Resolve a relative --compare-dest/--copy-dest/--link-dest DIR against the
destination directory and append the file's transfer-relative name, as
rsync 3.4.1 does, instead of appending FastSync's source-mirrored wire
path (the historical spelling stays as a fallback for existing layouts).
Stop inheriting the ordinary delta engine's 16 KiB minimum and 10x size
ratio in the -y/--fuzzy candidate search: rsync's find_fuzzy has no
delta-size gate, so an oversized or sub-16-KiB sibling is now reused.
The ordinary delta path's bounds are unchanged.
Probe shows the candidate choice is observable only as --stats bandwidth
counters (tree/exit always identical). FastSync already uses rsync's
fuzzy_distance/find_filename_suffix name heuristic; the residual is the
narrower delta eligibility window (>=16 KiB, <=10x) vs rsync's wider one.
Row -> caveat; tally 116/14/27.
Each row's exact residual reproduced against rsync 3.4.1:
- basis dirs (--compare/copy/link-dest): FastSync xxHash-verifies a basis hit
while rsync --size-only installs the wrong same-size basis content.
- --delay-updates: the fixed .fastsync-stage name wipes an unrelated
destination entry of that name even without --delete; rsync leaves it.
- --fuzzy: deterministic name/size heuristic (10x window), not rsync's matcher.
- --dry-run: would-delete report over-reports the updated file and an
excluded-but-protected extra, and ordering differs.
Docs: RSYNC_COMPAT tally 109/16/31; HANDOFF item 9. clang-format + cppcheck +
ASan + full suite clean.
Accept the full rsync 3.4.1 --info (backup, del, flist, mount, nonreg,
progress, remove, symsafe) and --debug (acl, backup, bind, chdir, connect,
cmd, del, deltasum, dup, exit, filter, flist, fuzzy, genr, hash, hlink,
iconv, nstr, own, recv, send, time) vocabularies, plus the historical
syms/hl/owner aliases, with level suffixes. Categories FastSync already
emits (copy/name/misc/skip/stats and io/proto/pack/util) still set their
log flags; the rest are accepted but silent. Unknown names remain
rejected by name, matching rsync. Update the CLI unit tests and the
rsync-parity integration tests (previously they required del/filter to be
rejected).
- Assert FastSync's sparse/preallocate block accounting matches rsync 3.4.1
for a hole file (preallocate wins over sparse, exactly like rsync).
- Assert --ignore-existing is answered by the receiver before the sender
transmits the payload (CountingProxy wire volume near-zero).
- CountingProxy.run gains a bounded join_timeout so tests that only need the
client->server count do not wait for the server's idle socket.
- Fix the stale protocol 2.24.0 comment in test_config.c (golden is 2.26.0).
TapTap