Poor method signatures
Published: 2023-03-05 22:59:48

Poorly designed method signatures are a prevalent code smell that can significantly impede code comprehension, maintenance, and testing. Method signatures serve as the public interface of your code, and it is crucial for them to clearly communicate the method's purpose, expected inputs, and returned outputs. Inadequate method signatures can lead to confusion and errors, particularly in team environments or when working with legacy code. Let's explore different categories of poor method signatures to be aware of:

Overloaded Methods:
Overloading methods with the same name but different parameter types or numbers can introduce confusion and errors. While overloading can be useful for offering multiple ways to perform an operation, excessive overloaded methods can make it challenging to remember the parameter order and types, leading to difficulties in distinguishing between them in code.
```csharp
// Methods that lead to confusion
public int Add(int a, int b)
public double Add(double a, double b)
public decimal Add(decimal a, decimal b)
```

Methods With Too Many Parameters:
Methods that require an excessive number of parameters can be challenging to understand and use. Having numerous parameters makes it difficult to remember their order and meaning, and it can also complicate testing the method with all possible parameter combinations. Moreover, methods with an abundance of parameters often indicate poor encapsulation, exposing too much internal state to callers.
```csharp
// Poor method signature
void Calculate(int x, int y, int z, bool isFast, bool isExact, bool useCache)

// Improved method signature
void Calculate(CalculationParameters parameters)
```

Methods With Inconsistent Parameter Ordering:
Inconsistent parameter ordering among methods in the same class or module can confuse developers, making it hard to remember the correct order for each method. Additionally, inconsistent parameter ordering can lead to mistakes when using code completion and copying and pasting code.
```csharp
// Poor parameter ordering
int Subtract(int b, int a)

// Improved parameter ordering
int Subtract(int a, int b)
```

Methods with Vague Return Types:
Methods with ambiguous return types can be challenging to understand and utilize. When a method returns a generic type like "object" or "dynamic," it becomes challenging to determine the actual return value and the available operations that can be performed on it. Such vague return types can hinder code completion and lead to errors when the returned value is used elsewhere in the code.

```csharp
// Vague return type
object ParseFileContents(File file)

// Clear return type
ParsedFileContents ParseFileContents(File file)
```

Methods with Too Many Side Effects:
Methods with excessive side effects are difficult to reason about and test. Modifying internal state or the state of other objects within a method can make it unclear what the method does and how it affects the rest of the code. Additionally, methods with numerous side effects can be challenging to test due to unexpected interactions with other parts of the code.
```csharp
// Code with to many side effects
void Deposit(double amount)
{
     // Add amount to balance
     // Code to update database and log transaction
}

// Omitted side effects
public void Deposit(double amount)
{
     // Add amount to balance
}
```

Poor Naming Convention:
Using inconsistent or unclear naming conventions for methods can hinder code readability and maintainability. Employing consistent naming conventions helps make code easier to understand and maintain, saving time and effort in the long run.
```csharp
// Poor naming convention
void save_to_database()

// Improved naming convention
void SaveToDatabase()
```

By following good practices for method signatures, you can make your code more readable, maintainable, and testable. Remember to choose clear and descriptive names, limit the number of parameters and side effects, use consistent parameter ordering and return types, and use refactoring tools like Rider to help you improve your code.

---

Here is a way of how Rider's refactoring tools can help to encapsulate a long parameter list of a method into a class:

- Select the method name.
- Right-click and select "Refactor" > "Convert" > "Transform Parameters" from the context menu.

Keyboard Shortcuts:
- Ctrl + Shift + R > Convert > Transform Parameters

Rider will then prompt you to enter a new name for the class(CalculationParameters), select which parameters to transform and will automatically update all references to that method replacing it with your new class.