scalikejdbc/scalikejdbc — pull request #305 by seratch (2014-10-28 05:51:35+00:00)
Title: Remove default TxBoundary typeclass instances

In the following case, DB connection will be uselessly grasped by localTx's `TxBoundary` control if it's enabled by default since 2.2.

```scala
DB.localTx { implicit s =>
// works with the DB connection
...
doFutureOperation()
}

def doFutureOperation()(implicit ctx: ExecutionConttext): Future[Something] = {
Future {
// Assumes this block sometimes takes long time due to other operations (e.g. external API call).
// Although this code probably should be outside of this localTx block ideally,
// the author of code might think it's safe because this Future ops won't join the transaction
}
}
```

If there is a risk that existing applications may be in trouble, we should keep backward compatibility after 2.2 release too.