MongoDB panache generates invalid update documents when updating a list or array with HQL

[languitar]

Describe the bug

When using the update method on a MongoDB panache entity with an HQL-like update description and a list or array parameter, the update fails, because an invalid update document is created.

Expected behavior

Arrays or lists of primitives can be updated using HQL or a proper exception is thrown in case this is not supported.

Actual behavior

The update fails with

2022-08-17 09:49:26,619 ERROR [org.jbo.res.rea.com.cor.AbstractResteasyReactiveContext] (executor-thread-0) Request failed: org.bson.json.JsonParseException: JSON reader was expecting ':' but found '}'.
	at org.bson.json.JsonReader.readBsonType(JsonReader.java:151)
	at org.bson.codecs.DocumentCodec.decode(DocumentCodec.java:178)
	at org.bson.codecs.DocumentCodec.decode(DocumentCodec.java:44)
	at org.bson.internal.LazyCodec.decode(LazyCodec.java:48)
	at org.bson.codecs.ContainerCodecHelper.readValue(ContainerCodecHelper.java:61)
	at org.bson.codecs.DocumentCodec.decode(DocumentCodec.java:180)
	at org.bson.codecs.DocumentCodec.decode(DocumentCodec.java:44)
	at org.bson.Document.parse(Document.java:127)
	at org.bson.Document.parse(Document.java:112)
	at io.quarkus.mongodb.panache.common.runtime.MongoOperations.executeUpdate(MongoOperations.java:762)
	at io.quarkus.mongodb.panache.common.runtime.MongoOperations.update(MongoOperations.java:753)
	at org.acme.TestEntity.update(TestEntity.java)
	at org.acme.GreetingResource.hello(GreetingResource.java:24)

How to Reproduce?

Reproduder: https://github.com/languitar/quarkus-mongodb-panache-update-list-reproducer

1. start the project in dev mode
2. curl -v http://localhost:8080/hello

Output of uname -a or ver

No response

Output of java -version

No response

GraalVM version (if different from Java)

No response

Quarkus version or git rev

2.11.2.Final

Build tool (ie. output of mvnw --version or gradlew --version)

No response

Additional information

Currently, if the list with the new values to set in the update operation contains only one element, the data in the database will be switched from an array to string, consequently breaking any further reads using the POJO.

All this happens, because PanacheQlQueryBinder expands a list into multiple comma-separated tokens, omitting the surrounding array square brackets:

PanacheQlQueryBinder.bindQuery(clazz, "list = ?1", new Object[] {Arrays.asList("test", "foo")})

results in:

{'list':'test', 'foo'}

[quarkus-bot]

/cc @FroMage, @evanchooly, @loicmathieu

[loicmathieu]

@languitar this indeed looks like a bug, I'll have a look.

[languitar]

Oh, btw, Maps will also not work:

[loicmathieu]

I just check the code and I'm not sure it's possible to update it. The code is shared between query document and update document.

For query document, if it's a native query the user must include the $in: [] and for PanacheQL query we add it.
See the following example from our test cases:

        List<Object> ids = Arrays.asList("f1", "f2");
        query = operations.bindFilter(DemoObj.class, "{ field: { '$in': [:fields] } }",
                Parameters.with("fields", ids).map());
        assertEquals("{ field: { '$in': ['f1', 'f2'] } }", query);

        List<Object> list = Arrays.asList("f1", "f2");
        query = operations.bindFilter(DemoObj.class, "field in ?1", new Object[] { list });
        assertEquals("{'field':{'$in':['f1', 'f2']}}", query);

If I change this it may break existing code, at least for the native query, we can deal with the PanacheQL change on our side. I agree that this is unfortunate for update document, maybe different mapping translation rules should be applied.

For your example, a query like this may work: list = [?1] or it may break our query parser.

As you notted, Map is currently not managed by our translation rules.

[loicmathieu]

Just checked and unfortunatly list=[?1] will not work, you need to use a native query like

 Bug27326Entity.update("{$set: {field : [?1]}}", List.of("one", "two", "three")).where("_id = ?1", bug27326Entity.id);

I keep it open for a while, maybe i'll come up with a solution but for now there is no other way than using a native query as to fix this we will need to break existing code that use collection parameters in a native query.

[languitar]

I just check the code and I'm not sure it's possible to update it. The code is shared between query document and update document.

Sounds like a different transformation is needed for the update part to get this working. If that is not a viable option, at least a more informative error message would be nice instead of a BSON parsing exception.