[Decision] How does a filter say 「is empty」 on a multi-value field? A declared `$empty` operator, or reopen the empty-list refusal (ruling B on #20311, its third arm)

[objectstack-fleet]

Ruled: 5865693155 · letter A · 2026-09-28T07:49Z

This card carries the one question ruling B on #20311 left open: how the lowered filter spells the multi-value arm (null or []), and so where the per-type table is applied. #20311 keeps the implementation, and is pm:blocked on this card.

Parent: #20311 (ruled B, 5861435168). Derived from the in-flight dispatch on #20311 (claim 5864663193), whose dev stopped before code with premise_still_valid: false (report 5864899591). Filed by domain:spec seat 1 (session_01B3TqpoQbTAfG7G74GMDWNW, seat post #6017). Grade inherited from the parent: domain:spec · priority:p2 · area:records.

维护者速读

一句话问题:您裁定「为空」对多值字段(多选、标签、多值查找)= 空值或空列表。但今天平台的查询语言里没有任何写法能表达「这个列表是空的」:空列表放进等值条件会被一条更早的裁决(#19757 乙,5 天前)明令拒绝,也没有别的操作符能测它。所以裁决 B 的第三条臂无法按原计划写进协议。

为什么要您拍板:两条出路都改公开契约。一条是给查询语言新增一个操作符,另一条是推翻 #19757 的一部分。执行席不能自己选。

选项:

选项	做什么	客户可感知的后果
A(荐) 新增 $empty 操作符	查询语言多一个「是否为空」操作符。它的说明就是您裁的那张按类型展开的表。is_empty 不再需要知道字段类型,由真正执行查询的地方(数据库驱动等 8 处)按字段声明的类型展开。	已存视图里的「为空」不用改就对了。多值字段的「为空」第一次能用(今天报错)。代价:8 处执行面各实现一次,要分阶段落地(先让执行面认识新操作符,最后再切换翻译)。
B 翻译时带上字段类型	is_empty 在翻译成查询时就按类型展开;多值臂写成「等于空列表」。	必须重开 #19757 乙,为空列表开口子;SQL 系、内存驱动、公式求值器都要学会在 JSON 列上比较空列表(今天都拒绝或查不到);3 处服务端翻译口要改成传类型;已存的共享规则条件会把「当时的字段类型」冻结进去。
C 先做文本和空值两臂,多值臂另裁	只交付裁决 B 的三分之二。	多值字段的「为空」继续报错;若以后多值臂按 A 落地,C 这一半要返工。

业务含义直译:A 等于「在查询语言里正式有一个『为空』按钮,谁执行谁按字段类型解释」。Notion 数据库查询、ServiceNow 的 ISEMPTY 都是这么建模的。B 等于「每次存查询时把字段类型写死进条件」。C 等于「先修一半」。

席位意见:荐 A,回退 B。实测的生产路径是:objectui 把已存视图规则里的「为空」原样发给服务端,服务端翻译时不看类型。A 不需要改任何调用方;B 要先改 3 个服务端入口,还要推翻一条 5 天前的裁决。

您要做的:回一个字母 —— A / B / C。

Background

• Ruling B (5861435168), verbatim: 「@objectstack/spec declares what 「is empty」 means once, per field type: text-like = null or ''; multi-value (multi-select, tags, multi-value lookup) = null or []; every other type = null only. The three objectui builders read that one lowering; none keeps a meaning of its own.」 Execution item 1 places it as 「a per-type table in filter.zod.ts」 applied at the lowering.
• The dispatch measured, and this seat re-read on origin/main, that the lowered FilterCondition can carry the text arm and the null arm but not the multi-value arm.

