mirror of
https://github.com/nlohmann/json.git
synced 2026-10-03 13:10:33 +00:00
Niels Lohmann
f30ee4bcfe
array_index(), contains() and get_checked_or_null() each re-implemented the RFC 6901 array-index rules and the size_type range check: array_index() does the canonical parse and throws; contains() (which must not throw, #5395) re-validates every digit by hand and runs its own strtoull/ERANGE check before calling array_index() anyway, parsing every array token twice; get_checked_or_null() wraps array_index() in JSON_TRY/ JSON_INTERNAL_CATCH (detail::out_of_range&) to turn an unrepresentable index into "not found". Add a single private, noexcept parse_array_index(s, idx) returning an array_index_status (ok / leading_zero / not_a_number / unresolved / exceeds_size_type). array_index() becomes a thin wrapper mapping each status to the existing parse_error.106/109 or out_of_range.404/410; contains() and get_checked_or_null() switch on the status directly. This removes contains()'s digit-validation loop and its second strtoull call, and get_checked_or_null()'s JSON_TRY/JSON_INTERNAL_CATCH. Bugfix as a consequence: get_checked_or_null()'s JSON_TRY/ JSON_INTERNAL_CATCH was dead code under JSON_NOEXCEPTION (JSON_TRY expands to "if(true)" and the catch to "if(false)", so JSON_THROW's std::abort() ran unconditionally), meaning value() and contains() would abort instead of returning the default/false for an out-of-range-sized or oversized array index when exceptions are disabled (#5672). Switching on parse_array_index()'s return value instead of relying on an actual throw/catch fixes this: get_checked_or_null() now returns nullptr for array_index_status::unresolved/exceeds_size_type in every build configuration, and still calls JSON_THROW (aborting under JSON_NOEXCEPTION, as before) only for a malformed index (leading_zero/not_a_number), matching its documented @throw list. All existing error ids, messages and diagnostic paths are unchanged; a few reference tokens that used to fail contains()'s manual per-character validation (e.g. "1a") now fail via array_index_status::unresolved instead, with no observable difference since contains() only returns bool. Adds regression tests to unit-element_access2.cpp's "access on array type" section covering value() with an index that exceeds size_type and one with a trailing non-digit, both of which must yield the default value rather than abort/throw. Public API: no change. Overlaps #5700, #5614 and #5692, which touch the contains() and get_checked_or_null() array hunks; this change replaces those hunks with calls into the new shared parser, so a rebase will need to re-apply their token-handling changes (e.g. the empty-token case) on top of the switch statements here. Signed-off-by: Niels Lohmann <mail@nlohmann.me> #5708 item 4