session_over_one_router asserted that a latest subscriber must drop
snapshots. bus-v1 section 7 says a latest subscription replaces an
undelivered value; it lets a consumer miss values, it does not oblige it
to. Under contention the publisher was slow enough that the renderer kept
up, saw all twenty snapshots and the test failed on conforming behaviour:
16 of 40 runs beside four busy loops, and 9 of 20 whole-crate runs.
The renderer is now held until the publisher's completion is observed
rather than until a timer expires, so the coalescing is forced instead of
raced for: the subscription keeps the one delivery in flight and one
replaceable queued value, and the renderer receives snapshots 1 and 20 of
20. The assertions are the guarantees that hold -- what arrives is in
publication order, the last value is the latest published, the stalled
spectator never refuses a publication or drops out of the fan-out, and
every snapshot the renderer missed is counted as a replacement to the
publisher at admission and to the renderer on delivery, so nothing is
lost silently.
Three more tests in the crate asserted the same kind of race:
- latest_replay_is_ordered_ahead_of_a_racing_publish demanded the
non-coalesced outcome of a race section 7 allows either way ("bounded
mode preserves that order, while latest mode may coalesce it"). It now
puts one racing publication to a bounded and a latest subscription at
once: bounded must deliver the replay and then the publication, and the
latest branch is chosen by that publication's own replaced count.
- collection_waits_for_every_retained_owner, and the two disconnect
cleanup tests beside it, read the store directory for the unlink that
follows the registry update outside the router lock. They use
settle_files, like every other unlink check in the suite.
- The demo example printed a root count taken before the producer's own
release had reached the router, so the line the guide quotes was a
race. It waits for the release, the same way it already waits for
collection; the printed output is unchanged.
Nothing under flybus/src is touched: no routing defect was found. The
conformance rows for the credit/queue split, the replaced count, the
replay ordering and the latest spectator that cannot refuse a publication
now cite what each rewritten test actually varies.
An independent review of 4f44894 accepted the audit with two required evidence
changes, neither of which needed a code change.
"Classification is not a topic-name heuristic" cited a lane-order test that
never varies a topic name. The row is now conforms-by-construction, naming the
four scheduler functions that read only the queue an item sits in, and
a_topic_named_like_a_notice_is_still_classified_as_topic_data publishes on
topics called call.failed, route.removed and subscription.closed and asserts
each arrives as a topic.message delivery with its payload intact.
"A latest subscriber never causes BACKPRESSURE" cited a bounded-mode test and
the ignored measurement. a_latest_subscriber_never_refuses_a_publication floods
one unconsumed latest slot with 100 publications of 60 KB, six times the
per-client bounded byte pool, and asserts none is refused, 98 coalesce, the
queue stays at one and the credit never comes back. That row also underwrites
the byte-budget deviation and the first contradiction.
Both tests run over both transports.
The coordinator resolved both contradictions in the spec rather than the code,
so bus-v1 carries them as dated amendments with one line of reason each: the
section 9 table row becomes "Per-client ordinary bounded queued envelope bytes"
with a new "Latest subscription slots | subscriptions x 64 KiB" row, and the
section 2 sketch drops the budget argument and shows the deadline at the caller.
With the amended wording the byte-budget row conforms, so the report's counts
are 178 / 9 / 1 fixed / 7, and the crate README's differences 4 and 8 say they
no longer differ.
bus-conformance.md audits the flybus crate against bus-v1 sections 2 to 11, one
row per normative sentence: requirement, status, code location, the test that
proves it. 195 rows, 177 conforming, 10 deviating with the sentence that allows
each, 1 must-fix (the teardown starvation, fixed in this branch) and 7 not
implemented with an owner named. It also maps every BUS-01/02/03 acceptance
bullet to its test, reconciles all ten of the crate's own differences from the
draft, records the frame measurement with the reasons it is not a capacity
claim, and lists the two contradictions inside the draft it will not guess at:
the per-client queued byte budget against the latest-mode guarantee, and
section 2's call budget against section 6's client-owned deadline. Neither
changed any code.
bus-v1 gains section 12: dated amendments for the three error codes the
implementation needs and the draft left unnamed (CONFLICT, NO_TOPIC,
ARTIFACT_MISMATCH), one line of reason each, and for the one operation it adds
(rpc.responder.release), which is how bounded call correlation ends when a
handler keeps reply authority after releasing the request delivery. Section 9's
error list is inclusive, and section 4 already provides for a digest change.
The crate README points at the report, carries the new measurement summary in
place of the old numbers, and describes the two new test files; the design index
and the flybus index point at the report too.
