Backup silently corrupts all servers/keys since #1196 — custom toEncodable disables .toJson(), objects serialized via toString()

[PeterSpiegler]

Title: Backup silently corrupts all servers/keys since #1196 — custom toEncodable disables .toJson(), objects serialized via toString()

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Describe the bug

Since PR #1196 (first shipped in v1448), BackupV2.backup() passes a custom toEncodable to json.encode:

// lib/data/model/app/bak/backup2.dart:117
var result = json.encode(bak.toJson(), toEncodable: _toEncodable);

In Dart, providing a custom toEncodable replaces the encoder's default behavior of calling .toJson() on non-primitive objects. The fallback then stringifies everything that is not an Enum:

// lib/data/model/app/bak/backup2.dart:141-145
Object? _toEncodable(Object? value) {
  if (value is Enum) return value.name;
  _loggerV2.warning('Non-JSON-encodable type: ...');
  return value.toString();
}

Entries stored in Hive as typed objects (Spi, PrivateKeyInfo, snippets — via the adapters in lib/hive/hive_registrar.g.dart) end up in the backup as strings like "Spi<user@host:22>" instead of JSON objects, losing all credentials/settings at backup time.

On restore, these strings are dropped silently:

// lib/data/store/cached_store.dart:84-95 (_getAndConvert)
if (raw is Map) {
  try {
    final item = fromJson(Map<String, dynamic>.from(raw));
    ...
  } catch (e) {
    dprint('Parsing $T from JSON', e);   // debug-only
  }
}
return null;   // String entries are skipped without any user-visible error

WebDAV/iCloud sync uses the same BackupV2 path (lib/core/sync.dart) and is equally affected.

To Reproduce

1. On v1448+ (tested with v1450), have servers stored (create some, open the server list once)
2. Go to Settings → Backup, create a backup (file or WebDAV)
3. Restore this backup on another device (or after clearing data)
4. See empty server list, keys, and snippets — without any error message

Desired Results

Backup contains all servers/keys/snippets as JSON objects; restore brings them back. If serialization or parsing of an entry fails, the user is informed instead of data being dropped silently.

Actual Results

Every entry under spis/keys in the backup is a String (e.g. "Spi<user@host:22>"), not a JSON object — verified by decrypting a v1450 backup externally per Cryptor's AES-GCM/PBKDF2 format: 68/68 server entries corrupted. Restore completes without any visible error, but everything is empty. A backup created with v1426 (before #1196) contains proper JSON objects and restores fine, even on v1450.

Screenshots

Decrypted v1450 backup (external check):

spis: 68 Eintraege
mbx03741620: PROBLEM -> Typ ist str, kein dict!  ("Spi<user@host:...")
mbx06b21ee9: PROBLEM -> Typ ist str, kein dict!
...

Device

• OS: Android 16
• App Version: 1.0.1450 (bug present since 1.0.1448; 1.0.1426 works)

Additional context

Regression introduced by #1196 (18 Jun 2026), which was meant to fix the AppTab enum crash (#1194) but converted a loud failure into silent data corruption for all typed objects.

Suggested fix: in _toEncodable, try (value as dynamic).toJson() before falling back to toString() (or serialize stores explicitly via their models' toJson). Independently, CachedHiveStore._getAndConvert should surface skipped/unparsable entries to the user.

[coderabbitai]

🔗 Related PRs

#1107 - feat(Sync): Added app settings sync option [merged]
#1120 - Show iCloud backup status metadata [merged]
#1196 - Fix backup and restore format exception [merged]

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[GT-610]

Investigating.

[GT-610]

Here are Android builds that might fix your issue. Could you help us check out if the issue still exists?

Builds are from https://github.com/lollipopkit/flutter_server_box/actions/runs/28762478748, but they're over 25MB and can't be uploaded directly to GitHub, so I uploaded them elsewhere.

64-bit Arm: https://buzzheavier.com/t76unjohigar
32-bit Arm: https://buzzheavier.com/yxklk9jpdrsr
x86: https://buzzheavier.com/jdfqcpl24brm