fix: await updatePodfile to prevent race condition during prebuild

[tarikfp]

What's happening

When running npx expo prebuild, the build randomly fails with:

❌ 'OneSignalFramework/OneSignalFramework.h' file not found

or

❌ 'OneSignalExtension/OneSignalExtension.h' file not found

The OneSignalNotificationServiceExtension target never gets added to the Podfile before pod install runs.

Related issues: #231

Why it happens

Two things are causing this:

1. The updatePodfile call isn't awaited

In withOneSignalIos.ts:

// not awaiting in order to not block main thread
const iosRoot = path.join(config.modRequest.projectRoot, "ios")
updatePodfile(iosRoot).catch(err => { OneSignalLog.error(err) });

The comment says it's intentional, but this causes prebuild to move on to pod install before the Podfile is updated.

2. The file write itself is async

In updatePodfile.ts:

fs.appendFile(`${iosPath}/Podfile`, NSE_PODFILE_SNIPPET, (err) => { ... });

Even if we awaited the function, fs.appendFile with a callback returns immediately.

The fix

withOneSignalIos.ts

- // not awaiting in order to not block main thread
- updatePodfile(iosRoot).catch(err => { OneSignalLog.error(err) });
+ await updatePodfile(iosRoot);

updatePodfile.ts

- fs.appendFile(`${iosPath}/Podfile`, NSE_PODFILE_SNIPPET, (err) => {
-     if (err) {
-         OneSignalLog.error("Error writing to Podfile");
-     }
- });
+ try {
+     fs.appendFileSync(`${iosPath}/Podfile`, NSE_PODFILE_SNIPPET);
+     OneSignalLog.log("OneSignalNotificationServiceExtension target added to Podfile.");
+ } catch (err) {
+     OneSignalLog.error("Error writing to Podfile: " + err);
+ }

Tested with

• onesignal-expo-plugin: 2.0.3
• expo: 53.0.0
• react-native: 0.79.6
• react-native-onesignal: 5.2.16
• Node.js: 22.19.0
• Xcode: 26.0.1

Before/After

Before:

$ npx expo prebuild --clean
$ grep "OneSignalNotificationServiceExtension" ios/Podfile
# nothing

$ npx expo run:ios
❌ 'OneSignalExtension/OneSignalExtension.h' file not found

After:

$ npx expo prebuild --clean
onesignal-expo-plugin: OneSignalNotificationServiceExtension target added to Podfile.

$ grep "OneSignalNotificationServiceExtension" ios/Podfile
target 'OneSignalNotificationServiceExtension' do

$ npx expo run:ios
✅ Build succeeds