Bug life cycle

What is Bug/Defect?

Simple Wikipedia definition of Bug is: “A computer bug is an error, flaw, mistake, failure, or fault in a computer program that prevents it from working correctly or produces an incorrect result. Bugs arise from mistakes and errors made by people, in either a program’s source code or its design.”

Other definitions can be:

An unwanted and unintended property of a program or piece of hardware, especially one that causes it to malfunction.


A fault in a program, which causes the program to perform in an unintended or unanticipated manner.

Lastly, the general definition of a bug is: “failure to conform to specifications”.

If you want to detect and resolve the defect in early development stage, defect tracking and software development phases should start simultaneously.

We have discussed more on Writing effective bug report in another article. Let’s concentrate here on bug/defect life cycle.

The life cycle of Bug:

1) Log new defect

The mandatory fields when a tester logs any new bug are Build version, Submit On, Product, Module, Severity, Synopsis and Description to Reproduce

In above list, you can add some optional fields if you are using manual Bug submission template. These Optional Fields include Customer name, Browser, Operating system, File Attachments or screenshots.

The following fields remain either specified or blank:

If you have authority to add bug Status, Priority and ‘Assigned to’ fields then you can specify these fields. Otherwise, Test manager will set status, Bug priority and assign the bug to the respective module owner.

Look at the following Bug life cycle:

[Click on the image to view full size] Ref: Bugzilla bug life cycle

The figure is a quite complicated one but when you consider the significant steps in bug life cycle you will get a quick idea of bug life.

On successful logging, the bug is reviewed by Development or Test manager. Test manager can set the bug status as Open, can Assign the bug to developer or bug may be deferred until next release.

When a bug gets assigned to a developer and he/she can start working on it. The developer can set bug status as won’t fix, Couldn’t reproduce, Need more information or ‘Fixed’.

If the bug status set by the developer is either ‘Need more info’ or Fixed then the QA responds with a specific action. If the bug is fixed then QA verifies the bug and can set the bug status as verified closed or Reopen.

Bug status description:

These are various stages of bug life cycle. The status caption may vary depending upon the bug tracking system you are using.

1) New: When QA files a new bug.

2) Deferred: If the bug is not related to a current build or cannot be fixed in this release or bug is not important to fix immediately then the project manager can set the bug status as deferred.

3) Assigned: ‘Assigned to’ field is set by a project lead or manager and the bug is assigned to a developer.

4) Resolved/Fixed: When a developer makes necessary code changes and verifies the changes then he/she can make bug status as ‘Fixed’ and then the bug is passed to the testing team.

5) Could not reproduce: If a developer is not able to reproduce the bug by the steps given in bug report by QA then the developer can mark the bug as ‘CNR’. QA needs action to check if the bug is reproduced and can assign it to a developer with detailed reproducing steps.

6) Need more information: If a developer is not clear about the bug reproduce steps provided by QA to reproduce the bug, then he/she can mark it as “Need more information‘. In this case, QA needs to add detailed reproducing steps and assign bug back to dev for the fix.

7) Reopen: If QA is not satisfied with the fix and if the bug is still reproducible even after fix then QA can mark it as ‘Reopen’ so that developers can take appropriate action.

8 ) Closed: If the bug is verified by the QA team and if the fix is ok and the problem is solved then QA can mark the bug as ‘Closed’.

9) Rejected/Invalid: Sometimes the developer or team lead can mark the bug as Rejected or invalid if the system is working according to specifications and bug is just due to some misinterpretation.

Let us know your valuable suggestions/comments on this article.