Governing text

• The empty-list refusal, ruling 乙 on [finding] the comparand-SHAPE face declares it closes the door "for every driver at once", but an array in the IMPLICIT-EQUALITY slot passes it — and driver-mongodb alone answers it, as an exact-array match #19757 (record 5793368540), packages/spec/src/data/filter-comparand-shape.ts, verbatim: 「An EMPTY array is still an array: { tags: [] } is refused too.」 Re-check: git show origin/main:packages/spec/src/data/filter-comparand-shape.ts | grep -c "An EMPTY array is still an array" → 1; control grep -c "Refused BY RULING" on the same file → 15.
• The operator vocabulary has no emptiness or size test: FILTER_OPERATORS in packages/spec/src/data/filter.zod.ts ends its "Special" row with '$null', '$exists'. Re-check: git show origin/main:packages/spec/src/data/filter.zod.ts | grep -c "'\$null', '\$exists'," → 1; control grep -c "export const FILTER_OPERATORS" → 1.
• An emptied multi-value set is stored as [], never null (the [Decision] Multi-value lookup after set_null member removal: does the emptied array read back as [] or null? #9447 maintainer ruling), packages/objectql/src/validation/record-validator.ts. Re-check: grep -c "empty set is representable" on that file at origin/main → 1; control grep -c "function isEmptyForRequired" → 1.
• The production path reaches the server typeless: objectui packages/core/src/utils/filter-converter.ts viewFilterRuleToNode passes a stored view rule's is_empty through as a valueless operator. packages/metadata-protocol/src/protocol.ts then lowers it with parsedFilter = parseFilterAST(parsedFilter), although the same file reads field declarations through resolveQueryFields. Re-check (objectui origin/main 9f0c84a): grep -c "'is_empty'," → 1, control grep -c "function viewFilterRuleToNode" → 1. objectstack origin/main 2f122b6e: grep -c "parsedFilter = parseFilterAST(parsedFilter)" → 1, control grep -c "resolveQueryFields" → 10.

Protocol statement. Option A adds one member to FILTER_OPERATORS and FieldOperatorsSchema (a widening, Clause-②: yes, minor). Option B changes ruling 乙's accept set for one shape (a widening at the shared face). C changes neither now. Every option changes the protocol; none is a code-only fix.

Options, with the costs the dev measured (report 5864899591, re-read by this seat where marked)

• A — a declared emptiness operator. Add $empty: boolean. Its describe IS the ruled table: text-like = STRING_VALUE_TYPES (null or ''); multi-value = isMultiValueField(def) (null or []); every other type = null. is_empty / is_not_empty lower typelessly to { f: { $empty: true|false } }, and each compile surface expands it by the field's declared type through one spec function.
  • Cost: all 8 compile surfaces implement one arm, in a staged landing: surfaces answer $empty first, and the lowering flips last. The two faces with no declarations (the formula matcher, objectql having) judge by value; they diverge only on a non-text column holding '', the write-door class record write door: '' skips every type check, so a number, boolean, date, datetime or time column stores an empty string — normalise it to null at the door (seam from objectui#10813) #20308 closed.
  • Gain: no lowering door needs a field type, [finding] the comparand-SHAPE face declares it closes the door "for every driver at once", but an array in the IMPLICIT-EQUALITY slot passes it — and driver-mongodb alone answers it, as an exact-array match #19757 stands untouched, and a stored filter keeps its meaning if its field's type changes.
• B — the type at lowering time. parseFilterAST takes a field-definition resolver and emits per-type fragments.
  • Cost: the multi-value fragment needs [] as an equality comparand, so ruling 乙 on [finding] the comparand-SHAPE face declares it closes the door "for every driver at once", but an array in the IMPLICIT-EQUALITY slot passes it — and driver-mongodb alone answers it, as an exact-array match #19757 (and its save-door twin) must be reopened for the empty list, and the SQL family, driver-memory and the formula matcher must learn to execute it on a JSON column.
  • The three runtime lowering doors (protocol.ts, engine.ts, service-analytics filter-normalizer.ts) must pass resolvers. The transport-schema door in data-engine.zod.ts has no object schema at all.
  • Lowered sharing-rule criteria freeze the field's type at authoring time.
• C — B's text and null arms now, the multi-value arm to its own ruling. Ruling B ships two of three arms; if the third later lands as A, the B half is rework.

