.jsonDecode -> FormatException: Unexpected end of input (at character 1) ^. Error thrown

I keep facing same error seeing logs of firebase crashlytics.

.jsonDecode FormatException: Unexpected end of input (at character 1) ^. Error thrown .

.jsonDecode (dart:convert) JsonCacheInfoRepository._readFile (json_cache_info_repository.dart:143) JsonCacheInfoRepository.open (json_cache_info_repository.dart:40) _WebSocketConsumer.close.. (dart:_http) CacheStore._getCacheDataFromDatabase (cache_store.dart:112) CacheStore.retrieveCacheData. (cache_store.dart:73)

As you can see from thread of this error, it points to cache part.

I use data as decoding it from shared preference:

Future<dynamic> requestCacheDioDiaryGroup(
    String uri, int page, Map<String, dynamic> requestBody) async {
  try {
    final uriKey = "$uri-$page";

    bool exists = SharedPrefsHelper.prefs.containsKey(uriKey);

    if (exists) {
      final data = SharedPrefsHelper.prefs.getString(uriKey);
      if (data != null) {
        return jsonDecodeSafe(data);
      }
    } else {
      String requestBodyJson = jsonEncode(requestBody);
      final tokenHeaders = await firebaseTokenHeaders();

      final response = await http.post(
        Uri.parse(uri),
        body: requestBodyJson,
        headers: tokenHeaders,
      );

      if (response.statusCode == 200) {
        Map<String, dynamic> data =
            jsonDecodeSafe(utf8.decode(response.bodyBytes));

        final diary = data["data"];

        // prefs 저장
        final jsonList = jsonEncode(diary);
        await SharedPrefsHelper.prefs.setString(uriKey, jsonList);
        return diary;
      }
    }
  } catch (e) {
    // ignore: avoid_print
    print("[dio] requestCacheDioDiaryGroup error: $e");
  }
}

And I used jsonDecodeSafe code, not general jsonDecode due to this error:

T jsonDecodeSafe<T>(String? source,
    {String tag = "json_tag", int sample = 120}) {
  try {
    final s = source?.trim();
    if (s == null || s.isEmpty) {
      FirebaseCrashlytics.instance
          .log('[jsonDecodeSafeSafe] EMPTY_INPUT tag=$tag');
      FirebaseCrashlytics.instance.setCustomKey('json_tag', tag);
      FirebaseCrashlytics.instance.setCustomKey('json_len', s?.length ?? 0);
      FirebaseCrashlytics.instance
          .setCustomKey('json_sample', (s ?? '').substring(0, 0));
      throw const FormatException('Empty JSON input');
    }
    // 간혹 UTF-8 디코딩 이슈/잘린 바디 방지용
    final decoded = json.decode(s);
    return decoded as T;
  } catch (e, st) {
    // 앞부분 샘플만 남겨서 개인정보/대용량 로그 방지
    final sampleStr = (source ?? '').replaceAll('\n', ' ');
    FirebaseCrashlytics.instance.setCustomKey('json_tag', tag);
    FirebaseCrashlytics.instance.setCustomKey('json_len', source?.length ?? 0);
    FirebaseCrashlytics.instance.setCustomKey('json_sample',
        sampleStr.substring(0, sample.clamp(0, sampleStr.length)));
    FirebaseCrashlytics.instance
        .recordError(e, st, reason: 'jsonDecodeSafeSafe failed ($tag)');
    rethrow; // Crashlytics에 남긴 뒤 원래 흐름 유지(또는 적절히 처리)
  }
}

I changed all jsonDecode to jsonDecodeSafe in my project in order to prevent this error.

However users keep facing this error.