Behavioral Interview Question: How would you approach debugging a complex issue in a large codebase?Situation: As a software engineer, I have faced many instances where I have had to debug complex issues in a large codebase.Task: To efficiently debug and resolve a complex issue in a large codebase.Action: My approach to debugging a complex issue in a large codebase involves the following steps:Step 1: Reproducing the issue

• I begin by trying to reproduce the issue on my local machine so I can understand the steps leading up to the error.
• I read relevant logs and error messages to understand the issue.
• I use debugging tools to see the state of variables, stack traces, and other relevant information.

Step 2: Narrowing down the root cause

• Once the issue has been reproduced, I try to narrow down the scope of the issue and identify the root cause.
• I start by scrutinizing the code in and around the error, including any dependencies or related code which can impact the issue.
• Utilizing the "binary search" method, I inspect the code changes chronologically to identify if any recent commits/backend changes could have caused the problem.

Step 3: Debugging the issue

• Once I have identified the root cause, I start debugging by inserting logs in specific areas of the codebase.
• I confirm returned values and verify if they meet the expectations of the code.
• I also use code review sessions to bounce off the issue and have a team member go through the code with a fresh perspective.
• If the issue is very complex, I spend time researching forums, stack overflows, and other resources to find any previously encountered issues that are similar to tackle the problem.

Step 4: Testing and Deploying

• Once all possible bugs have been fixed, I test to ensure that the changes did not impact other areas of the codebase, including any edge cases.
• I then deploy the fix to the production environment and monitor it for further issues.

Result: Following this approach will greatly increase the chances of a swift resolution to a complex issue in a large codebase.
Relevant Citations:

• Debugging Techniques Every Programmer Should Know
• What is a Debugger?
• The Art of Debugging