Recommendation

A, fallback B. C is not recommended (a half-delivery).

os-decision-facets

• ① 项目长远合理性:A 让「为空」成为查询语言里的一个一等谓词,按字段声明的类型在执行处解释,和平台对文本操作符的既有做法(按声明类型判定)同一个模式,不产生特例。B 把类型相关的片段烘进每一条存储的条件,还要为一个 5 天前的裁决开口子,特例增生。两年后的主流形状:Notion 数据库查询的 is_empty 按属性类型定义,ServiceNow 有 ISEMPTY 操作符,都是「一个操作符、按类型解释」(⚠️ 本席未重新实测这两家)。
• ② 实际业务拉动:今天撞上的是已存视图的「为空」筛选。objectui 把它原样发给服务端,服务端不看类型;多值字段上 objectui 的构建器写出 $in: [''],SQL 驱动直接拒绝。A 不改任何调用方就修好它;B 要先改 3 个服务端入口。
• ③ 防 AI 犯错:A 给「为空」一个唯一的规范写法,AI 直接写 FilterCondition 时写 { f: { $empty: true } } 即可。B 下 AI 得手搓按类型的 $or,这正是 '' 被比到数字列上的来路(driver-sql on PostgreSQL answers 500 for a non-numeric string against a number field — where { amount: { $gt: "abc" } } is DATABASE_ERROR / 500 over REST, while InMemoryDriver and SQLite answer 200 with no rows #20336)。两者都是响亮拒绝:A 下未实现的执行面拒绝未知操作符,不会静默。
• ④ 创业阶段不扩散:A 新增一个操作符,但它是已声明的视图操作符 is_empty 的规范形态,不是新能力。B 不加操作符,却要推翻一条裁决并改更多入口。C 最省,但把裁决 B 留成半成品。

Prior rulings read: is_empty,empty,multi-value,equality → 17 hits; ADR-0037 Decision §1, ADR-0045 Decision §4, ADR-0045 Decision §7, ADR-0053 Decision §3, ADR-0055 Decision §2, ADR-0057 D12, ADR-0058 D3, ADR-0074 Decision §1, ADR-0076 D10 (each hit is the bare word in an unrelated decision; none rules on an emptiness predicate); thread: #20311 ruling 5861435168, #19757 ruling 乙 5793368540.

推荐:A(回退 B)。只看①选 A;②③④ 是否翻转:否。
置信缺口:Notion / ServiceNow 的建模未重新实测;生产环境里用了「为空」的已存视图与共享规则读不到;A 在 8 个执行面上的实现成本是 dev 的估计,未逐面实测。

After the ruling

• A: [Decision] what 「is empty」 means on a text column and on a multi-value column: null only (the spec's lowering today), or null OR '' / [] — three objectui builders disagree, and a stored sharing rule's rows depend on the answer #20311 (this seat) declares $empty in the spec: the operator, its describe carrying the ruled table, and one expansion function keyed on the field definition (type plus multiple). One sibling card per compile-surface lane (domain:engine: driver-sql and its heirs, turso RemoteTransport, driver-memory, driver-mongodb, formula, objectql having; domain:services: service-analytics' two faces) is Blocked-by: [Decision] what 「is empty」 means on a text column and on a multi-value column: null only (the spec's lowering today), or null OR '' / [] — three objectui builders disagree, and a stored sharing rule's rows depend on the answer #20311's spec PR. A last card flips the is_empty lowering to $empty once every surface answers. objectui#10813 converges its builders on $empty. Clause-②: yes, minor.
• B: a ruling amending [finding] the comparand-SHAPE face declares it closes the door "for every driver at once", but an array in the IMPLICIT-EQUALITY slot passes it — and driver-mongodb alone answers it, as an exact-array match #19757 乙 for the empty list; then [Decision] what 「is empty」 means on a text column and on a multi-value column: null only (the spec's lowering today), or null OR '' / [] — three objectui builders disagree, and a stored sharing rule's rows depend on the answer #20311 adds the resolver to parseFilterAST, and sibling cards convert the three lowering doors and teach the SQL family, driver-memory and the formula matcher empty-list equality on JSON columns.
• C: [Decision] what 「is empty」 means on a text column and on a multi-value column: null only (the spec's lowering today), or null OR '' / [] — three objectui builders disagree, and a stored sharing rule's rows depend on the answer #20311 ships the text and null arms with Part of; the multi-value arm returns to the box.

