Storing and retrieving documents changes their type signature

[olifly]

Hi.

When localstore stores a document it also saves the document to memory for faster retrieval. The problem is that in doing so it makes the types returned by a cached document vs uncached documents to be different and thereby breaking json marshal/unmarshal.

The following code should demonstrate this problem:

class JsonInner {
  final String val1;
  final bool val2;

  JsonInner(this.val1, this.val2);
  JsonInner.fromJson(Map<String, dynamic> json): this(json['val1'],json['val2']);
  
  Map<String, dynamic> toJson() => {
        'val1': val1,
        'val2': val2,
      };
}
class JsonOuter {
  final JsonInner inner;

  JsonOuter(this.inner);
  JsonOuter.fromJson(Map<String, dynamic> json): this(JsonInner.fromJson(json['inner']));

  Map<String, dynamic> toJson() => {
    'inner': inner,
  };  
}

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  final db = Localstore.instance;

  JsonOuter ob1 = JsonOuter(JsonInner("Inner", true));
  String key = "uno";
  String collectionName = "deus";

  var data = await db.collection(collectionName).doc(key).get();
  if(data == null) {
    log("Data is null. Storing");
    db.collection(collectionName).doc(key).set(ob1.toJson());
    log("Data stored. Now run me again!!");
    return;
  } else {
    log("We got data: $data");
    log("Unmarshalling the data to an object will work");
    log("Unmarshal: ${JsonOuter.fromJson(data).toString()}");
    log("Storing again and retrieving");
    db.collection(collectionName).doc(key).set(ob1.toJson());
    data = await db.collection(collectionName).doc(key).get();
    log("Data is now: $data");
    log("Unmarshalling the data to an object will fail because type of 'inner' is not the same as when you read from file");
    log("Unmarshal: ${JsonOuter.fromJson(data!).toString()}");
  }
}

[ekasetiawans]

You have to use inner.toJson in JsonOuter.toJson too