array value can't be queried if there's an index on the field

[askoog]

Given a database index on a field where the values are an array, it is not possible to find the document using an exact document template, you'll need to specify an $all option.

Example java code:

InMemoryMongoServer server = new InMemoryMongoServer();
server.bind();
MongoClient mongoClient = new MongoClient(new ServerAddress(server.getLocalAddress()));
MongoDatabase db = mongoClient.getDatabase("db");
MongoCollection<Document> collection = db.getCollection("coll");


collection.createIndex(new Document("key", 1), new IndexOptions().unique(true));
collection.insertOne(new Document("key", Arrays.asList("val1", "val2")));

// search for { "key" : [ "val1", "val2" ]}
FindIterable<Document> documents = collection.find(new Document("key", Arrays.asList("val1", "val2")));
List<Document> collect = StreamSupport.stream(documents.spliterator(), false).collect(Collectors.toList());
// no entries found
System.out.println(collect);

// search for { "key" : { "$all" : [ "val1", "val2" ]}}
documents = collection.find(new Document("key", new Document("$all", Arrays.asList("val1", "val2"))));
collect = StreamSupport.stream(documents.spliterator(), false).collect(Collectors.toList());
// finds the document
System.out.println(collect);

According to the mongo documentation, I'd expect the first query to also return the document, which is also the case if I skip the index creation.

A long shot guess is that the code handling index updates maybe also should create an entry for the array data as well?

Thanks for a great tool by the way!

[bwaldvogel]

Thanks for reporting this issue. It should be fixed with 36a4bb3. You could re-test with the latest version on main?

[bwaldvogel]

The fix is available in version 1.42.0.