GPMONGODB-138: Modifications of embedded Lists are not saved when it is the only change in the object

[graemerocher]

Original Reporter: ziftytodd
Environment: Grails 2.0.0.RC1, OS X 10.7.2
Version: 1.0.0.RC1
Migrated From: http:https://jira.grails.org/browse/GPMONGODB-138

If you load an object, only add something to an embedded list in that object and do a save, the change to the embedded list is not saved if nothing else on the object changed. However, if you change a simple field on the object as well, then the change in the list is saved. For example:

{code:title=Author.java|borderStyle=solid}
class Author {
String id
String name
List books
Integer meaninglessField = 1
static hasMany = [ books : Book ]
static embedded = [ 'books' ]
}
{code}

{code:title=Book.java|borderStyle=solid}
class Book {
String title
String toString() { title }
}
{code}

{code:title=AuthorController.java|borderStyle=solid}
class AuthorController {
def addBookToAuthor() {
Author author = Author.get(params.id)
Book book = new Book(params)
author.books << book
log.info "in memory instance contains the added book: ${author.books}"
author.save(flush:true)

  Author loadedAuthor = Author.get(params.id)
  log.info "loading from mongo again shows the new book didn't get saved: ${loadedAuthor.books}"     

}

def addBookAndChangeAuthor() {
Author author = Author.get(params.id)
Book book = new Book(params)
author.books << book
author.meaninglessField++
author.save(flush:true)

  Author loadedAuthor = Author.get(params.id)
  log.info "loading from mongo again shows the new book did get saved when updating another field too: ${loadedAuthor.books}"     

}
}
{code}