spec(leaf): mount(el,props) escape hatch — cross-Vue-major leaf render (fixes #44 systemically)

[rubenvdlinde]

What

OpenSpec change proposal (spec only — no implementation) for a mount(el, props) / unmount(el) render escape hatch on the cross-app leaf registry, so a sibling app's render-surface leaf renders on an OpenRegister host object page even when host and leaf are on different Vue majors. Resolves hermiq#44 systemically and unblocks the hermiq, decidesk, and openconnector leaves.

Problem (confirmed live — hermiq#44)

ADR-019 leaf rendering passes a sibling app's SFC to the host's dynamic-component renderer. It works only when host and leaf share a Vue major. Host (OpenBuild/OR via @conduction/nextcloud-vue v1) = Vue 2.7; hermiq/decidesk/openconnector leaves = Vue 3. A Vue-3-compiled SFC crashes under the Vue-2.7 renderer (blank body, undefined data reads). Only built-ins render, because the host swaps them to its own local SFC (LIB_INTEGRATION_COMPONENTS, openregister#1958). A bespoke cross-major component has no local twin, so it hits the raw cross-Vue trap.

Design

A render-surface leaf MAY supply mount(el, props) + unmount(el) (renderMode: 'mount') instead of the SFC tab/widget. The host renders a bare container element; the leaf instantiates its own framework (createApp(...).mount(el)) inside it and tears down on unmount. The DOM element is the neutral hand-off — each side runs its own Vue. Host consumers (CnObjectSidebar / CnDetailPage / CnDashboardPage) grow the mount lifecycle (mount on show, unmount on hide/teardown, re-mount on object change, error isolation). LeafDescriptor.renderMode carries the mode to discovery + parity. The SFC path stays the default for same-major/built-in leaves (backward compatible). Command boundary is unchanged (ADR-041); ADR-066 (render-and-read boundary) is amended with the mount clause.

Deliverable

openspec/changes/leaf-mount-render-escape-hatch/ — proposal.md, design.md (mount contract, host lifecycle, renderMode metadata, gate-24 parity implication, ADR-066 amendment text, leaf migration list), specs/leaf-mount-render/spec.md (6 normative requirements), tasks.md (split by repo). openspec validate --strict clean.

Proposal only — do NOT merge. For human review.

[github-actions]

Quality Report — ConductionNL/openregister @ cdaad0f

Check	PHP	Vue	Security	License	Tests
lint	✅
phpcs	✅
phpmd	✅
psalm	✅
phpstan	✅
phpmetrics	✅
eslint		✅
stylelint		✅
composer			✅	✅ 174/174
npm			✅	✅ 555/555
PHPUnit					❌
Newman					❌
Playwright					⏭️

---

Quality workflow — 2026-07-25 21:05 UTC

Download the full PDF report from the workflow artifacts.