PostSharp stackoverflow on aspect

Question

Aspect class looks like this:

  using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using System.Threading.Tasks;
  using System.Diagnostics;
  using PostSharp.Aspects;

  namespace GlobalExceptionHandler
  {

[Serializable]
class MyDebugger : OnMethodBoundaryAspect
{
    public override void OnEntry(MethodExecutionArgs args)
    {
        Console.WriteLine("METHOD ENTRY: " + args.Method.Name + "(" + args.Arguments.GetArgument(0) + ")");
    }
    public override void OnException(MethodExecutionArgs args)
    {
        Console.WriteLine("Exception at: " + args.Method.Name + "()");
        args.FlowBehavior = FlowBehavior.Continue;
    }
}

}

I am applying the aspect to mscorlib assembly to system namespace but excluding the console class which i thought was causing the stackoverflow on my aspect as it uses a Console.WriteLine to print the log.

[assembly: GlobalExceptionHandler.MyDebugger(AttributeTargetAssemblies = "mscorlib", AttributeTargetTypes = "System.Console", AttributeExclude = true, AttributePriority = 100000)]

[assembly: GlobalExceptionHandler.MyDebugger(AttributeTargetAssemblies = "mscorlib", AttributeTargetTypes = "System.*")]

And im still getting the stackoverflow exception

Answer 1

The expression in the aspect code where you add several strings using "+" is actually emitted as a call to String.Concat method by C# compiler. So you get this code in the OnEntry:

Console.WriteLine(String.Concat("METHOD ENTRY: ", args.Method.Name, "(", args.Arguments.GetArgument(0), ")"));

To avoid recursion you can exclude System.String class in the same way you did with System.Console. However, in general case it's better to add a thread-static flag to your aspect that will serve to stop recursive calls.

[Serializable]
class MyDebugger : OnMethodBoundaryAspect
{
    [ThreadStatic]
    private static bool isLogging;

    public override void OnEntry( MethodExecutionArgs args )
    {
        if ( isLogging ) return;

        isLogging = true;
        Console.WriteLine( "METHOD ENTRY: " + args.Method.Name + "(" + args.Arguments.GetArgument( 0 ) + ")" );
        isLogging = false;
    }

    public override void OnException( MethodExecutionArgs args )
    {
        if ( isLogging ) return;

        isLogging = true;
        Console.WriteLine( "Exception at: " + args.Method.Name + "()" );
        args.FlowBehavior = FlowBehavior.Continue;
        isLogging = false;
    }
}