fix(pages): deferred props, action responses and dev rescan errors

packages/react/src/plugin-pages.ts

@@ -151,7 +151,16 @@ export function pagesPlugin(pagesDir: string, options?: PagesPluginOptions): Plu
         if (event === 'change' && !normalizedPath.endsWith('.md')) {
           return;
         }
-        await runRescan();
+        try {
+          await runRescan();
+        } catch (error) {
+          // Keep the last good scan; the next change rescans.
+          server.config.logger.error(error instanceof Error ? error.message : String(error), {
+            error: error instanceof Error ? error : undefined,
+            timestamp: true,
+          });
+          return;
+        }
         invalidatePageModules(server);
       };
 

packages/react/test/unit/plugin-pages.test.ts

@@ -1,6 +1,6 @@
 import { mkdirSync, rmSync, writeFileSync } from 'node:fs';
 import { join } from 'node:path';
-import { afterEach, describe, expect, it } from 'vite-plus/test';
+import { afterEach, describe, expect, it, vi } from 'vite-plus/test';
 import { pagesPlugin } from '../../src/plugin-pages.ts';
 
 const TMP = join(import.meta.dirname, '__tmp_pages_plugin__');
@@ -45,7 +45,7 @@ function writePage(relativePath: string, source: string): void {
   writeFileSync(full, source);
 }
 
-function setupWatcher(plugin: PagesPluginHooks) {
+function setupWatcher(plugin: PagesPluginHooks, logError = vi.fn(), invalidateModule = vi.fn()) {
   const handlers = new Map<string, Array<(path: string) => Promise<void> | void>>();
   plugin.configureServer?.({
     watcher: {
@@ -55,7 +55,10 @@ function setupWatcher(plugin: PagesPluginHooks) {
         handlers.set(event, eventHandlers);
       },
     },
-    environments: {},
+    environments: {
+      client: { moduleGraph: { getModuleById: (id: string) => ({ id }), invalidateModule } },
+    },
+    config: { logger: { error: logError } },
   });
   return handlers;
 }
@@ -104,4 +107,41 @@ describe('pagesPlugin dev config', () => {
 
     expect(renderer).toContain('"test": () => import');
   });
+
+  it('logs a page scan error from the watcher and keeps the last scan', async () => {
+    writePage('index.tsx', 'export default function Index() { return <h1>Home</h1>; }\n');
+
+    const plugin = pagesPlugin(PAGES_DIR) as PagesPluginHooks;
+    getHookHandler(plugin.config)({}, { command: 'serve' });
+    await getHookHandler(plugin.buildStart).call({});
+    const logError = vi.fn();
+    const invalidateModule = vi.fn();
+    const handlers = setupWatcher(plugin, logError, invalidateModule);
+    const emitAdd = async (relativePath: string) => {
+      for (const handler of handlers.get('add') ?? []) {
+        await expect(handler(join(PAGES_DIR, relativePath))).resolves.toBeUndefined();
+      }
+    };
+
+    writePage('about.md', '---\nlayout: docs\n---\n# About\n');
+    await emitAdd('about.md');
+
+    expect(logError).toHaveBeenCalledTimes(1);
+    expect(logError.mock.calls[0]?.[0]).toContain("specifies layout 'docs'");
+    expect(invalidateModule).not.toHaveBeenCalled();
+    const renderer = await getHookHandler(plugin.load)('\0virtual:void-pages-renderer');
+    expect(renderer).toContain('"index": () => import');
+    expect(renderer).not.toContain('"about"');
+
+    writePage(
+      '_layouts/docs.tsx',
+      'export default function Docs({ children }) { return <main>{children}</main>; }\n',
+    );
+    await emitAdd('_layouts/docs.tsx');
+
+    expect(logError).toHaveBeenCalledTimes(1);
+    expect(invalidateModule).toHaveBeenCalled();
+    const recovered = await getHookHandler(plugin.load)('\0virtual:void-pages-renderer');
+    expect(recovered).toContain('"about"');
+  });
 });

