The shell pipeline's options were still accepted, so `sync -h` listed five
entries reading only "retired". The scripts themselves are gone, so the
migration hints have outlived what they pointed away from.
Each command now states what it does and which options are required, instead
of the flag package's bare "Usage of sync:". The top-level help lists the exit
codes, including the new 4, and says which one is worth retrying — that is the
part a driver script needs and the only place it was written down outside the
README.
Also fixes a real defect in the flag help: a backquoted word in a usage string
is the flag package's placeholder syntax, so "as `tdl dl --takeout` did"
rendered the option as "-takeout tdl dl --takeout". Backquotes are now used
deliberately, giving -c CHAT, -r REMOTE:PATH, -m SIZE and friends.
Phases 4 through 6: the two legs and the command that joins them.
Downloads go to <name>.part and are renamed only once complete, so a file
without the suffix is always whole. That is what lets the upload leg treat
"exists" as "finished" — the property run.sh could only approximate with a
filename convention plus an age guard, because it could not see inside tdl.
Every finished file is checked against the size Telegram reported, and that
check rather than the error is the authoritative signal. core's downloader logs
a failed transfer and returns nil, and its completion callback is deferred on
that named return, so a failure arrives indistinguishable from a success.
Trusting it would promote a truncated file and archive it as complete.
The disk cap is a semaphore over bytes. A download reserves its own size before
starting and releases it only after the upload confirms, so a slow remote
stalls downloads by itself. Blocking the iterator is safe because the
downloader calls it from its dispatch loop while workers run in a group, so a
blocked iterator never stops the uploads that free the space. Gone with it: the
du polling, the SIGSTOP and SIGCONT suspension, the min-age guard, the
temp-file filter and the sweep-failure counter.
A cap smaller than the largest file is refused up front. The semaphore could
never admit it, and a run blocked on a file it can never start looks exactly
like a stalled remote.
Uploads re-state each object to prove its size before the local copy is gone,
closing a gap where a truncated upload was only noticed by a later verify.
The destination is created before the chat is read. It is also the credentials
check, and doing it first means a bad destination fails in seconds rather than
after a full history walk.
One invocation converges: each item is checked against the index immediately
before download, so there are no passes and re-running is the resume path.
Options that no longer exist say what replaced them instead of failing as
unknown flags.
Verified end to end against the live chat and a scratch remote path: two files
downloaded, uploaded, confirmed present at the right size, staging left empty.
tiennm99