Unreachable code in PIOc_read_darray()

[edhartnett]

In PIOc_read_daray() we have:

  /* Is a rearranger in use? */
   if (iodesc->rearranger > 0)
   {
       if (ios->ioproc && rlen > 0)
       {
           /* Get the MPI type size. */
           if ((mpierr = MPI_Type_size(iodesc->basetype, &tsize)))
               return check_mpi(file, mpierr, __FILE__, __LINE__);

           /* Allocate a buffer for one record. */
           if (!(iobuf = bget((size_t)tsize * rlen)))
               return pio_err(ios, file, PIO_ENOMEM, __FILE__, __LINE__);
       }
   }
   else
   {
       iobuf = array;
   }

There is another if statement later in the function as well.

I believe that iodesc->rearranger must be either 1 or 2, so it is never 0. Better to pioassert it and remove the unreachable code.

[jayeshkrishna]

I remember @jedwards4b mentioning in an issue before that the idea here was to explore cases where we don't use any rearrangers.

[edhartnett]

OK, cool. I will take it out for now.

For 2.2.0 a rearranger is required, and must be BOX or SUBSET.

Future versions of the code can do other things, but we will wait until we have a PR that implements a full feature, instead of leaving partial implementations in the code.