# zit 0.7.2

zit 0.7.2 closes the limit 0.7.1 named: a store no longer keeps a seed
that a peer sends it outside a seed announcement, so it can never serve
one on. The horizon draft states the rule.

This release is from trunk. Stores are unchanged from 0.7.1.

## A received seed is never stored

A seed is private to the clone that holds it, and an origin sends one
only under a `horizon-seed` announcement, which a clone keeps outside
its artifact store. 0.7.1 refused a pushed seed, but an artifact of the
same shape arriving on a clone, pull or sync was stored as an ordinary
control artifact. zit never derived tags from it, but it could serve it
to other peers.

Now every receive path drops an artifact that carries the store's seed
label (`zit-seed`) or a `horizon-seed` binding card. The test is made on
the artifact's verified content when it is written, whether it arrived
in full or as a delta completed in a later round. A dropped artifact is
not counted among those received. An artifact sent as a delta against a
dropped one is stored in full. A control artifact under another label
and with no binding card is kept as before.

A zit origin writes pushed artifacts through the same path. It already
refuses a pushed seed before writing anything, and it drops a pushed
delta whose base it lacks, so a seed completed by a later push never
reaches it. The check stands behind both.

zit keeps no record of what it dropped, so a peer that keeps offering
one is asked for it again on the next exchange, and it is dropped again.

## The horizon draft

`docs/rfcs/draft-fossil-horizon-00.txt` states the receive rule in
Section 5.2.3. It also states that a store which keeps a delta whose
base it lacks must not announce or serve that delta while it cannot be
expanded. Appendix C records the change.

## Test harness

The Fossil round-trip script stopped the subshell that started `zit
serve`, not the server, so each run left a server listening. It now
stops the server. Smoke scenarios that start a server on a fresh
loopback port try another port when the first is taken before the
server binds.

## Compatibility

Stores are unchanged from 0.7.1, in both directions. A store written by
an earlier release may hold a seed-shaped artifact. zit still skips it
when deriving, and a peer running 0.7.2 drops it on receipt.

On the wire nothing changes.

## Qualification

The release manifest records native qualification against the exact tagged
source archive on macOS ARM64, Linux x86-64 and Linux ARM64, using the pinned
Zig 0.17.0 toolchain. Publication is gated on unit and end-to-end tests, Git
differentials, deterministic simulation, seeded fuzzing, and Fossil
interoperability checks on every distributed target.

For the basis of the conformance claim, see
[the 0.1.0 release notes](RELEASE-NOTES-0.1.0.md).