Default order of records is not -last_modified

[leplatrem]

While writing kinto-client integration we noticed that creating a list of records using a batch requests didn't preserve the passed order.

[leplatrem]

Bug confirmed implicit sort order -last_modified is not enabled

Create batch of records:

echo '{"defaults":{"headers":{"Authorization":"Basic dXNlcjpwYXNz"}},"requests":[{"method":"PUT","headers":{"If-None-Match":"*"},"path":"/v1/buckets/default/collections/blog/records/d914797f-1e55-4dde-ac92-51f4d06ba990","body":{"data":{"id":"d914797f-1e55-4dde-ac92-51f4d06ba990","title":"art1"}}},{"method":"PUT","headers":{"If-None-Match":"*"},"path":"/v1/buckets/default/collections/blog/records/8aadb4d4-c107-4335-a119-81027143cf22","body":{"data":{"id":"8aadb4d4-c107-4335-a119-81027143cf22","title":"art2"}}},{"method":"PUT","headers":{"If-None-Match":"*"},"path":"/v1/buckets/default/collections/blog/records/8712d6c9-8caf-43d3-b70d-7c82d672a1bc","body":{"data":{"id":"8712d6c9-8caf-43d3-b70d-7c82d672a1bc","title":"art3"}}}]}' | http POST http://localhost:8888/v1/batch

Retrieve:

http GET ":8888/v1/buckets/default/collections/blog/records" --auth user:pass
HTTP/1.1 200 OK
Access-Control-Expose-Headers: Content-Length, Expires, Alert, Retry-After, Last-Modified, Total-Records, ETag, Pragma, Cache-Control, Backoff, Next-Page
Cache-Control: no-cache
Content-Length: 283
Content-Type: application/json; charset=UTF-8
Date: Wed, 10 Feb 2016 14:53:32 GMT
Etag: "1455115734732"
Last-Modified: Wed, 10 Feb 2016 14:48:54 GMT
Server: waitress
Total-Records: 3

{
    "data": [
        {
            "id": "8aadb4d4-c107-4335-a119-81027143cf22", 
            "last_modified": 1455115734728, 
            "title": "art2"
        }, 
        {
            "id": "d914797f-1e55-4dde-ac92-51f4d06ba990", 
            "last_modified": 1455115734725, 
            "title": "art1"
        }, 
        {
            "id": "8712d6c9-8caf-43d3-b70d-7c82d672a1bc", 
            "last_modified": 1455115734732, 
            "title": "art3"
        }
    ]
}

With order:

http GET ":8888/v1/buckets/default/collections/blog/records?_sort=-last_modified" --auth user:pass
HTTP/1.1 200 OK
Access-Control-Expose-Headers: Content-Length, Expires, Alert, Retry-After, Last-Modified, Total-Records, ETag, Pragma, Cache-Control, Backoff, Next-Page
Cache-Control: no-cache
Content-Length: 283
Content-Type: application/json; charset=UTF-8
Date: Wed, 10 Feb 2016 14:54:03 GMT
Etag: "1455115734732"
Last-Modified: Wed, 10 Feb 2016 14:48:54 GMT
Server: waitress
Total-Records: 3

{
    "data": [
        {
            "id": "8712d6c9-8caf-43d3-b70d-7c82d672a1bc", 
            "last_modified": 1455115734732, 
            "title": "art3"
        }, 
        {
            "id": "8aadb4d4-c107-4335-a119-81027143cf22", 
            "last_modified": 1455115734728, 
            "title": "art2"
        }, 
        {
            "id": "d914797f-1e55-4dde-ac92-51f4d06ba990", 
            "last_modified": 1455115734725, 
            "title": "art1"
        }
    ]
}

[ayusharma]

I want to work on this bug. I am able to reproduce the situation. Looking forward for suggestion to start.