I have a doubt in the defect lifecycle (specifically defect closure/ change the status of the defect raised).
I wanted to get clarity as to when a tester raises a defect/bug , if this happens to be a duplicate defect and not noticed by the tester ,its assigned to a developer . The developer finds that this is a duplicate defect raised , then in this case ,
What will be the status of the defect and who closes defect . Is it the developer or the tester?
I think the tester will only close defect ( Is my thought process correct ?)
The defect lifecycle varies in many organizations. Most often, I'd agree that the more likely scenario would be that the bug returns to the submitter and is closed by them. So in your scenario, the dev could provide notes and a link or reference to the first bug for the tester to review.
It's possible that the tester was seeing different behavior and wants to clarify that the root cause is the same, or that the bug really is a duplicate.
Developers can be very flexible on what they call a duplicate. The defect should be sent back to the originator so they get a chance to dispute the the fact that it is a duplicate or validate the issue doesn't occur when the other defect is resolved.
Generally speaking I make every defect that is closed go through QA at some point (regardless of how it is resolved or who originated it). This guaratees that every change associated to a defect gets a test impact assessment. It really helps prevent those pesky marketing/development people from putting in a defect and getting it resolved without proper testing.
We have a status of "No Action Required" for defects that are not going to be fixed and one of the reasons for this can be "Duplicate of defect xxxxx". This is set by the developer and then the tester reviews the duplicate. If the tester agrees, then the defect goes to "Closed without action". If the tester disagrees, then a reason for the disagreement is sent to the developer and the defect is set back to its initial state.
Fixed defects go to "Closed". This allows me to review the number of duplicate defects as set to "Closed without action" and if there is a pattern I can change our process to reduce these defects being raised. Quite useful.