fix(mobile): lazy env proxy so missing EXPO_PUBLIC vars throw inside React

apps/mobile/lib/env.test.ts

@@ -0,0 +1,30 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+describe('mobile env (lazy proxy)', () => {
+  beforeEach(() => {
+    vi.resetModules();
+    delete process.env.EXPO_PUBLIC_SUPABASE_URL;
+    delete process.env.EXPO_PUBLIC_SUPABASE_ANON_KEY;
+    delete process.env.EXPO_PUBLIC_AUTH_REDIRECT_URL;
+  });
+
+  it('importing the module does NOT throw when required vars are missing', async () => {
+    await expect(import('./env')).resolves.toBeTruthy();
+  });
+
+  it('reading a property with no env set throws a clear error', async () => {
+    const mod = await import('./env');
+    expect(() => mod.env.supabaseUrl).toThrowError(
+      /Missing required env var EXPO_PUBLIC_SUPABASE_URL/,
+    );
+  });
+
+  it('reading a property after setting env returns the value and memoises', async () => {
+    process.env.EXPO_PUBLIC_SUPABASE_URL = 'https://example.supabase.co';
+    process.env.EXPO_PUBLIC_SUPABASE_ANON_KEY = 'anon-123';
+    const mod = await import('./env');
+    expect(mod.env.supabaseUrl).toBe('https://example.supabase.co');
+    expect(mod.env.supabaseAnonKey).toBe('anon-123');
+    expect(mod.env.authRedirectUrl).toBe('netralax://auth/callback');
+  });
+});

apps/mobile/lib/env.ts

@@ -1,19 +1,41 @@
-// EXPO_PUBLIC_* vars are inlined at bundle time by Expo's Babel plugin.
-// We pull them through a single typed module so a missing var is a loud
-// startup error rather than a confusing Supabase 401 later.
+// EXPO_PUBLIC_* vars are inlined at bundle time by Expo's Babel plugin (or
+// shipped via EAS Secrets for EAS builds — see apps/mobile/README.md).
+// We pull them through a Proxy so missing vars throw on first READ, not at
+// module-eval time. That keeps the throw inside the React tree where the
+// <BootError> boundary can render it as a readable screen instead of a blank
+// white window.
 
 function required(name: string): string {
   const v = process.env[name];
   if (!v || v.length === 0) {
     throw new Error(
-      'Missing required env var ' + name + '. Set it in apps/mobile/.env.local — see .env.example.',
+      'Missing required env var ' + name +
+        '. Set it via `eas secret:create --scope project --name ' + name +
+        ' --value ...` or in apps/mobile/.env.local for local dev (see .env.example).',
     );
   }
   return v;
 }
 
-export const env = {
-  supabaseUrl: required('EXPO_PUBLIC_SUPABASE_URL'),
-  supabaseAnonKey: required('EXPO_PUBLIC_SUPABASE_ANON_KEY'),
-  authRedirectUrl: process.env.EXPO_PUBLIC_AUTH_REDIRECT_URL ?? 'netralax://auth/callback',
-} as const;
+interface EnvShape {
+  supabaseUrl: string;
+  supabaseAnonKey: string;
+  authRedirectUrl: string;
+}
+
+function readEnv(): EnvShape {
+  return {
+    supabaseUrl: required('EXPO_PUBLIC_SUPABASE_URL'),
+    supabaseAnonKey: required('EXPO_PUBLIC_SUPABASE_ANON_KEY'),
+    authRedirectUrl: process.env.EXPO_PUBLIC_AUTH_REDIRECT_URL ?? 'netralax://auth/callback',
+  };
+}
+
+let cached: EnvShape | null = null;
+
+export const env: EnvShape = new Proxy({} as EnvShape, {
+  get(_target, key: string | symbol): unknown {
+    cached ??= readEnv();
+    return cached[key as keyof EnvShape];
+  },
+});