I Had Claude Fable 5 Review My Indie Diary App Before It Got Pulled — The Bugs It Caught

Intro

I had Claude Fable 5 review and fix my Flutter diary app, Daily Diary (live on Google Play), before a release. This is a record of that.

Fable 5 was pulled worldwide just three days after launch (June 9 -> June 12, 2026) by a US Commerce Department export-control directive — but I got this pass in right before it went dark. Instead of generic "it caught what other models missed" claims, I'm pasting the actual diffs from my repo's commit history.

The app: Daily Diary

A simple offline diary app.

• 📱 Offline-first: data stays on the device, no cloud
• 🌐 5 languages: Japanese / English / Chinese / Korean / Spanish
• 🌙 Dark mode, 📅 calendar with mood indicators, 📊 stats (streaks, mood trends), 🔍 full-text search, 🎲 random past entry, 💾 JSON export/import
• Google Play: https://play.google.com/store/apps/details?id=com.diary.daily

Stack: Flutter 3.x / Dart, Provider, Hive (local NoSQL), Flutter intl.

What I asked for

Not "rewrite everything" — more like "find and fix what's questionable quality-wise": resolve flutter analyze warnings (there were 47), set up tests, add CI, update dependencies.

1. BuildContext used across an async gap

Several spots touched BuildContext (Navigator, localization) after an await. If the widget is disposed during the await, that throws. Fable inserted if (!mounted) return; right after the await:

   final db = DatabaseService();
   final existingEntry = await db.getEntryByDate(_selectedDate);
+  if (!mounted) return;

   final result = await Navigator.push(
     context,

You rarely hit this in normal use, so it's easy to miss even when testing yourself.

2. Hoisting the l10n lookup before the await

In the import handler _importData, AppLocalizations.of(context) (localized strings) was looked up repeatedly after awaits. It got hoisted to a single lookup before the first await, with a mounted guard before showing the confirmation dialog:

       _isImporting = true;
     });
+
+    final l10n = AppLocalizations.of(context)!;

     try {
       final result = await FilePicker...
       ...
       if (file.bytes == null) {
-        final l10n = AppLocalizations.of(context)!;   // looked up after await
         throw Exception(l10n.fileReadError);
       }
       ...
-      final l10n = AppLocalizations.of(context)!;
+      if (!mounted) return;                            // guard before dialog

3. The test that tested nothing

The leftover template widget_test.dart referenced a non-existent MyApp and didn't even compile (= effectively zero tests). It was removed and replaced with 12 real tests for the model and Hive persistence:

removed test/widget_test.dart             (broken template)
added  test/diary_entry_test.dart   +49   (model serialization, etc.)
added  test/database_service_test.dart +92 (Hive-backed save/load)

"You think you have tests, you don't" is the scariest state to be in, so fixing this mattered most.

4. 47 analyzer warnings to zero

The headline one was the Color.withOpacity() deprecation (withValues is now preferred for color precision). 27 spots replaced:

-  color: Colors.white.withOpacity(0.1),
+  color: Colors.white.withValues(alpha: 0.1),

Plus removing the deprecated ColorScheme.background / onBackground, and migrating RadioListTile (groupValue / onChanged removed) to the RadioGroup ancestor API. dart fix --apply handled the mechanical ones; API migrations were done by hand.

5. Major dependency bumps

Bumped the main dependencies, with two breaking API changes:

-  google_mobile_ads: ^4.0.0
+  google_mobile_ads: ^9.0.0
-  share_plus: ^7.2.1
-  file_picker: ^8.1.4
+  share_plus: ^12.0.2
+  file_picker: ^11.0.2

share_plus: Share.shareXFiles(...) -> SharePlus.instance.share(ShareParams(...)).

-  await Share.shareXFiles(
-    [XFile(file.path)],
-    subject: fileName,
+  await SharePlus.instance.share(
+    ShareParams(
+      files: [XFile(file.path)],
+      subject: fileName,
+    ),
   );

file_picker: the instance API FilePicker.platform.pickFiles(...) became a static FilePicker.pickFiles(...).

-  final result = await FilePicker.platform.pickFiles(
+  final result = await FilePicker.pickFiles(

On the pins: share_plus 13 conflicts with file_picker 11, and file_picker 12 is beta-only — so I settled on share_plus 12 / file_picker 11.

6. Added CI

A new flutter-ci.yml runs flutter analyze + tests on push/PR, so the project can't slip back into the "broken test" state.

How it felt as a solo dev

Honestly, what Fable caught wasn't flashy features — it was the class of things I systematically don't check on my own:

• async-gap mounted -> only crashes on certain timing
• a broken test -> you think you have tests, you don't
• a pile of deprecations -> works now, breaks later
• stale dependencies -> major bumps get postponed out of fear of breaking changes

I can write the features myself, but "only fails under specific conditions," "are the tests actually testing anything," and "deprecated-API + dependency housekeeping" tend to slip without a dedicated reviewer. One thorough pass on that was genuinely useful for a side project.

There are limits too: device-UI-dependent behavior (ads, export/import sharing) can't be verified in CI — I still test that on a real device. Concept, design, device testing, store submission, and final review stay my job.

It's a shame it went dark after three days, but I'm glad I got this pass in before it did.

Daily Diary is live on Google Play — give it a try:

📱 https://play.google.com/store/apps/details?id=com.diary.daily