Fieldtest spec_gap (#335): the timestamp a fold's one summary row
carries was undocumented. Ratified as-is (derived decision, minuted on
the issue): the row is emitted at finalize and stamped with the instant
of the last contributing (warm) value (TapFold::last_ts) — first alone
pins the first contributing instant, and min/max deliberately do not
carry the extremum's instant (a whole-window row privileges no interior
instant, and the extremum ts would cost extra state for no consumer).
The issue's initial finalize-ts reading (and the first draft of this
ratification) was refuted in review against tap_fold.rs: a tap that
goes cold before run end stamps the last WARM eval's instant, not the
run-end instant — observationally identical only while the tap stays
warm to the end, which is what the fieldtest fixtures did. Correction
minuted on the issue.
Recorded in C27's Current state and the glossary tap-plan paragraph;
the fold-registry roster doc lines state it on the surface itself
(sibling commit).
closes#335
claude
98342246f6