A software bug is defined as an error or failure or fault in a system or computer program that produces an unexpected or incorrect result. This is applicable for any Drupal/non-Drupal website. The bug life cycle in a Drupal website consists of steps from identification to closure of a bug. Different stages of Bug Life Cycle are:
New: When a tester posts a bug its status is New.
Opened: New bug yet to be approved. So when the test leader approves it, its status changes to open.
Assigned: When the test lead assign the bug to the corresponding developer , its status changes to Assigned.
Rejected: Sometimes the developer feel that the bug is not genuine. So the developer rejects the bug and then the status of the bug becomes Rejected.
Test: When the developer fixes the bug and sends it for testing, the status of the bug changes to Testing.
Reassigned: If the tester found that the bug still exists or partially fixed, he send it back to the developer. Then the status of the bug is Reassigned.
Closed: Once the bug is verified and assured that the bug no longer exists, its status changes to Closed.
Reopened: If the issue still comes again, the tester change the status of the bug to reopened and the bug has to go all the above phases again.
Deferred: If the bug is decided to be fix in the next version, the status of the bug is changes to Deferred.