Invoking Examples.exe wordcount -p 2 -n 2 --local causes crash

[Emanuel Jöbstl]

Invoking Examples.exe wordcount -p 2 -n 2 --local with the latest commit (360ff09) causes an ArgumentOutOfRangeException.

The issue was already occurring in release_0.4.

Exception Details:

System.IndexOutOfRangeException was unhandled
  HResult=-2146233080
  Message=Index was outside the bounds of the array.
  Source=Microsoft.Research.Naiad
  StackTrace:
       at Microsoft.Research.Naiad.BaseController..ctor(Configuration config) in d:\Schuldateien\SS 14\Sources\naiad\Naiad\Runtime\Controlling\Controller.cs:line 771
       at Microsoft.Research.Naiad.NewController.FromConfig(Configuration conf) in d:\Schuldateien\SS 14\Sources\naiad\Naiad\Runtime\Controlling\Controller.cs:line 283
       at Microsoft.Research.Naiad.InternalOneOffComputation..ctor(Configuration configuration) in d:\Schuldateien\SS 14\Sources\naiad\Naiad\Runtime\SubgraphManager.cs:line 67
       at Microsoft.Research.Naiad.NewComputation.FromArgs(String[]& args) in d:\Schuldateien\SS 14\Sources\naiad\Naiad\Runtime\Controlling\Controller.cs:line 220
       at Microsoft.Research.Naiad.Examples.WordCount.WordCount.Execute(String[] args) in d:\Schuldateien\SS 14\Sources\naiad\Examples\Naiad\WordCount.cs:line 98
       at Microsoft.Research.Naiad.Examples.Program.Main(String[] args) in d:\Schuldateien\SS 14\Sources\naiad\Examples\Program.cs:line 105
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

[Frank McSherry]

Hi.

the -p argument indicates the intended process number (out of the number supplied to -n) this process will assume. So, with "-n 2", only values of "-p 0" and "-p 1" are valid. We should probably put better error reporting in there to explain what went wrong (which happens to be an out of bounds access on the list of hostnames, when the process tries to find which port it should be binding to).

If you had intended to set the number of threads, this is "-t 2" or whichever value you would like in there.