P2 (hardening) of the retry audit, closing the report's remaining findings.
- Lease fencing. `lease_next` now stamps a random `lease_token`, and every
write-back a worker makes (the 30s heartbeat, `delete_row`, `reschedule`,
`mark_done`) is guarded by it. A lease that expired while its holder was
stalled and was then re-leased used to let *both* holders write the same row:
one duplicated the send, the other silently discarded the new holder's retry
(a 0-row update was not even logged). Now a worker that no longer holds the
lease drops its attempt at the next heartbeat and writes nothing. Reaching
existing databases needed a migration chain, which `db.rs` had been
pre-committed to: `MIGRATIONS` + `migrate` track `PRAGMA user_version`, with
`schema_init` as the version-0 baseline. Verified on a database created
before this change: user_version 0 -> 1, column added, rows intact.
- Dead-letter notifications no longer mislabel an unparsable payload. A row
whose payload no longer deserializes as a `Task` (an older version's shape,
corruption) used to skip the cache invalidation *and* report "Forward failed
permanently" for a send task, because both were derived from the parsed
value. The identity now comes off the raw JSON, so the stale link-cache entry
is dropped and the message names the post.
- Temp files are marked and swept. Every temp file/dir the project creates now
carries `x_media::TEMP_FILE_PREFIX`, and startup removes entries with that
prefix older than an hour — a killed process leaves its downloads (up to
hundreds of MB) behind because no destructor runs, and the age gate keeps the
sweep away from a second instance's in-flight files. Verified live: the log
reports the sweep, an aged leftover goes, a fresh prefixed file and an
unrelated file stay.
YoursFunny