Problems with Version 1.2 - support for Mongo 3.0

[mantithetical]

JaversBuilder.javers().registerJaversRepository(mongoRepo).build() throws

com.mongodb.CommandFailureException: { "serverUsed" : "myDb:27017" , "ok" : 0.0 , "errmsg" : "unauthorized"}
    at com.mongodb.CommandResult.getException(CommandResult.java:76)
    at com.mongodb.CommandResult.throwOnError(CommandResult.java:140)
    at com.mongodb.DB.eval(DB.java:464)
    at org.javers.repository.mongo.MongoRepository.ensureSchema(MongoRepository.java:139)
    at org.javers.core.JaversBuilder.build(JaversBuilder.java:90)

The root cause appears to be the unauthorized migration in ensureSchema:

//schema migration script from 1.1 to 1.2
        BSONObject doc = snapshots.findOne();
        if (doc != null) {
            Object stringCommitId = ((Map)doc.get("commitMetadata")).get("id");
            if (stringCommitId instanceof String) {
                mongo.eval("db.jv_snapshots.find().forEach(function(snapshot){snapshot.commitMetadata.id = Number(snapshot.commitMetadata.id);db.jv_snapshots.save(snapshot);});");
            }
        }

The eval method has been deprecated as of mongodb version 3.0

I bypassed this issue by running the migration manually. However, after the first commit, subsequents commits throw a class cast exception.

javers.commit(username, myObject) throws

Caused by: java.lang.ClassCastException: java.lang.Object cannot be cast to java.lang.String
    at org.javers.core.metamodel.object.CdoSnapshotBuilder.withChangedProperties(CdoSnapshotBuilder.java:92)
    at org.javers.core.json.typeadapter.commit.CdoSnapshotTypeAdapter.deserializeChangedProperties(CdoSnapshotTypeAdapter.java:68)
    at org.javers.core.json.typeadapter.commit.CdoSnapshotTypeAdapter.fromJson(CdoSnapshotTypeAdapter.java:53)
    at org.javers.core.json.typeadapter.commit.CdoSnapshotTypeAdapter.fromJson(CdoSnapshotTypeAdapter.java:22)
    at org.javers.core.json.JsonConverterBuilder$2.deserialize(JsonConverterBuilder.java:139)

[bartoszwalacik]

Both problems are caused by API changes in MongoDB. As far as I know, MongoDB 3.0 is not compatible with 2.x. Currently, Javers works with Mongo 2.6. I don't have quick solution how to support both Mongo versions in the same time. If we switch Javers to Mongo 3.0, it would brake existing clinets who use Mongo 2.x. Any ideas how to solve this?

[bartoszwalacik]

think I should switch javers-persistence-mongo from MongoDB 2.6 to 3.0

[mantithetical]

The driver version up to 2.12.* seems to work fine. Anything after that is problematic. Switching to 3.0 sounds like a good idea.

[bgalek]

We decided to update mongo in javers-mongo-repository project, so it will support mongo 3, everyone still using older mongo will have to stick with javers-mongo-repository 1.2, stay tuned!

[mantithetical]

I am using mongo 2.6 and getting the Object to String class cast exception on javers commits. Don't you think that needs to be fixed? Otherwise, no one can use version javers 1.2.0.

[bartoszwalacik]

so you are using Mongo 2.6 or 3.0?
After running the migration script manually, what types you have under jv_snapshots.commitMetadata.id?

It should be changed from String do double, JaVers 1.2.0 expects doubles here

[mantithetical]

I am using Mongo 2.6 locally. I dropped both javers collections, so it's a fresh start. The first javers commit works fine as one would expect. Any subsequent commit fails with the ClassCastException. The problem is with javers 1.2.0 only.

[bartoszwalacik]

it means serious problem, i'll check it asap

[bartoszwalacik]

that's confusing, I cannot reproduce this error on Mongo 2.6, could you send me first few documents from jv_snapshots collection ?

[bartoszwalacik]

and the full stack trace?

[bartoszwalacik]

I've checked if this bug occurs in our demo-app https://github.com/javers/javers-demo wich works with Mongo 2.6. App works fine. I cannot reproduce this bug

[mantithetical]

Let me get back to you with more details.