Dedupe

• MCP semantic search in this repository, filter operator for empty multi-value field empty array is_empty $empty operator: 0 hits.
• A local scan of the 1,197 most recently updated issues and PRs (open and closed) for $empty, $size, an empty list/array/set near filter/is_empty/operator, or is_empty near multi/[]: 3 hits, objectql: a per-aggregation filter refuses an unknown operator only when rows exist — aggregations: [{ filter: { amount: { $median: 1 } } }] answers 400 on a populated table and 200 on an empty one #20122, fix(objectql)!: having takes the rest of where's filter doors — the comparand-type door, row-independent refusals, a resolved { $field }, and a refused non-condition #20117 and fix(service-analytics)!: the analytics where door refuses a list in the equality slot instead of reading it as IN (#19888) #20008. They are an unknown-operator refusal on per-aggregation filters, having doors, and the analytics list-in-equality refusal. None is a carrier.

Dedupe words: is_empty multi-value empty list · $empty filter operator · empty array equality refused is_empty

[objectstack-fleet]

Ruling: batch #234 item 1 · letter A · maintainer 「同意」 2026-09-28T07:47Z

Director seat (objectstack#12708, summon #30 续 2, session_01AsCNgFBs8HCjwhyHQsFbx3). Provenance: maintainer, live PM chat with the director seat, 2026-09-28, replying 「同意」 to batch #234 as presented — this card item 1, recommendation A, fallback B, the full four-axis body in chat.

Ruled: A. The filter vocabulary gains a declared emptiness operator, $empty: boolean, whose describe IS the per-type table ruling B on #20311 (5861435168) set: text-like = null or ''; multi-value (multi-select, tags, multi-value lookup) = null or []; every other type = null only. is_empty / is_not_empty lower typelessly to { field: { $empty: true | false } }, and each compile surface expands it by the field's declared type through one spec function. B (the field type at lowering, reopening ruling 乙 on #19757 for the empty list) and C (ship the text and null arms now, the multi-value arm later) are not taken.

Readings that decided it:

• Long-term: "is empty" becomes a first-class predicate interpreted where the query executes, by declared type — the same pattern the text operators already follow; B bakes per-type fragments into every stored condition, freezes a field's type into stored sharing-rule criteria, and reopens a ruling five days old. Mainstream (from memory): Notion's is_empty is one operator interpreted per property type; ServiceNow has ISEMPTY; Airtable BLANK() — none writes type fragments into a stored condition.
• Real use: the live error is a stored view's 「is empty」 on a multi-value field (objectui's builder emits $in: [''], the SQL driver refuses it); A fixes it with no caller change; B must change three server lowering doors first.
• AI-safety: one canonical spelling; under B an AI hand-rolls per-type $or, the route by which '' reached number columns (driver-sql on PostgreSQL answers 500 for a non-numeric string against a number field — where { amount: { $gt: "abc" } } is DATABASE_ERROR / 500 over REST, while InMemoryDriver and SQLite answer 200 with no rows #20336). An execution surface that has not implemented $empty refuses an unknown operator loudly; nothing passes silently.
• Startup scope: one operator, and it is the canonical form of the already-declared view operator is_empty, not a new capability; FILTER_OPERATORS today ends its Special row at $null, $exists (filter.zod.ts:3032) and is_empty lowers to $null (:2460), so no surface carries a competing spelling to retire.

Execution parameters (ruled in the same stroke):

• [Decision] what 「is empty」 means on a text column and on a multi-value column: null only (the spec's lowering today), or null OR '' / [] — three objectui builders disagree, and a stored sharing rule's rows depend on the answer #20311 (spec, unblocked by this ruling): declare $empty in FILTER_OPERATORS and FieldOperatorsSchema, its describe carrying the ruled table; one expansion function keyed on the field definition (type plus multiple) that every compile surface calls; the is_empty / is_not_empty lowering keeps emitting $null until the flip card below. Clause-②: yes (widening), minor. Ruling 乙 on [finding] the comparand-SHAPE face declares it closes the door "for every driver at once", but an array in the IMPLICIT-EQUALITY slot passes it — and driver-mongodb alone answers it, as an exact-array match #19757 stays untouched: an empty list is still refused as an equality comparand.
• One sibling card per compile-surface lane, each Blocked-by: [Decision] what 「is empty」 means on a text column and on a multi-value column: null only (the spec's lowering today), or null OR '' / [] — three objectui builders disagree, and a stored sharing rule's rows depend on the answer #20311's spec PR: domain:engine — driver-sql and its heirs, turso RemoteTransport, driver-memory, driver-mongodb, formula, objectql having; domain:services — service-analytics' two faces. The two faces with no field declarations (the formula matcher, objectql having) judge by value, diverging only on a non-text column holding '' (the write-door class record write door: '' skips every type check, so a number, boolean, date, datetime or time column stores an empty string — normalise it to null at the door (seam from objectui#10813) #20308 closed).
• A last card flips the lowering to $empty once every surface answers it, with a pin that a stored view rule's 「is empty」 on a multi-value field returns the rows holding [] or null and refuses nothing.
• objectui#10813 converges the three builders on $empty after the spec release.
• Pins on [Decision] what 「is empty」 means on a text column and on a multi-value column: null only (the spec's lowering today), or null OR '' / [] — three objectui builders disagree, and a stored sharing rule's rows depend on the answer #20311: the describe string equals the ruled table; { tags: { $empty: true } } parses and { tags: [] } is still refused; the expansion function returns the text, multi-value and null arms for the three field kinds.

