$id components of DBRef becoming String instead of MongoID

[tonymillion]

This has happened enough times to warrant logging here, I don't know if the problem is specifically Shanty or in the MongoDriver/DB (I'm running 2.0.2 for reference).

I have documents that have DBRefs in them, and sometimes I've noticed an exception being thrown in shanty when I update the DBRef, invariably when I look at the DB I find the $id component of the DBRef has become a String type instead of a ObjectId (MongoID).

E.g. (this just happened now)

"user": {
    "$ref": "users",
    "$id":"4f60ddde304fbee862000003"
  }

should be

"user": {
    "$ref": "users",
    "$id": ObjectId("4f60ddde304fbee862000003")
  }

As I said I haven't debugged it properly yet, but I'm raising this here incase anyone else has the issue.

[tonymillion]

For reference the exception is thown on line 938 of Mongo/Document.php where it tries to convert the mongoID into a string..

            if (MongoDBRef::isRef($newValue) && MongoDBRef::isRef($oldValue)) {
                $newValue['$id'] = $newValue['$id']->__toString();
                $oldValue['$id'] = $oldValue['$id']->__toString();

(which seems the wrong thing to do maybe?

[tholder]

Hi Tony,

Yes that does look dodgy to me. @coen-hyde might be able to give some insight in to this.

I haven't actually experienced this issue as yet but obviously this is nasty behaviour.

If you do want to attempt to fix it that would be great, will just need a pull request and the tests to be running.

Cheers Tom

[coen-hyde]

Oh nasty. That's strange code I wrote right there .....

By the looks of it the only reason i was converting ObjectId's to strings was for comparison. I don't think I meant to save the ObjectsId's as strings. I'd welcome a fix, a bit busy atm so can't fix it right now sorry.

Cheers, Coen

[tonymillion]

I'm not sure if thats exactly where the problem is occurring, but once it has happened, then the next time thats where the exception is thrown, as apparently string doesn't have a __toString() method….

[coen-hyde]

My bets are that's where it's happening.

[tholder]

Cool, I won't get much time until the weekend to look at it but I'll try and find a condition under which it occurs.

Cheers Tom

[tonymillion]

Yeah I just caught it again - its anytime a DBRef is reassigned to another DBRef (in my case the user that owns an object changed and it happened)

[tholder]

Cheers Tony, that helps. I might try and tackle it this afternoon.

[tonymillion]

I think I may have resolved this, and have to apologise:

I checked out our code and its been modified by from the original code base incorporating some things from @gwagner after he did a fix (from an earlier issue) for DBRefs not returning the right Object type when dereferenced.

for reference the code was

            /* arrays do not work the same way in evaluations */
            if(is_array($oldValue) && is_array($newValue))
            {
                if(json_encode($oldValue) !== json_encode($newValue))
                    $this->addOperation('$set', $property, $newValue);

            }
            elseif ($newValue !== $oldValue)
                $this->addOperation('$set', $property, $value);

(notice the use of newValue in the first addOperation I changed this back to value and it works, and also apparently MongoDBRef's pass the is_array test.)

Anyway I have reverted this change and it appears to have resolved the issue.

[tholder]

Hi Tony,

No worries.

I'm actually going to put a test in for this anyway, as it is obviously bad news for something like this to occur.

Cheers Tom