2.0.0-rc Async memo chain publishes a stale result alongside a newer signal value

[GabbeV]

Describe the bug

Updating a signal again while its async memo chain is pending can make one JSX expression show mismatched values. The repro displays 0 / 0 → 2 / 1 → 2 / 2, even though both memos just forward the signal's value.

Your Example Website or App

https://s.olid.uk/id/iP5gJf0HRSGuTKCEGVKrLA

Steps to Reproduce the Bug or Issue

1. Wait for 0 / 0 to appear.
2. Click Run.
3. See 2 / 1 appear before settling at 2 / 2.

Expected behavior

Both numbers should always match.

Screenshots or Videos

No response

Platform

• OS: Windows
• Browser: Firefox

Additional context

Reproduces on next at f8b40b7 and #3337 at 20f3143.

Making either memo synchronous removes the mismatch.

[ryansolid]

Reproduced at the signals level and fixed in #3381 — thanks for the clean reproduction.

Root cause: setCount(2) restarts a while b's first flight (b1, computed from a=1) is still in the air. That only changes a's status, not yet its value, so b is marked pending on a by propagation with b1 still current — nothing supersedes it. When b1 lands, the landing's status clear wiped all of b's pending sources, including a. b's staged 1 woke the text, which saw nothing pending; the transaction's reporter for a found nothing blocking below it and committed count=2 beside b=1.

Fix: a landing now retires only the node's own pending entry. b stays pending on a; the landed value is written and held, and either a's settle releases it or a's value change re-asks b. Your timeline now publishes 0 / 0 → 2 / 2.

— Claude via Cursor

[ryansolid]

Fixed on next in d7cb456 (#3381), ships in the next RC. Root cause: when count=2 re-asked a while b's first flight was still up, b's landing cleared all of its pending sources, including the propagated entry for a, so the transaction found nothing blocking and committed count=2 beside the stale b=1. A landing now retires only the node's own entry (landStatus); b stays derivatively pending on a until a2 lands. Pinned in tests/async-chain-supersession.test.ts. Thanks for the precise reproductions — all four of this batch shared one shape.

— Claude via Cursor