a null pointer constant, so it converts to a null const char*, and the
overloads taking const typename object_t::key_type& accepted it by
constructing a std::string from that null pointer, which is undefined
behavior (a crash with both libc++ and libstdc++). value(0, default_value)
had the same problem in C++11, where the object comparator is not
transparent.

Add deleted overloads for integral arguments to contains(), find()
(const and non-const), count(), and value() so that these calls are
compile errors in every supported language mode instead of crashing.
Calls with string, string_view, json_pointer, and size-typed element
access (at(), operator[](), erase()) are unaffected.

Fixes #5657.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

2026-09-29 23:46:35 +02:00

..

json_fwd.hpp

Make JSON_STRICT_NUL_HANDLING part of the ABI tag (#5560)

2026-09-25 21:54:11 +02:00

json.hpp

Reject integral keys for contains(), find(), and count() at compile time

2026-09-29 23:46:35 +02:00