packages/solid/src/plugin-pages.ts

@@ -128,7 +128,16 @@ export function pagesPlugin(pagesDir: string, options?: PagesPluginOptions): Plu
         if (event === 'change' && !normalizedPath.endsWith('.md')) {
           return;
         }
-        await runRescan();
+        try {
+          await runRescan();
+        } catch (error) {
+          // Keep the last good scan; the next change rescans.
+          server.config.logger.error(error instanceof Error ? error.message : String(error), {
+            error: error instanceof Error ? error : undefined,
+            timestamp: true,
+          });
+          return;
+        }
         invalidatePageModules(server);
       };
 

packages/solid/test/unit/plugin-pages.test.ts

@@ -1,6 +1,6 @@
 import { mkdirSync, rmSync, writeFileSync } from 'node:fs';
 import { join } from 'node:path';
-import { afterEach, describe, expect, it } from 'vite-plus/test';
+import { afterEach, describe, expect, it, vi } from 'vite-plus/test';
 import { pagesPlugin } from '../../src/plugin-pages.ts';
 
 const TMP = join(import.meta.dirname, '__tmp_pages_plugin__');
@@ -36,7 +36,7 @@ function writePage(relativePath: string, source: string): void {
   writeFileSync(full, source);
 }
 
-function setupWatcher(plugin: PagesPluginHooks) {
+function setupWatcher(plugin: PagesPluginHooks, logError = vi.fn(), invalidateModule = vi.fn()) {
   const handlers = new Map<string, Array<(path: string) => Promise<void> | void>>();
   plugin.configureServer?.({
     watcher: {
@@ -46,7 +46,10 @@ function setupWatcher(plugin: PagesPluginHooks) {
         handlers.set(event, eventHandlers);
       },
     },
-    environments: {},
+    environments: {
+      client: { moduleGraph: { getModuleById: (id: string) => ({ id }), invalidateModule } },
+    },
+    config: { logger: { error: logError } },
   });
   return handlers;
 }
@@ -74,4 +77,41 @@ describe('pagesPlugin dev HMR', () => {
 
     expect(renderer).toContain('"test": () => import');
   });
+
+  it('logs a page scan error from the watcher and keeps the last scan', async () => {
+    writePage('index.tsx', 'export default function Index() { return <h1>Home</h1>; }\n');
+
+    const plugin = pagesPlugin(PAGES_DIR) as PagesPluginHooks;
+    getHookHandler(plugin.config)({}, { command: 'serve' });
+    await getHookHandler(plugin.buildStart).call({});
+    const logError = vi.fn();
+    const invalidateModule = vi.fn();
+    const handlers = setupWatcher(plugin, logError, invalidateModule);
+    const emitAdd = async (relativePath: string) => {
+      for (const handler of handlers.get('add') ?? []) {
+        await expect(handler(join(PAGES_DIR, relativePath))).resolves.toBeUndefined();
+      }
+    };
+
+    writePage('about.md', '---\nlayout: docs\n---\n# About\n');
+    await emitAdd('about.md');
+
+    expect(logError).toHaveBeenCalledTimes(1);
+    expect(logError.mock.calls[0]?.[0]).toContain("specifies layout 'docs'");
+    expect(invalidateModule).not.toHaveBeenCalled();
+    const renderer = await getHookHandler(plugin.load)('\0virtual:void-pages-renderer');
+    expect(renderer).toContain('"index": () => import');
+    expect(renderer).not.toContain('"about"');
+
+    writePage(
+      '_layouts/docs.tsx',
+      'export default function Docs(props) { return <main>{props.children}</main>; }\n',
+    );
+    await emitAdd('_layouts/docs.tsx');
+
+    expect(logError).toHaveBeenCalledTimes(1);
+    expect(invalidateModule).toHaveBeenCalled();
+    const recovered = await getHookHandler(plugin.load)('\0virtual:void-pages-renderer');
+    expect(recovered).toContain('"about"');
+  });
 });

