The subscriber marked a notification intent as seen before the monotonic
sequence guard ran. A late packet was then dropped by that guard with its
intent already burned, so the genuine retry of a notification this
subscriber had never delivered was mistaken for a replay and dropped too.
Identity comparison stays ahead of the sequence guard -- a duplicate must
not consume a sequence number -- but the bookkeeping write moves behind
it, so "seen" means "accepted" rather than "arrived".
An intent that cannot yield a stable identity (not an object, or holding
an unhashable value) is now refused instead of raising out of the
callback: a paho callback that raises takes the network loop down for
every job that subscriber is watching.
Six regressions; three of them fail on the unfixed tree, and one drives
a real notifier retry through the real consumer with no hand-built
payload. Full suite: 732 passed, no skips.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UrDNJkHmm18uu7n7JwV5Qd
GodopuandClaude Opus 5
8d7e010f9f