feat(studio): seed a new record page from the object's default detail page (#1541)

.changeset/b1-seed-record-page.md

@@ -0,0 +1,7 @@
+---
+"@object-ui/app-shell": minor
+---
+
+Studio: new record pages seed their layout from the object's default detail page.
+
+Creating a `pageType: 'record'` page bound to an object previously started from a blank canvas. The `page` resource now has a `createSeed` hook that, on create, fetches the bound object and seeds the page's `regions` from `buildDefaultPageSchema(objectDef)` — the same auto-generated detail layout the runtime renders by default. Authors start by tweaking the default page, not rebuilding it. A generic async `createSeed` hook was added to `MetadataResourceConfig` (merged into the create body after `createBuildBody`/`createDefaults`; best-effort). Completes #1541's Studio authoring path.

packages/app-shell/src/views/metadata-admin/ResourceEditPage.tsx

@@ -796,14 +796,27 @@ function MetadataResourceEditPageImpl({
       // or `{ list: { data: { object } } }` for view) is present so
       // the saved body satisfies its JSONSchema. User-supplied values
       // always win over the defaults.
-      const builtBody = createMode
+      let builtBody = createMode
         ? (config.createBuildBody
             ? config.createBuildBody(draft)
             : { ...(config.createDefaults ?? {}), ...draft })
         // Edit mode: serialise the editor draft back to the wire shape
         // (inverse of `toDraft` — e.g. `view` folds the `{ list | form }`
         // family key back into the ViewItem `config` wrapper).
         : (config.fromDraft ? config.fromDraft(draft) : draft);
+      // Async create-time augmentation (e.g. seed a record page's regions from
+      // the bound object's synthesized default). Best-effort — a failure leaves
+      // the un-augmented body. User/builder-supplied keys win over the seed.
+      if (createMode && config.createSeed) {
+        try {
+          const seeded = await config.createSeed(draft, { client });
+          if (seeded && typeof seeded === 'object') {
+            // Seed wins over the empty defaults (`builtBody` already folded the
+            // user's draft in, which only carries default-empty `regions`).
+            builtBody = { ...(builtBody as Record<string, unknown>), ...seeded };
+          }
+        } catch { /* seed is best-effort; proceed with the un-augmented body */ }
+      }
       const savedName = String(
         (builtBody as Record<string, unknown>)[identityField] ?? draft[identityField] ?? name,
       );

packages/app-shell/src/views/metadata-admin/anchors.page-seed.test.ts

@@ -0,0 +1,57 @@
+// Copyright (c) 2025 ObjectStack. Licensed under the Apache-2.0 license.
+
+import { describe, it, expect } from 'vitest';
+import { registerBuiltinAnchors } from './anchors';
+import { resolveResourceConfig } from './registry';
+
+/**
+ * #1541 — the `page` resource's `createSeed` hook seeds a record page's regions
+ * from the bound object's synthesized default detail page, so authoring starts
+ * from the auto-generated layout instead of a blank canvas.
+ */
+registerBuiltinAnchors();
+
+const objectDef = {
+  name: 'showcase_invoice',
+  label: 'Invoice',
+  fields: {
+    name: { type: 'text', label: 'Invoice Number' },
+    status: { type: 'select', label: 'Status', options: [{ value: 'draft', label: 'Draft' }, { value: 'paid', label: 'Paid' }] },
+    account: { type: 'lookup', label: 'Account', reference: 'showcase_account' },
+    total: { type: 'currency', label: 'Total' },
+  },
+};
+
+function clientReturning(def: any) {
+  return { get: async (_type: string, _name: string) => def };
+}
+
+describe('page createSeed (record-page region seeding)', () => {
+  const cfg = resolveResourceConfig('page');
+
+  it('is registered on the page resource', () => {
+    expect(typeof cfg.createSeed).toBe('function');
+  });
+
+  it('seeds regions from the bound object default for a record page', async () => {
+    const seeded = await cfg.createSeed!({ type: 'record', object: 'showcase_invoice' }, { client: clientReturning(objectDef) });
+    expect(Array.isArray((seeded as any).regions)).toBe(true);
+    expect((seeded as any).regions.length).toBeGreaterThan(0);
+  });
+
+  it('returns {} for a non-record page (no object binding to synth from)', async () => {
+    const seeded = await cfg.createSeed!({ type: 'app', object: 'showcase_invoice' }, { client: clientReturning(objectDef) });
+    expect(seeded).toEqual({});
+  });
+
+  it('returns {} when no object is chosen', async () => {
+    const seeded = await cfg.createSeed!({ type: 'record' }, { client: clientReturning(objectDef) });
+    expect(seeded).toEqual({});
+  });
+
+  it('is best-effort — swallows a client/synth failure and returns {}', async () => {
+    const failing = { get: async () => { throw new Error('boom'); } };
+    const seeded = await cfg.createSeed!({ type: 'record', object: 'showcase_invoice' }, { client: failing });
+    expect(seeded).toEqual({});
+  });
+});

packages/app-shell/src/views/metadata-admin/anchors.ts

@@ -156,6 +156,24 @@ export function registerBuiltinAnchors(): void {
       },
     },
     createDefaults: { type: 'record', kind: 'full', regions: [] },
+    // Seed a record page's regions from the bound object's synthesized default
+    // detail page, so authoring starts from the auto-generated layout (the same
+    // one the runtime renders by default) instead of a blank canvas.
+    createSeed: async (draft, { client }) => {
+      if (draft?.type !== 'record' || !draft?.object) return {};
+      try {
+        const objectDef = await client.get('object', String(draft.object));
+        if (!objectDef || typeof objectDef !== 'object') return {};
+        const { buildDefaultPageSchema } = await import('@object-ui/plugin-detail');
+        const synth = buildDefaultPageSchema(objectDef as any) as Record<string, any>;
+        const seed: Record<string, unknown> = {};
+        if (Array.isArray(synth?.regions) && synth.regions.length) seed.regions = synth.regions;
+        if (synth?.template) seed.template = synth.template;
+        return seed;
+      } catch {
+        return {};
+      }
+    },
   });
 
   // A view is the canonical first-class ViewItem ({ viewKind, config }),

packages/app-shell/src/views/metadata-admin/registry.ts

@@ -190,6 +190,20 @@ export interface MetadataResourceConfig {
    */
   createBuildBody?: (draft: Record<string, unknown>) => Record<string, unknown>;
 
+  /**
+   * Async create-time body augmentation that needs runtime context the pure
+   * {@link createBuildBody} can't reach — e.g. fetching another metadata item.
+   * Its returned fields are merged into the create body AFTER `createBuildBody`
+   * / `createDefaults`. Best-effort: errors are swallowed (the create still
+   * proceeds with the un-augmented body). Used by `page` to seed a record
+   * page's `regions` from the bound object's synthesized default detail page,
+   * so authoring starts from the auto-generated layout instead of blank.
+   */
+  createSeed?: (
+    draft: Record<string, unknown>,
+    ctx: { client: any },
+  ) => Record<string, unknown> | Promise<Record<string, unknown>>;
+
   /**
    * Optional load-time normaliser: the wire item returned by the server
    * (`layered.effective` / a pending draft) → the draft shape the editor