Bug 1 (crash): jay_merge_delete iterated _new.items() while _old (which
aliases _new sub-dicts due to jay_diff_rev's side-effect writes) was being
mutated. Fixed by snapshotting with list(_new.items()) before iteration.
Bug 2 (wrong round-trip): When new has an empty dict {} at a location where
old had a non-empty dict, jay_merge_delete incorrectly pruned the now-empty
parent key. Root cause: jay_diff_del stored the full old sub-dict in the
delete delta for both "key absent from new" and "key present but empty in
new", making them indistinguishable at merge time.
Fix: jay_diff_del is now a standalone recursive function that stores None
for dict keys entirely absent from new (sentinel for "delete entire key")
vs a sub-dict of specific sub-keys for partial deletions. jay_merge_delete
no longer prunes empty dicts; None (or any non-dict value) in the delta is
the explicit signal to remove the parent key.
Also adds:
- tests/data/ — copy of 25 real JSON log files for integration testing
- tests/test_jay_diff_real_data.py — 2028 parametrised round-trip tests
over 675 real vehicle snapshots; exposed and confirmed both bugs above
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
jensandClaude Sonnet 4.6
c8de234423