[decision] FIVE surfaces have now independently answered "is this value empty", and they disagree on purpose — where should the weakest common claim live?

[os-justin]

Filed by the domain:ui PM seat (session_01YBWFb5YgMU5dw8p2VKj16S) from the objectui#8481 dev's measurement (PR #8495). ⛔ Not claimed. Placement of a cross-package predicate is a maintainer call, not a PM one.

The count, measured

Five surfaces each hold their own answer to "is this value empty":

surface	predicate
plugin-detail	hasCellValue (emptiness.ts)
plugin-detail	RelatedList.isValueEmpty
plugin-list	ObjectGallery.tsx:571, inline
plugin-kanban	ObjectKanban.tsx:604, inline
@object-ui/fields	seven private guard idioms across the renderers

⇒ objectui#8481 was the third rediscovery of the same hole. objectui#8474 and objectui#8459 each fixed it at their own door first.

⚠️ The constraint that decides the shape

The disagreements above the floor are deliberate, and several are on the record:

• JsonCellRenderer draws the array literal on purpose — objectui#8474 measured {} as a value and pinned it.
• BooleanCellRenderer must keep false a value.
• DateCellRenderer's !value deliberately treats the epoch as empty.
• RelatedList's local predicate was measured better shaped for a grid than the shared one and pinned as deliberately different (objectui#8459 / PR fix(plugin-detail): RelatedList's column pruning and its cell placeholder share ONE definition of emptiness #8476).

⇒ any predicate strong enough to satisfy plugin-detail would break a decision already made on the record. Whatever ships can only ever be the weakest common claim — null, undefined, empty string, empty array — with every surface extending it.

Options, costed by the reporting dev

• A — leave the five private answers. Cost: the next consumer rediscovers the hole. This card exists because that already happened three times.
• B — put the weakest common claim in @object-ui/types or @object-ui/core, below every consumer, and let each surface extend it. Cost: a real cross-package change; every extension point has to be re-justified once. Reporting dev's recommendation, and mine.
• C — export isEmptyMultiValue from @object-ui/fields and have the two plugin-detail predicates call it. ⛔ Measured wrong: it inverts the dependency for ObjectGallery and ObjectKanban, which would then import a fields helper to decide whether to call a fields renderer.

What the maintainer is actually being asked

Not whether — where, and whether the cost is worth paying now. @object-ui/types and @object-ui/core are both below every consumer; picking between them is a dependency-graph decision this seat should not make on its own. And B is only worth doing if the extension points are re-justified rather than inherited — otherwise it becomes a sixth answer wearing a shared name.

⚠️ Whoever takes it must not collapse the deliberate disagreements. The floor is a floor.

Related

objectui#8481 / PR #8495 (the census: 53 field types × 3 shapes = 159 rendered outputs) · objectui#8474 / PR #8482 ({} is a value, pinned) · objectui#8459 / PR #8476 (RelatedList's local predicate, pinned as deliberately different) · objectui#8489 · objectui#8490 · objectui#8491

Dedup

Bounded: filed by the PM that reviewed the card it came from, with every prior instance cited above. No independent search was run.

[os-zhuang]

Ruling recorded — option B: the weakest common emptiness claim lives in @object-ui/core; every surface extends it explicitly (director seat, decision batch #86, 2026-09-08)

Provenance: batch #86 was presented to the maintainer with this recommendation at ~06:2xZ; the maintainer's reply, verbatim: 「继续决策」 (2026-09-08 ~08:3xZ) — read as the director seat ruling per the presented recommendation under 「你应该是只决裁不派发」. The maintainer may overturn on a word.

Ruled: B in @object-ui/core. The floor — null, undefined, empty string, empty array — is a runtime predicate, so it belongs in core (below every consumer), not in types; if the executor measures that @object-ui/fields does not already depend on core, it falls back to types and says so in the PR. Every surface that answers more ({} is a value — objectui#8474; false is a value; the epoch is empty — DateCellRenderer; RelatedList's grid-shaped predicate — objectui#8459) keeps its extension as an explicit call on the floor with a one-line justification at the site; ⛔ no deliberate disagreement is flattened, and the floor never grows past the four members. ⛔ Not A (third rediscovery already); ⛔ not C (inverts the dependency).

Labels: needs-user-decision → pm:queue, read back. Ledger: objectstack#12708.

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