CODEWITHSUNDEEP
c#.netmongodbmongodb-.net-driver
Ralph Shillington
Ralph Shillington

Reputation: 21108

Adding OfType<T> on MongoCollection "breaks" the behaviour of UpdateOneAsync

I've run into what I can only understand to be a bug in the C# driver.

This gist illustrates the problem.

If I run

collection.UpdateOneAsync(
    "{ \"_id\" : ObjectId(\"5656277cd4d37b13b4e7e009\"), \"Addresses.Index\" : 4 },
    "{ \"$set\" : { \"Addresses.$\" : { \"_t\" : [\"Address\", \"EmailAddress\"], \"Index\" : 4, \"MailTo\" : \"[email protected]\" } } }")

I get the desired result.

If however I use the Builders to build the filter definition and update definition like so:

var filter = Builders<Person> .Filter .And(Builders<Person>.Filter.Eq(p => p.Id, person.Id), Builders<Person>.Filter.Eq("Addresses.Index", 4));

var update = Builders<Person>.Update.Set("Addresses.$", new EmailAddress { Index = 4, MailTo = "[email protected]" });

then I must change my call to update to be

await collection.OfType<Person>().UpdateOneAsync(filter, update);

and the call to OfType results in the wrong address being replaced.

Upvotes: 0

Views: 669

Answers (1)

i3arnon
i3arnon

Reputation: 116606

This is unrelated to the MongoDB C# driver, but it seems to be a bug in MongoDB itself when the type is used in the query.

You can see that this causes the same issue without using OfType, but specifying the type field explicitly (i.e. "_t"):

var filter = Builders<Person>.Filter.And(
    new BsonDocument("_t", "Person"),
    Builders<Person>.Filter.Eq(p => p.Id, person.Id), 
    Builders<Person>.Filter.Eq("Addresses.Index", 4));
var update = Builders<Person>.Update.Set(
    "Addresses.$", 
    new EmailAddress { Index = 4, MailTo = "[email protected]" });
await db.GetCollection<Person>("Objects").UpdateOneAsync(filter, update);

You can see the query this will generate with this piece of code:

Console.WriteLine(db.GetCollection<Person>("Objects").Find(filter));

And the query is the following which is perfectly correct:

{ "_t" : "Person", "_id" : ObjectId("5656356f64c22e5d38aeb92e"), "Addresses.4 }

Upvotes: 1

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