packages/svelte/src/plugin-pages.ts

@@ -135,7 +135,16 @@ export function pagesPlugin(pagesDir: string, options?: PagesPluginOptions): Plu
         if (event === 'change' && !normalizedPath.endsWith('.md')) {
           return;
         }
-        await runRescan();
+        try {
+          await runRescan();
+        } catch (error) {
+          // Keep the last good scan; the next change rescans.
+          server.config.logger.error(error instanceof Error ? error.message : String(error), {
+            error: error instanceof Error ? error : undefined,
+            timestamp: true,
+          });
+          return;
+        }
         invalidatePageModules(server);
       };
 

packages/svelte/test/unit/plugin-pages.test.ts

@@ -1,6 +1,6 @@
 import { mkdirSync, rmSync, writeFileSync } from 'node:fs';
 import { join } from 'node:path';
-import { afterEach, describe, expect, it } from 'vite-plus/test';
+import { afterEach, describe, expect, it, vi } from 'vite-plus/test';
 import { pagesPlugin } from '../../src/plugin-pages.ts';
 
 const TMP = join(import.meta.dirname, '__tmp_pages_plugin__');
@@ -36,7 +36,7 @@ function writePage(relativePath: string, source: string): void {
   writeFileSync(full, source);
 }
 
-function setupWatcher(plugin: PagesPluginHooks) {
+function setupWatcher(plugin: PagesPluginHooks, logError = vi.fn(), invalidateModule = vi.fn()) {
   const handlers = new Map<string, Array<(path: string) => Promise<void> | void>>();
   plugin.configureServer?.({
     watcher: {
@@ -46,7 +46,10 @@ function setupWatcher(plugin: PagesPluginHooks) {
         handlers.set(event, eventHandlers);
       },
     },
-    environments: {},
+    environments: {
+      client: { moduleGraph: { getModuleById: (id: string) => ({ id }), invalidateModule } },
+    },
+    config: { logger: { error: logError } },
   });
   return handlers;
 }
@@ -75,6 +78,43 @@ describe('pagesPlugin dev HMR', () => {
     expect(renderer).toContain('"test": () => import');
   });
 
+  it('logs a page scan error from the watcher and keeps the last scan', async () => {
+    writePage('index.svelte', '<h1>Home</h1>\n');
+
+    const plugin = pagesPlugin(PAGES_DIR) as PagesPluginHooks;
+    getHookHandler(plugin.config)({}, { command: 'serve' });
+    await getHookHandler(plugin.buildStart).call({});
+    const logError = vi.fn();
+    const invalidateModule = vi.fn();
+    const handlers = setupWatcher(plugin, logError, invalidateModule);
+    const emitAdd = async (relativePath: string) => {
+      for (const handler of handlers.get('add') ?? []) {
+        await expect(handler(join(PAGES_DIR, relativePath))).resolves.toBeUndefined();
+      }
+    };
+
+    writePage('about.md', '---\nlayout: docs\n---\n# About\n');
+    await emitAdd('about.md');
+
+    expect(logError).toHaveBeenCalledTimes(1);
+    expect(logError.mock.calls[0]?.[0]).toContain("specifies layout 'docs'");
+    expect(invalidateModule).not.toHaveBeenCalled();
+    const renderer = await getHookHandler(plugin.load)('\0virtual:void-pages-renderer');
+    expect(renderer).toContain('"index": () => import');
+    expect(renderer).not.toContain('"about"');
+
+    writePage(
+      '_layouts/docs.svelte',
+      '<script>let { children } = $props();</script>\n<main>{@render children()}</main>\n',
+    );
+    await emitAdd('_layouts/docs.svelte');
+
+    expect(logError).toHaveBeenCalledTimes(1);
+    expect(invalidateModule).toHaveBeenCalled();
+    const recovered = await getHookHandler(plugin.load)('\0virtual:void-pages-renderer');
+    expect(recovered).toContain('"about"');
+  });
+
   it('excludes @void/svelte from the void worker optimizer in dev', () => {
     writePage('index.svelte', '<h1>Home</h1>\n');
 

