Niels Lohmann 03784997bf Avoid redundant lookups in diff()'s object-order tracking ...

The previous fix for ordered_json member order re-derived common-key
order and suffix information with extra target.find()/source.find()
calls layered on top of the pre-existing removed/added-key passes,
instead of reusing those same passes. This roughly tripled the number
of map lookups per diff() call for every object, including plain
`json`, where the reordering path is never taken.

Piggyback the order tracking (and the "add" op construction for new
keys) onto the two passes the algorithm already needs to detect
removed/added keys, and walk the fast path's recursion in lockstep
with the precomputed common-key list instead of re-querying `target`.
This restores diff() to its pre-existing lookup count; benchmarked at
n=1000 keys, ordered_json::diff() was roughly 2x slower than baseline
before this change and is back within noise of baseline after it.

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

2026-09-05 17:05:48 +02:00

..

json_fwd.hpp

📄 adjust year (#5044)

2026-01-01 20:00:39 +01:00

json.hpp

Avoid redundant lookups in diff()'s object-order tracking

2026-09-05 17:05:48 +02:00