fix(desktop): only show Local Network guidance on macOS 15+

Author: waleedlatif1

apps/desktop/src/main/load-health.test.ts

@@ -8,10 +8,9 @@ describe('classifyLoadError', () => {
     expect(classifyLoadError(-1)).toBe('unreachable')
   })
 
-  it('reports ERR_ADDRESS_UNREACHABLE as a local-network block only on macOS', () => {
-    expect(classifyLoadError(-109, 'darwin')).toBe('local_network')
-    expect(classifyLoadError(-109, 'linux')).toBe('unreachable')
-    expect(classifyLoadError(-109, 'win32')).toBe('unreachable')
+  it('reports ERR_ADDRESS_UNREACHABLE as a local-network block only under Local Network privacy', () => {
+    expect(classifyLoadError(-109, true)).toBe('local_network')
+    expect(classifyLoadError(-109, false)).toBe('unreachable')
   })
 })
 

apps/desktop/src/main/load-health.ts

@@ -1,3 +1,4 @@
+import { release } from 'node:os'
 import { createLogger } from '@sim/logger'
 import type { BrowserWindow } from 'electron'
 import { type EventRecorder, scrubUrl } from '@/main/observability'
@@ -6,6 +7,15 @@ const logger = createLogger('DesktopLoadHealth')
 
 const AUTO_RETRY_INTERVAL_MS = 5000
 const LOAD_WATCHDOG_MS = 30_000
+/** Darwin 24 is macOS 15, the first release that gates apps behind Local Network privacy. */
+const FIRST_LOCAL_NETWORK_PRIVACY_DARWIN = 24
+
+function hasLocalNetworkPrivacy(): boolean {
+  return (
+    process.platform === 'darwin' &&
+    Number.parseInt(release(), 10) >= FIRST_LOCAL_NETWORK_PRIVACY_DARWIN
+  )
+}
 
 export type LoadErrorKind =
   | 'offline'
@@ -22,7 +32,7 @@ export type LoadErrorKind =
  */
 export function classifyLoadError(
   errorCode: number,
-  platform: NodeJS.Platform = process.platform
+  localNetworkPrivacy: boolean = hasLocalNetworkPrivacy()
 ): LoadErrorKind {
   // Only ERR_ABORTED (-3) and success (0) are ignored. ERR_FAILED (-2) and
   // ERR_IO_PENDING (-1) are real failures that must surface the offline page.
@@ -44,7 +54,7 @@ export function classifyLoadError(
   // macOS Local Network privacy fails the socket with EHOSTUNREACH, which
   // Chromium reports as ERR_ADDRESS_UNREACHABLE (-109), so a self-hosted server
   // on a private address looks like a routing failure until Sim is allowed.
-  if (errorCode === -109 && platform === 'darwin') {
+  if (errorCode === -109 && localNetworkPrivacy) {
     return 'local_network'
   }
   return 'unreachable'