7 Strategies: What to Take Care of Before Cleaning Up a Messy Codebase

Imagine diving into refactoring a massive codebase without a strategy—removing what seems unnecessary, renaming variables randomly, and restructuring code without testing. The result? Everything breaks, and no one knows why.

To avoid this nightmare, here are seven crucial steps to follow before cleaning up your codebase:

😱 Cleaning Up Without a Plan Can Break Everything

1. Understand the Codebase First

📌 Why? You can’t clean up what you don’t understand. Jumping into refactoring without knowing how different parts of the system work can lead to major regressions.

🔹 Actions to Take:

Read existing documentation (if available) to understand system architecture.
Trace dependencies—map out how different modules interact.
Talk to the original developers to understand historical decisions.
Identify key functionalities so you don’t accidentally break critical business logic.
Use tools like Dependency Graphs in Visual Studio to visualize dependencies.

📌 Example: If a class has a complex inheritance structure, refactoring it blindly may break polymorphism used elsewhere in the project.

2. Set Up Version Control (Git Is Your Best Friend)

📌 Why? You need a safety net. If refactoring breaks something, you must be able to roll back to a stable version.

🔹 Actions to Take:

Ensure all latest changes are committed and pushed to a remote repository (GitHub, Azure DevOps, Bitbucket, etc.).
Create a new branch specifically for refactoring instead of modifying the main branch.
Use descriptive commit messages when making changes so you can track what was done.
Leverage Git tags for marking stable versions.

📌 Example: If your refactoring accidentally removes an important feature, a simple git revert command can save hours of debugging.

3. Write or Expand Unit Tests

📌 Why? Tests act as a safety net. Without them, refactoring is like walking in a minefield—you won’t know you’ve broken something until users report issues.

🔹 Actions to Take:

Identify key areas of the code that lack tests and write unit tests before refactoring.
If possible, add integration tests to check how different modules interact.
Use mocking frameworks (like Moq in C#) to isolate dependencies during testing.
Run existing tests and ensure they pass before making any changes.

📌 Example: If you refactor a method that calculates invoice totals but forget an important tax calculation, tests will catch this before deployment.

4. Analyze Dependencies

📌 Why? Your code doesn’t exist in isolation—it interacts with third-party libraries, databases, APIs, and external services. Changes in one place can break functionality elsewhere.

🔹 Actions to Take:

Identify all third-party packages used in the project and check for deprecated dependencies.
Check for tight coupling between modules—overly dependent code makes refactoring risky.
List database dependencies to ensure changes don’t break queries.
Run static code analysis tools to detect potential side effects of refactoring.

📌 Example: If a refactored method relies on an old Entity Framework query, but the underlying database schema has changed, your application may crash at runtime.

5. Use Code Analysis Tools

📌 Why? Manually reviewing thousands of lines of code is inefficient. Static analysis tools can automatically detect issues, dead code, and inconsistencies before you even start refactoring.

🔹 Tools to Use:

SonarQube – Finds security vulnerabilities and code smells.
ReSharper – Suggests refactoring opportunities and optimizations.
.NET Code Analysis (built into Visual Studio) – Detects performance bottlenecks.
NDepend – Visualizes dependencies and suggests architectural improvements.

📌 Example: If your code contains unused variables, inefficient loops, or overly complex logic, ReSharper will flag these for cleanup automatically.

6. Refactor in Small Steps

📌 Why? Refactoring the entire codebase at once is a recipe for disaster. Breaking down the process into small, incremental improvements makes it easier to debug issues.

🔹 Best Practices:

Refactor one module at a time (e.g., start with controllers, then move to services).
Apply the Single Responsibility Principle—each class and method should do one thing well.
After each change, run tests to ensure nothing breaks.
Commit small changes frequently rather than waiting for a huge overhaul.

📌 Example: If you want to break down a 300-line method, first extract helper methods, then refactor loops, and finally apply better naming conventions.

7. Test Thoroughly After Each Change

📌 Why? Even the best refactoring efforts can introduce subtle bugs. Testing ensures that functionality remains intact after every change.

🔹 Types of Testing to Perform:
Unit Tests – Validate individual methods.
Integration Tests – Check how different modules interact.
Performance Tests – Ensure refactoring hasn’t introduced slowdowns.
UI Tests – If your code affects the frontend, test UI elements after backend changes.

📌 Example: If refactoring changes how customer discounts are calculated, run a test to ensure a 20% discount still applies correctly across all purchase scenarios.

Make Your Codebase a Joy to Work With!

Cleaning up your codebase is an ongoing process, but every small change makes a huge difference in the long run. Start by refactoring long methods, removing dead code, and optimizing your queries. Automate your cleanup process to ensure consistency across your project.

✨ Key Takeaways

Refactor long methods into smaller, testable functions.
Remove dead code before it clutters your project.
Use meaningful names – stop naming variables x and temp.
Optimize database queries – stop loading unnecessary data.
Automate code cleanup with linters and tools.

💡 Final Thought:

The cleaner your code, the easier it is to develop, test, and maintain. Invest in cleaning your code today to save time and frustration tomorrow and your future self (and teammates) will thank you.

Vinir Shah