packages/void/src/pages/islands-plugin.ts

@@ -327,16 +327,25 @@ export function watchPagesForRescan(
     }
     debounceTimer = setTimeout(() => {
       debounceTimer = null;
-      pending = scanPages(root, { pagesDir }).then((pageScan) => {
-        onRescan(pageScan);
-        for (const env of Object.values(server.environments)) {
-          const mod = env.moduleGraph.getModuleById('\0' + ISLANDS_RENDERER_ID);
-          if (mod) {
-            env.moduleGraph.invalidateModule(mod);
-          }
-        }
-        pending = null;
-      });
+      pending = scanPages(root, { pagesDir })
+        .then(
+          (pageScan) => {
+            onRescan(pageScan);
+            for (const env of Object.values(server.environments)) {
+              const mod = env.moduleGraph.getModuleById('\0' + ISLANDS_RENDERER_ID);
+              if (mod) {
+                env.moduleGraph.invalidateModule(mod);
+              }
+            }
+          },
+          () => {
+            // The adapter pages plugin runs the same scan on the same events and
+            // logs its error. Keep the last good scan until the next change.
+          },
+        )
+        .finally(() => {
+          pending = null;
+        });
     }, 50);
   };
 

packages/void/src/pages/navigation-engine.ts

@@ -293,8 +293,14 @@ export async function createPageNavigationEngine(
       }
 
       for (const [key, group] of Object.entries(pageData.deferredKeys) as Array<[string, string]>) {
-        const ref = adapter.createDeferred();
-        const value = resolved ? adapter.resolveDeferred(ref, pageData.props[key]) : ref;
+        let value = adapter.createDeferred();
+        if (resolved) {
+          const error = pageData.deferredErrors?.[group];
+          value =
+            error === undefined
+              ? adapter.resolveDeferred(value, pageData.props[key])
+              : adapter.rejectDeferred(value, error);
+        }
         this.keyRefs[key] = value;
         this.props[key] = value;
         (this.groups[group] ??= []).push(key);
@@ -340,20 +346,7 @@ export async function createPageNavigationEngine(
       }
 
       if (data !== undefined) {
-        if (typeof data === 'object' && data !== null && !Array.isArray(data)) {
-          let resolvedAny = false;
-          for (const [key, value] of Object.entries(data as Record<string, unknown>)) {
-            if (this.keyRefs[key]) {
-              this.resolveKey(key, value);
-              resolvedAny = true;
-            }
-          }
-          if (!resolvedAny) {
-            this.resolveGroup(group, data);
-          }
-        } else {
-          this.resolveGroup(group, data);
-        }
+        this.resolveGroup(group, data);
       } else if (error !== undefined) {
         this.rejectGroup(group, typeof error === 'string' ? error : String(error));
       }
@@ -388,7 +381,6 @@ export async function createPageNavigationEngine(
 
     private retainOnly(keys: Set<string>, props: Record<string, unknown>): void {
       const keyRefs: Record<string, unknown> = {};
-      const groups: Record<string, Array<string>> = {};
       for (const [key, ref] of Object.entries(this.keyRefs)) {
         if (keys.has(key)) {
           keyRefs[key] = ref;
@@ -397,22 +389,24 @@ export async function createPageNavigationEngine(
           adapter.rejectDeferred(ref, 'Navigation disposed before deferred props resolved');
         }
       }
-      for (const [group, groupKeys] of Object.entries(this.groups)) {
-        const preservedGroupKeys = groupKeys.filter((key) => keys.has(key));
-        if (preservedGroupKeys.length > 0) {
-          groups[group] = preservedGroupKeys;
-        }
-      }
+      // Groups keep every key so a group resolves with its original shape.
+      // Keys dropped from keyRefs are skipped when the group settles.
       this.props = props;
       this.keyRefs = keyRefs;
-      this.groups = groups;
       adapter.onDeferredUpdate?.(this.props);
     }
 
+    /** A one-key group takes the raw value; a larger group takes each key from the object. */
     private resolveGroup(group: string, data: unknown): void {
       const keys = this.groups[group] ?? (this.keyRefs[group] ? [group] : []);
+      if (keys.length === 1) {
+        this.resolveKey(keys[0]!, data);
+        return;
+      }
+      const values =
+        typeof data === 'object' && data !== null ? (data as Record<string, unknown>) : {};
       for (const key of keys) {
-        this.resolveKey(key, data);
+        this.resolveKey(key, values[key]);
       }
     }