fix(signals): a projection's leaf companions die with the projection; latest() of a dead leaf creates none (spec O5) - #3505
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… latest() of a dead leaf creates none (spec O5, INV-4) Disposing a store whose async source was mid-refetch left the latest() shadow of a leaf orphaned: never derived (its compute read through the projection in flight, the backfilled override stood in), its override dropped at the settle, NotReady/uninitialized forever against a leaf whose committed value differed — INV-4 at the next quiescence. Externally coherent (latest() fell back to the committed value), but a companion outliving its source, which is what INV-9's rationale forbids. The disposal snap covered the disposed computed's own companions only; a projection's leaves hang off the firewall, not the child chain. Two parts: - disposeChildren(self) snaps the companions of the firewall's _companionChildren (the set markFirewallChildCompanions maintains, #3038); snapCompanionsToState retires a shadow whose owner's firewall is disposed — a disposed shadow reads as absent, a later read recreates it from the committed view. The isPending signal snaps as the owner's does. - latestRead of a leaf whose firewall is disposed serves the committed value and creates no shadow: a boundary's content re-running after the teardown recreated one that no teardown would ever retire. That recreated shadow was the posture matrix's actual trigger. Surfaced once #3495 stopped leaking parked transactions, which had kept `transitions.size > 0` and masked every __TEST__ quiescence check in the matrix. All 621 matrix cells run with zero invariant violations; the two excluded cells are back. Pin flipped from it.fails and extended with the post-disposal read. +104 B minified (owner.ts, core floor); five brotli caps +13…+43 B. Co-authored-by: Claude via Cursor <noreply@cursor.com> Co-authored-by: Cursor <cursoragent@cursor.com>
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Closes spec O5 (the INV-4 surfaced by #3495).
Bug
Disposing a store whose async source was mid-refetch left the
latest()shadow of a leaf orphaned. The shadow had never derived a value — its compute reads through the projection in flight (NotReady), so the backfilled override stood in — and the settle after disposal dropped the override, leaving it NotReady/uninitialized forever against a leaf whose committed value differed. The__TEST__quiescence invariant INV-4 fired on the next flush. Externally coherent (latest()fell back to the committed value), but a companion outliving its source is exactly what INV-9's rationale forbids.Why it was invisible until now: the posture matrix had been leaking parked transactions (the bug #3495 fixed), which kept
transitions.size > 0and silenced every quiescence check for the rest of each run.Fix — two parts, found in two rounds
disposeChildren(self)now snaps the companions of the firewall's_companionChildren(the setmarkFirewallChildCompanionsalready maintains, 2.0.0-rc.1 | flush cost scales with total materialized store signals (async-companion walk in sync-only apps) #3038), andsnapCompanionsToStatedisposes a shadow whose owner's firewall is disposed — a disposed shadow reads as absent, so a later read recreates it from the committed view. The isPending signal snaps as the owner's own does.owner.tsgets one line; the logic lives inverdict.ts, outside the core floor.latest()of a dead leaf creates nothing. With (1) alone the standalone pin passed but the matrix still tripped: tagging shadows by creating cell showed the orphan was a second shadow, created bylatest()inside boundary content re-running after the projection's teardown — nothing would ever retire it.latestReadnow serves the committed value for a leaf whose firewall is disposed (a read of a disposed node freezes at its last commit, 2.0.0-rc.1 | signal source function revaluates when derived from a component prop - on component cleanup #3024).Gate
it.fails, extended with the post-disposal read (tests/inv4-projection-dispose-shadow.test.ts).owner.ts, core floor); five brotli caps +13…+43 B.