Suppressed Exception On The Empty Catch Block

When you investigate an issue or a problem you usually get the error or exception message first and then try to replicate that exception in a lower environment such as your local machine. What if there was an error but the application did not produced a message or even a trace where the error occurred? Big problem. One such case to avoid this problem and to avoid passing this problem to the next person that will support your application, is to avoid having suppressed exception on the empty catch block on your code. Yes, having an empty catch block will not be detected by the C# compiler, bummer.

The culprit

public class SilentExceptionSample
{

public void DivideOperation(int a, int b)
{
try
{
var result = a / b;
}
catch (Exception)
{
//throw;
}

}

}

The code above is a sample method that does not return anything (void) and an operation to divide a and b. A try catch block will be able to catch any exception that may happen but throwing the exception that may happen is a different scenario. Inside the catch block, the C# compiler allows the block to be empty and not return anything. Most of the time this block can contain a logic to handle the exception such as logging and external error handlers. What happens if the developer leaves the block empty without the intention of leaving it empty? Errors in your application will not have any trace.

Some unit testing

[TestFixture]
public class SuppressedExceptions
{

[Test]
public void Division_With_Exception_Test() {

var silentException = new SilentExceptionSample();

Assert.Throws(() => silentException.DivideOperation(1,0));
}

[Test]
public void Division_With_NoException_Test()
{
var silentException = new SilentExceptionSample();

Assert.DoesNotThrow(() => silentException.DivideOperation(1,1));
}

}

I created a unit test to test the exception, on this sample above its the DivideByZeroException, that the method will throw when you divide a number by zero. The test fails in the first scenario since the error suppressed exception on the empty catch block.

Test Results

Ways to avoid

There can be ways to avoid this code smell. I suggest the following…

Unit Test

– Perform unit tests on exception handling on your code.

Code Snippet

– Use the code snippets on Visual Studio. If you want to use a try catch block, typing in “try” then tab will auto complete the whole block.

Resharper

– Tools such as Resharper can help in detecting code smells. See the warning below from the Resharper engine on the empty catch block.
Resharper Warning

This type of code smell can be the source of problem you are investigating now or something you can prevent while in development. You’ve been warned! ­čÖé

Notepad++ – Source Code Editor and More

 

Using Notepad++ with Visual Studio

To compliment Visual Studio, I use Notepad++ as my other source code editor. Visual Studio is still my primary IDE but its good to have Notepad++ on the side for that quick search in files, syntax highlighting depending on the language or even when you want to compare texts or codes. There are other free code editors out there like Notepad2 or Sublime but my vote goes to Notepad++.

My Favorite Notepad++ Features

Syntax Highlighting

Notepad++ Syntax Highlighting

You get to choose from the programming languages like C#, C++, SQL, XML to Objective-C or Perl for syntax highlighting.

Find In Files

When I’m working on a big solution file in Visual Studio and I want to look for all references of a specific method, property or keyword I use Notepad++ Find In Files. Instead of waiting for Visual Studio to return to me a list of instances, I just search it with Notepad++. It will take time and it will make Notepad++ unresponsive during search but I can still continue with my coding in Visual Studio.

Notepad++ FindInFiles

 

Plugins

There are number of plugins that are available for install and download. The plugins manager is also a plugin by itself. Just like Package Manager in Visual Studio its the source where third party features can be found.

Notepad++ PluginsManager

 

Useful Plugins

TextFx

Notepad++ TextFxUnwrapText

If you find yourself working on a big chunk of text and its supposed to stay on one line, you can use the “Unwrap Text” option of TextFx. It will remove the newline and carriage return characters of the text to make it a one line.

StraightText

XML Tools

If you are working with XML messages that is sent as a one line of string you can use the “Pretty Print with Line Breaks” option of XML tools. This will arrange the XML nodes with proper indention to make it easier for you to inspect the XML string you have.

Notepad++ XMLToolsPrettyPrint

XMLFormattedText

 

I hope this little note for Notepad++ helps.