Review follow-ups on the --fuzzy candidate scan:
- Allocate the two DP rows once per directory scan instead of once per
candidate (4096-entry directories no longer do thousands of malloc pairs).
- Pre-prune before the DP with two cheap lower bounds on the edit distance:
the name length gap and the count of characters of one basename absent from
the other; a candidate whose gate (distance*2 <= longer) already fails on
the max of those bounds is skipped without running the DP.
- Trim the common prefix and non-overlapping common suffix before the DP so
it only runs over the differing middles.
- Note that the 4096 readdir cap bounds iterations, not per-entry DP cost,
and that the seen set is filesystem-order dependent (winner stays
deterministic via the total comparator).
- Open the chosen candidate with O_NONBLOCK so a name raced to a FIFO cannot
block the receive thread forever in open(2); the existing fstat S_ISREG gate
still rejects non-regular files. (The pre-existing basis_open_regular has
the same latent FIFO pattern and is intentionally left unchanged.)
- Free old_data in receive_delta_file's defensive NULL guard.
TapTap
be37a509a5