Pinning PFObject with pointer corrupts local datastore

[mtsanford]

Tested on version 1.9.1. If an object C1 pointing to P1 is pinned (and not saved), then an object C2 pointing to P2 is pinned, P1 is corrupted in the datastore. This seems to be the minimum condition to reproduce:

func letsCorruptTheDatastore(sender: AnyObject) {

        // create a post with a comment and pin it
        let post1 = PFObject(className:"Post")
        post1["text"] = "I am post #1"
        let comment1 = PFObject(className:"Comment")
        comment1["post"] = post1

        comment1.pinInBackground().continueWithSuccessBlock {
            (task: BFTask!) -> AnyObject! in

            // Make another post with comment and pin it
            let post2 = PFObject(className:"Post")
            post2["text"] = "I am post #2"
            let comment2 = PFObject(className:"Comment")
            comment2["post"] = post2
            return comment2.pinInBackground()
        }.continueWithSuccessBlock {
            (task: BFTask!) -> AnyObject! in

            // Now try to query local Post objects
            let query = PFQuery(className:"Post")
            query.fromLocalDatastore()
            return query.findObjectsInBackground()
        }.continueWithBlock {
            (task: BFTask!) -> AnyObject! in
            if (task.error != nil) { print(task.error) }
            else if (task.result != nil) { print(task.result) }
            return nil 
        } 
    }

The query fails with this error:

Error Domain=Parse Code=120 "Attempted to fetch and object offline which was never saved to the offline cache" UserInfo={error=Attempted to fetch and object offline which was never saved to the offline cache, code=120, NSLocalizedDescription=Attempted to fetch and object offline which was never saved to the offline cache}

Looking at the sqlite database, it is apparent that the data has been corrupted (nulled out), which results in queries on the corrupted data always failing.

sqlite> 
sqlite> select * from ParseObjects where className = "Post";
41067A2D-5BE8-4BD8-8902-C453E790C69B|Post||{"className":"Post","__complete":true,"__operations":[{"__updatedAt":{"iso":"2015-11-10T16:58:07.687Z","__type":"Date"},"__uuid":"FD2A80A9-7E9F-469E-95DC-2DF4A0014361","text":"I am post #2"}],"isDeletingEventually":0}|0
616B0182-1A5B-4F44-BE05-204A80AAE557|Post|||0
sqlite> select * from ParseObjects where className = "Comment";
B847E0D4-725A-464D-AEA9-51D4CADCD66A|Comment||{"className":"Comment","__complete":true,"__operations":[{"__updatedAt":{"iso":"2015-11-10T16:58:07.691Z","__type":"Date"},"post":{"uuid":"616B0182-1A5B-4F44-BE05-204A80AAE557","__type":"OfflineObject"},"__uuid":"546E9AEF-63B7-460A-A130-BD547D11DB45"}],"isDeletingEventually":0}|0
AB5FAF2A-C698-4A4F-8011-1FC3602247D3|Comment||{"className":"Comment","__complete":true,"__operations":[{"__updatedAt":{"iso":"2015-11-10T16:58:07.688Z","__type":"Date"},"post":{"uuid":"41067A2D-5BE8-4BD8-8902-C453E790C69B","__type":"OfflineObject"},"__uuid":"D58AAEEE-093F-4C71-B002-F6F10B3E05D5"}],"isDeletingEventually":0}|0
sqlite> 

[mtsanford]

digging a little deeper, it appears that first pin is not even done correctly, and that the bug is in pinning objects with pointers. After just saving a single Comment pointing to a Post, the sqlite database contains this data:

BD07816F-F2AA-4DC1-9807-BC191FCE58C8|_Pin||{"className":"_Pin","__complete":true,"__operations":[{"_objects":[{"uuid":"88B8BFB7-E56A-49E4-81FD-FC836897AE77","__type":"OfflineObject"}],"__uuid":"19FFB7FD-534F-4BFB-B6C8-EF17B16919C5","_name":"_currentUser","__updatedAt":{"iso":"2015-11-10T19:42:41.601Z","__type":"Date"}}],"isDeletingEventually":0}|0
88B8BFB7-E56A-49E4-81FD-FC836897AE77|_User||{"className":"_User","__complete":true,"__operations":[{"__uuid":"7A490326-1421-40B6-B867-EB13C346DA13","__updatedAt":{"iso":"2015-11-10T19:42:41.594Z","__type":"Date"}}],"isDeletingEventually":0}|0
7A2C3F1F-9DB7-4566-AFE1-0C26D02ABC1F|_Pin||{"className":"_Pin","__complete":true,"__operations":[{"_objects":[{"uuid":"8F91E10D-80CD-43DE-86E7-EFCB8BC81F88","__type":"OfflineObject"}],"__uuid":"24E5AEE3-1417-4BDE-A129-59907AA22574","_name":"_default","__updatedAt":{"iso":"2015-11-10T19:43:21.446Z","__type":"Date"}}],"isDeletingEventually":0}|0
9DD18DC7-D153-469A-8636-3DF1B5CA9B02|Post||{"className":"Post","__complete":true,"__operations":[{"__updatedAt":{"iso":"2015-11-10T19:43:21.443Z","__type":"Date"},"__uuid":"4242605C-52D6-4709-B02C-C42423C3B5E7","text":"I am another post"}],"isDeletingEventually":0}|0
8F91E10D-80CD-43DE-86E7-EFCB8BC81F88|Comment||{"className":"Comment","__complete":true,"__operations":[{"__updatedAt":{"iso":"2015-11-10T19:43:21.443Z","__type":"Date"},"post":{"uuid":"9DD18DC7-D153-469A-8636-3DF1B5CA9B02","__type":"OfflineObject"},"__uuid":"FC33D3E3-B185-45D3-B17C-EE26971B62E4"}],"isDeletingEventually":0}|0
sqlite> 

The second pin (7A2C3F1F...) appears to include the Comment (8F91E10D...) in it's list of objects, but not the Post it points to (9DD18DC7...). Although maybe I'm not fulling understanding how pinning is implemented.

In the documentation it states: "Pinning a PFObject is recursive, just like saving, so any objects that are pointed to by the one you are pinning will also be pinned. "

[richardjrossiii]

This seems related to #239, though I don't have the slightest clue what could be causing this.

LocalDataStore is a very complex beast. and it's very possible there exists a pointer encoding bug there. I'll look into it.

And - thank you for the super clear repro case, it makes investigating this super easy.

[mtsanford]

OK, thanks. It looks like explicitly pinning referenced objects is a good workaround for now.

[henrikperrochon]

Hi,
I've faced the same issue. I've used another workaround which is pinning with specific name.
Have a nice day!

I have this problem too and I am already pinning with specific names. My object contains pointers that have pointers to other objects. When I initially pin them, they save correctly. But if I pin another object of the same type, they are all removed, and querying the local datastore returns nothing.

[maricabertarini]

Hi,
any news? I am experiencing the same on Android. I pin in bg an object that contains an array of pointers. Then, when I query for this kind of objects and I use include to retrieve pointers, I get error with code 120 and message Message: This object is not available in the offline cache.
Thanks for your help!

[gloos]

Same issue here.

same issue here, really need a solution for that

[swapsjadhav]

Any update on this issue?

[CiraciNicolo]

+1

[ranhsd]

+1

[edson-gaspar]

I'm sad with Parse local store. I need to finish an App ASAP and its very danger to persist my objects to sync later. Now I'm trying to implement my offline storage with IBM Cloudant or RealmSwift constructing a bridge on models to sync with Parse when data is committed. Please, could someone have another idea or its a good start?

[CiraciNicolo]

Can you at least give us some info?