c# - Is there any valid reason to ever ignore a caught exception

Question

Wow, I just got back a huge project in C# from outsourced developers and while going through my code review my analysis tool revealed bunches of what it considered bad stuff. One of the more discouraging messages was:

Exceptions.DontSwallowErrorsCatchingNonspecificExceptionsRule  : 2106 defects 

The developers assure me they had good reason for all the empty catch blocks, that sometimes the try with empty catch blocks are just there to ignore useless exceptions and keep the application from crashing. I feel this is a cop out and complete BS. Some of the examples I actually looked up were database calls where the record was being saved to the database, and in this case, if an exception was ignored, the user would get back an okay prompt, think everything was okay, and continue on with their work. In reality, their work was never saved. I think this is absolutely the most horrible kind of error. In this case, they are completely wrong in throwing that code in a try with an empty catch block. But my question is, "Is this EVER acceptable in ANY situation?" I think not, but I've been known to be wrong.

Answer 1

While there are some reasonable reasons for ignoring exceptions; however, generally it is only specific exceptions that you are able to safely ignore. As noted by Konrad Rudolph, you might have to catch and swallow an error as part of a framework; and as noted by osp70, there might be an exception generated by a framework that you know you can ignore.

In both of these cases though, you will likely know the exception type and if you know the type then you should have code similar to the following:

try {
  // Do something that might generate an exception
} catch (System.InvalidCastException ex) {
  // This exception is safe to ignore due to...
} catch (System.Exception ex) {
  // Exception handling
}

In the case of your application, is sounds like something similar might apply in some cases; but the example you give of a database save returning an "OK" even when there is an exception is not a very good sign.