Swap diagnostic positions in basic_json::swap()

basic_json::swap() (and the friend swap() that forwards to it) only
exchanged m_data.m_type/m_data.m_value, leaving start_position/end_position
untouched under JSON_DIAGNOSTIC_POSITIONS. This is inconsistent with
copy-assignment's operator=(basic_json), which swaps positions as part of
its copy-and-swap implementation, so after swap(a, b) each value ended up
with the other value's content but its own original position.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann
2026-09-05 21:32:43 +02:00
parent 09b6b6b5ba
commit 8f5dbb56c5
4 changed files with 93 additions and 2 deletions
+6 -2
View File
@@ -34,10 +34,14 @@ void swap(typename binary_t::container_type& other);
```
1. Exchanges the contents of the JSON value with those of `other`. Does not invoke any move, copy, or swap operations on
individual elements. All iterators and references remain valid. The past-the-end iterator is invalidated.
individual elements. All iterators and references remain valid. The past-the-end iterator is invalidated. If macro
[`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) is defined to `#!cpp 1`, the
[`start_pos()`](start_pos.md)/[`end_pos()`](end_pos.md) diagnostic positions are exchanged along with the value.
2. Exchanges the contents of the JSON value from `left` with those of `right`. Does not invoke any move, copy, or swap
operations on individual elements. All iterators and references remain valid. The past-the-end iterator is
invalidated. Implemented as a friend function callable via ADL.
invalidated. Implemented as a friend function callable via ADL. If macro
[`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) is defined to `#!cpp 1`, the
[`start_pos()`](start_pos.md)/[`end_pos()`](end_pos.md) diagnostic positions are exchanged along with the value.
3. Exchanges the contents of a JSON array with those of `other`. Does not invoke any move, copy, or swap operations on
individual elements. All iterators and references remain valid. The past-the-end iterator is invalidated.
4. Exchanges the contents of a JSON object with those of `other`. Does not invoke any move, copy, or swap operations on