Two review findings from @karthik-indla on this PR.
_drain returned (0, True) on any read failure, so a claim nothing was posted
from counted as fully delivered. flush() then carried on to the next claim as
though this one had arrived, and the single signal that says the run went badly
never fired. The two cases are now separated: undecodable content is still
quarantined and reported delivered, because there is nothing left to send and
the rest of the run should continue, while an OSError leaves the file exactly
where it is and reports undelivered. Quarantining there would discard events
over a transient filesystem error, and nothing ever re-globs .corrupt.
Retries had no time backoff. _release_claim backdated straight to
immediately-reclaimable, so two senders meeting one momentary failure could walk
a batch from attempt 0 to the limit within seconds and discard it, when a retry
a minute later would have delivered. Releases now carry a cooldown that grows
with the attempts already spent, clamped so the mtime never lands in the future
and reads as a live lease.
Four tests: an unreadable batch is neither delivered nor quarantined,
undecodable content still is quarantined so one torn file cannot block every
later claim, and attempts cannot be burned without waiting. The expiry test now
ages the file between flushes, which is the wall time a real retry waits.
Claude-Session: https://claude.ai/code/session_01C7tEmH86HAr7GoAAKCEHZb
Saket Aryan
40287f6f04