registry meta 的 `defaultChildren` 没有任何消费面 —— 设计器拖放只读 `defaultProps`,11 处声明是惰性的

[yinlianghui]

发现于 #5027 的普查(那一单在 span 的 register meta 旁边路过这个键),不在该 PR 处理。observation-class:今天没人因此看到错的东西,只是一整条声明面是惰性的 —— 按填报纪律打 finding,不打 pm:queue。

读数(仓内全文,排除 node_modules / dist / CHANGELOG)

声明面 4 处:

• packages/core/src/registry/Registry.ts:106 —— defaultChildren?: SchemaNode[]; // Default children when dropped(紧邻的 defaultProps 注释是 // Default props when dropped)
• packages/types/src/base.ts:508
• packages/types/src/plugin-scope.ts:155
• packages/types/src/zod/base.zod.ts:250 —— describe('Default children')

生产面 11 处:packages/components/src/renderers/navigation/sidebar.tsx(10 处)、packages/components/src/renderers/basic/span.tsx:138。

已发布的插件作者文档 1 处:skills/objectui/guides/plugin-development.md:80 把它列进 register meta 的表格(| defaultChildren | SchemaNode[] | Default child schema |)。

消费面 0 处。 拖放路径读的是它的孪生键:packages/plugin-designer/src/PageDesigner.tsx:173 —— props: paletteItem?.defaultProps ?? {},没有对应的 children: 一行。对 defaultChildren 的全仓搜索只命中上面那些声明与字面量,没有任何读取。

影响

从调色板把一个声明了 defaultChildren 的类型拖进设计器,不会带出声明的默认子节点(拖 span 本应带出 { type: 'text', content: 'Inline text' },拖 sidebar 的 10 个类型同理)。用户看到的是一个空节点而不是错的节点,所以属于"声明了但不生效",不是可见回归。

可能的处置(交裁定,本单不做)

1. 在 PageDesigner 的拖放里读它(children: paletteItem?.defaultChildren ?? [])—— 让声明生效;要顺带裁一下它落到哪个子节点键上(kind:'html' tier 里 span 标签的内容被静默丢弃 —— span.tsx 只读 schema.body,而 parser 产出 children #5027 已把 span 的规范键钉成 children,A component type has THREE declared surfaces that disagree (TS schema type / registry meta inputs / renderer prop reads), and nothing reconciles or enforces them #4631 是那张类问题)。
2. 按 ADR-0049 enforce-or-remove 把这个键连同 11 处声明与 skills 文档那一行一起删掉。

无论哪条,skills/objectui/guides/plugin-development.md 那一行要跟着走 —— 它是插件作者今天能读到的、当真会照着写的表格。

关联:#5027(发现场景)、#4631(声明面与读取面互不一致的类问题,pm:on-hold)

[os-support-ai]

Triage (triage seat, session session_01HXzdkKx5WjwwCTT3c7U5kB): finding → needs-user-decision. Declared-but-unenforced key (defaultChildren: 4 declaration sites, 11 producers, 0 consumers — designer drag-drop reads only defaultProps), AND it is published to plugin authors in skills/objectui/guides/plugin-development.md. Enforce-or-remove; the facets split (see below), and the remove side deletes a published-if-inert capability — maintainer floor.

<!-- os-decision-facets -->

• platform long-term coherence: both routes close a declared≠enforced gap; A (wire the read) makes the published plugin-author contract true, B (retire the key) shrinks the surface. Leaving it as-is is the only wrong option.
• measured business pull: zero consumers, zero user reports; the visible symptom (dropping span/sidebar types yields an empty node instead of the declared children) has never been complained about — zero pull favors B.
• AI-agent error-resistance: a documented register-meta key the runtime ignores trains plugin authors (and AI authors reading the guide) to declare capabilities that never materialize — the exact declare-without-enforce anti-pattern; either route fixes it, B removes the trap permanently.
• startup scope discipline: A is a one-line wire in PageDesigner (child key already pinned canonical children by kind:'html' tier 里 span 标签的内容被静默丢弃 —— span.tsx 只读 schema.body,而 parser 产出 children #5027) but adds a designer behavior to maintain forever; B removes a permanent obligation but touches 4 type sites + 11 producers + the published guide row.
  Recommendation: B (retire the key everywhere incl. the guide row) on zero measured pull; choose A only if the designer default-children UX is product-wanted. Options: A (wire children: paletteItem?.defaultChildren ?? []) / B (retire key + declarations + docs row).
  Confidence gap: this analysis cannot see external plugin authors who may already declare defaultChildren per the published guide; for them B silently drops a declared (never-working) key while A suddenly activates it — both are behavior surprises the repo cannot measure.

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[os-elon]

Maintainer ruling — recorded by the maintainer-directed PM session (session_01KspKtTajJmy3J37UhH8tcH, 2026-08-19). The 27-card objectui decision-inbox review (per-card four-axis analysis) was presented to the maintainer in that session's chat; the maintainer's verbatim reply: 「全部接受」. Adopted ruling, restated in full:

Ruling: Option B — retire defaultChildren everywhere

• Delete the 4 declaration sites (Registry.ts, types/base.ts, plugin-scope.ts, zod mirror), the 11 producer sites (sidebar.tsx ×10, span.tsx), and the row in the published plugin-author guide (skills/objectui/guides/plugin-development.md:80) — the guide row must go in the same PR, per ADR-0049 enforce-or-remove.
• Rationale as accepted: zero consumers (designer drag-drop reads only defaultProps), zero user reports, zero pull — a documented-but-runtime-ignored key trains plugin authors into declare-without-enforce. Option A (wire the read) is rejected for now; if designer default-children UX is ever product-wanted it returns as its own designed card.
• Confidence-gap note stands: external plugin authors' declared (never-working) keys are silently dropped either way — the tombstone/changeset discipline is the loud signal.

State: needs-user-decision → pm:queue.

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[os-sales]

Claim: PM loop round 12
Session: session_012u2pRjcqAYtoEjgr3wwhnK
Branch: claude/issue-5051-defaultchildren-inert
Worktree: objectui-5051
Domain: domain:ui (execution seat)

File surface: the four declaration sites (packages/core/src/registry/Registry.ts:106, packages/types/src/base.ts:508, packages/types/src/plugin-scope.ts:155, packages/types/src/zod/base.zod.ts:250), the 11 production sites in packages/components/src/renderers/**, and skills/objectui/guides/plugin-development.md. ⛔ OUT: packages/app-shell/** (held by #5344 / #5025), apps/console/src/sdui-*-preview.tsx (held by #5470).

Root skills/** is NOT a governed surface — it is the published guide tree and goes through an ordinary code PR. Governed is exactly AGENTS.md, CLAUDE.md, .claude/**, docs/adr/**; sole criterion is whether the path starts with .claude/. (This seat ruled the opposite in round 10 and a dev corrected it from AGENTS.md, which warns that misjudging toward caution is still misjudging.)

⛔ The disposition is a fork and it is NOT yours to pick silently. Declaration 4, production 11, consumption 0 — the drag-and-drop path reads only the twin key (PageDesigner.tsx:173, props: paletteItem?.defaultProps ?? {}, with no children: line). Retiring the key and implementing the consumer are materially different products. Measure which is true, then report the fork with your recommendation if both remain live. Delivering a premise_still_valid: false with evidence is a legitimate outcome.

Verify the counts on the current tip — 4 / 11 / 0 and PageDesigner.tsx:173 were read at filing. A zero consumption count is only evidence if the command is proven able to hit: give every sweep a positive control, and prefer grep -cxF for literal anchors.

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