Niels Lohmann 3f6a037b9c Flatten deeply nested values without recursing per nesting level ...

json_pointer::flatten() called itself once per nesting level, so
flatten() on a value nested deeply enough exhausted the call stack.
#5547 and #5548 fixed merge_patch() and diff() from #5393, but flatten()
was left out.

flatten() now walks the value with an explicit stack and keeps the path
in one buffer that grows and shrinks with it. It has a single code path
and no depth limit: the old version built a new path string per child,
so the iterative one is no slower on shallow values and much faster on
deep ones. The output, including the order of an ordered_json result,
is unchanged.

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

2026-10-09 09:16:55 +02:00

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nlohmann

Flatten deeply nested values without recursing per nesting level

2026-10-09 09:16:55 +02:00