fix(desktop): guard print crash Closes #101880

apps/desktop/src/app/chat/right-rail/preview-pane.test.tsx

@@ -698,6 +698,31 @@ describe('PreviewPane console state', () => {
       profile: 'macmini'
     })
   })
+
+  // #101880: guest window.print() segfaults the macOS native print panel —
+  // the pane stubs print in every guest document so the panel is never built.
+  it('stubs window.print in the guest on dom-ready', async () => {
+    let rendered!: ReturnType<typeof render>
+    await act(async () => {
+      rendered = render(
+        <PreviewPane
+          target={{ kind: 'url', label: 'Preview', source: 'http://localhost:5174', url: 'http://localhost:5174' }}
+        />
+      )
+    })
+
+    const webview = rendered.container.querySelector('webview') as HTMLElement & Record<string, unknown>
+    const executeJavaScript = vi.fn(async (_code: string) => undefined)
+
+    Object.assign(webview, { executeJavaScript })
+
+    act(() => {
+      webview.dispatchEvent(new Event('dom-ready'))
+    })
+
+    expect(executeJavaScript).toHaveBeenCalledOnce()
+    expect(String(executeJavaScript.mock.calls[0]?.[0])).toContain('window.print')
+  })
 })
 
 describe('PreviewPane guest external handoff', () => {

apps/desktop/src/app/chat/right-rail/preview-pane.tsx

@@ -187,6 +187,20 @@ function isModuleMimeError(message: string): boolean {
   return lower.includes('failed to load module script') && lower.includes('mime type')
 }
 
+/**
+ * #101880: a guest page's `window.print()` (e.g. a Google Doc's Print
+ * button) reaches the macOS native print panel, whose construction
+ * segfaults inside PrintCore — the whole app dies before any dialog
+ * appears. Stub `print` in the guest so the native panel is never built;
+ * the warn surfaces in the preview console via the existing pipe. The
+ * `__hermesPrintGuard` flag keeps re-arms idempotent. Full print-to-PDF
+ * routing is the follow-up; this stops the crash.
+ */
+const PREVIEW_PRINT_GUARD_SCRIPT =
+  '(function(){if(window.__hermesPrintGuard)return;window.__hermesPrintGuard=true;' +
+  'window.print=function(){console.warn("[Hermes] Printing is disabled in the in-app preview. ' +
+  'Open the page in your browser to print.");};})()'
+
 function PreviewLoadError({
   consoleHeight = 0,
   error,
@@ -1175,6 +1189,15 @@ export function PreviewPane({
       notePage()
     }
 
+    // #101880: arm the print guard for every new guest document — a fresh
+    // load gets a fresh window object, so the stub must be re-injected.
+    const armPrintGuard = () => {
+      void webview.executeJavaScript?.(PREVIEW_PRINT_GUARD_SCRIPT)?.catch(() => {
+        // Guest tore down mid-arm (a navigation raced the injection) — the
+        // next dom-ready arms it again.
+      })
+    }
+
     // The WEBVIEW is the source of truth for DevTools, not our click handler:
     // closing the DevTools window itself fires devtools-closed with no click,
     // and the glyph was left stuck "on" when we tracked it locally.
@@ -1268,6 +1291,8 @@ export function PreviewPane({
     // SPAs title themselves long after the load settles, and a route change
     // renames the page without navigating at all.
     webview.addEventListener('page-title-updated', notePage)
+    // #101880: never let a guest reach the native print panel.
+    webview.addEventListener('dom-ready', armPrintGuard)
     host.appendChild(webview)
     webviewRef.current = webview
 
@@ -1284,6 +1309,7 @@ export function PreviewPane({
       webview.removeEventListener('did-start-loading', onStart)
       webview.removeEventListener('did-stop-loading', onStop)
       webview.removeEventListener('page-title-updated', notePage)
+      webview.removeEventListener('dom-ready', armPrintGuard)
       webview.remove()
       setAnnotate(session => (session.mode ? { ...endAnnotateMode(session), stack: emptyAnnotateStack() } : session))
     }