Niels Lohmann 01b53c8c15 Keep JSON_DIAGNOSTICS parent pointers of ordered_json members after erase() and update() (#5552) ...

* Keep JSON_DIAGNOSTICS parent pointers of ordered_json members after erase() and update()

ordered_json stores its members in a vector, and two operations moved
members without restoring their parent pointers afterwards:

- ordered_map::erase() re-constructs every member after the erased one in
  place. The basic_json move constructor leaves m_parent at nullptr, and
  none of the object branches of basic_json::erase() (by key, iterator, or
  iterator range) called set_parents(). This also affected merge_patch()
  with a null member and patch() with a remove operation.
- update() only set the parent pointer of the inserted member. Adding a key
  can reallocate the vector, which copies all other members and leaves
  their m_parent at nullptr. The set_parents() call added for #4813 only
  repaired this for the nested object of a merge, not for the target.

The next assert_invariant() on such an object (for instance, when copying
it) aborted, and diagnostic messages lost the path prefix above the moved
member. std::map-based json was not affected, because its nodes do not
move.

Erasing from an ordered_map object now calls set_parents(), and update()
uses set_parent(), which already refreshes all members for vector-based
objects. This makes the #4813 workaround redundant.

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

* Account for JSON_DIAGNOSTIC_POSITIONS in the ordered_json parent-pointer test

The merge_patch() case parses its input, so with JSON_DIAGNOSTIC_POSITIONS
the exception message also carries the byte range of the parsed value.

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

* Silence clang-tidy for the intentional copy in the ordered_json parent-pointer test

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

* Keep parent pointers when update() merges past its descent bound

The iterative path of update() only set the parent pointer of the member
it inserted, like the recursive one did before. It now uses set_parent()
too, so ordered_json members that move when a nested object grows keep
their parents, and the set_parents() calls that patched this up after
each nested merge are gone.

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

---------

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

2026-09-25 08:29:36 +02:00

..

nlohmann

Keep JSON_DIAGNOSTICS parent pointers of ordered_json members after erase() and update() (#5552)

2026-09-25 08:29:36 +02:00