Inconsistent JIRA Service Desk REST API Pagination

Summary

The Pagination used in JIRA Service Desk REST API does not return consistent results

Environment

JIRA Service Desk REST API

Steps to Reproduce

1. Create a GET request for Customer Requests

   <baseURL>/rest/api-name/resource-name?start=0&limit=100
   

2. Observe the "size" from the result
   Results

     "size": 76,
     "start": 0,
     "limit": 100,
     "isLastPage": true,
   

3. Change the start to a higher value and re-send the GET request

4. <baseURL>/rest/servicedeskapi/request?start=20&limit=100
   

5. Observe the "size" from the result
   Results

     "size": 36,
     "start": 20,
     "limit": 100,
     "isLastPage": true,
   

6. Change the start to a higher value and re-send the GET request

7. <baseURL>/rest/servicedeskapi/request?start=30&limit=100
   

8. Observe the "size" from the result
   Results

     "size": 16,
     "start": 30,
     "limit": 100,
     "isLastPage": true,
   

Expected Results

From the above example, Pagination should return 56 and 46 respectively

Actual Results

Returned values are not 56 and 46 respectively

Notes

JIRA Service Desk REST API is still an experimental release as per this comment

Workaround

It seems that the Servicedesk api code actually skips “start” parameter amount of entires twice. So, if you add start=10, its actually doing start=20 internally. If you say start=100, its actually doing start=200.
In order to get it working correctly, you would need to use half of the value of the start parameter that you intend to use. For instance, I tried this : 
 

http://localhost:8080/jira792/rest/servicedeskapi/request?start=0&limit=10

and then

http://localhost:8080/jira792/rest/servicedeskapi/request?start=5&limit=10