State: needs-user-decision removed here; no pm:* on this card — it is the ruling carrier, the work rides #20311. #20311: pm:blocked → pm:queue, its Blocked-by: #20399 resolved by this comment (note there in the same stroke). The Ruled line goes on this body.

[objectstack-fleet]

Pointer from domain:spec seat 1 (session_01B3TqpoQbTAfG7G74GMDWNW) · 2026-09-28T10:32Z. ⛔ No state change here.

Ruling A's placement parameter is amended by the maintainer. The ruling, verbatim: 「照 $like 先例分阶段」. $empty is declared in FieldOperatorsSchema now and joins FILTER_OPERATORS only with the flip card, because driver-memory accepts whatever FILTER_OPERATORS names and ignores an operator it has no arm for (every row). Ruling A's substance is unchanged. The record, with the readings and the provenance, is on #20311 as 5868169573.

[objectstack-fleet]

Closed: the decision was ruled and its execution chain has landed. The card only lacked a state

Triage seat (objectstack-wide, seat post #6015) · session_01AavokzJ5DndAwitDXvKy4U · 2026-09-30T07:36Z. ⛔ Not a claim, ⛔ not a dispatch.

Why this card surfaced. It carries no pm-state label and no needs-user-decision, so a count of the maintainer's pending decisions missed it, and one would think it was still waiting. It is not waiting: it is done.

The ruling (read, not recalled).

• A, 5865693155, batch 🔗 Broken links detected in documentation #234 item 1: the declared $empty operator, expanded per field type at each compile surface.
• The maintainer then amended its placement, 「照 $like 先例分阶段」 (record 5868169573 on [Decision] what 「is empty」 means on a text column and on a multi-value column: null only (the spec's lowering today), or null OR '' / [] — three objectui builders disagree, and a stored sharing rule's rows depend on the answer #20311; pointer 5868183894 here).

The execution, each closed completed:

• [Decision] what 「is empty」 means on a text column and on a multi-value column: null only (the spec's lowering today), or null OR '' / [] — three objectui builders disagree, and a stored sharing rule's rows depend on the answer #20311 (the per-type meaning, ruling B) via PR feat(spec): declare the staged $empty filter operator and its per-type expansion (#20311) #20442 (b810ddb6f): $empty declared and staged;
• filter: the engine's compile surfaces answer $empty by the field's declared type (driver-sql and heirs, turso remote, driver-memory, driver-mongodb, formula, objectql having) — ruling A on #20399 #20444, the engine faces (drivers, formula, objectql), via fb386074f5;
• analytics: service-analytics' two filter faces answer $empty by the field's declared type (read-scope SQL, the analytics where) — ruling A on #20399 #20445, the analytics faces, via 2b53993aca;
• filter: flip is_empty / is_not_empty to $empty and add it to FILTER_OPERATORS, once every compile surface answers it (the last step of ruling A on #20399) #20446, the flip, via PR feat(spec)!: $empty joins FILTER_OPERATORS, and is_empty / is_not_empty lower to it (#20446) #20570 (f1e921ab8e): $empty joins FILTER_OPERATORS, and is_empty / is_not_empty lower to it.

Nothing is left for the decision box. The release carries the flip as a BREAKING minor in the Version Packages PR #20639 (17.6.0).