Caught exception is null itself !

Question

I have an ASP.NET applications. Everything was fine, but recently I get exceptions that are null themselves:

try {     // do something } catch (Exception ex) {     Logger.Log("Error while tried to do something. Error: " + ex.Message); } 

Sometimes ex is null itself !

Any idea?

Answer 1

For anyone ending up here, I've found an instance where this is possible (If only detectable in the debugger). VS2013 Update 4.

Broken:

try {     // do something } catch (WebException ex) // <- both variables are named 'ex' {     Logger.Log("Error while tried to do something. Error: " + ex.Message); } catch (Exception ex) // <- this 'ex' is null {     Logger.Log("Error while tried to do something. Error: " + ex.Message); } 

The solution is to name your exception variables differently.

Fixed:

try {     // do something } catch (WebException webEx) // <- all good in the hood {     Logger.Log("Error while tried to do something. Error: " + webEx.Message); // <- } catch (Exception ex) // <- this 'ex' correctly contains the exception {     Logger.Log("Error while tried to do something. Error: " + ex.Message); } 

Answer 2

In my case, the cause was a StackOverflowException. Such exceptions normally don't reach the catch block at all, but this time, for some reason I don't understand, it did reach the catch block, but the exception was null.