Snapshots of integer pbuf fields are incorrect

[jimmielin]

What happened?

Snapshot writing of integer type (dtype_i4) pbuf fields are incorrect.

cam_snapshot_common.F90::cam_pbuf_snapshot_all_outfld reads all pbuf fields into a real(r8) array but if the data is in dtype_i4 the data read into the arrays will not be correct:

subroutine cam_pbuf_snapshot_all_outfld(lchnk, file_num, pbuf)
   use physics_buffer, only: pbuf_is_used

   integer,                   intent(in) :: lchnk
   integer,                            intent(in) :: file_num
   type(physics_buffer_desc), pointer, intent(in) :: pbuf(:)

   integer :: i, pbuf_idx, ndims
   real(r8), pointer, dimension(:,:)           :: tmpptr2d
   real(r8), pointer, dimension(:,:,:)         :: tmpptr3d
   real(r8), pointer, dimension(:,:,:,:)       :: tmpptr4d
   real(r8), pointer, dimension(:,:,:,:,:)     :: tmpptr5d


   do i=1, npbuf_var

      pbuf_idx= pbuf_get_index(pbuf_snapshot(i)%ddt_string)

...
         ! Retrieve the pbuf data (dependent on the number of dimensions)
         ndims = count(pbuf_snapshot(i)%dim_name(:) /= '')

         select case (ndims)  ! Note that dimension 5 and 6 do not work with pbuf_get_field, so these are not used here

         case (1)
            call pbuf_get_field(pbuf, pbuf_idx, tmpptr2d)
            call outfld(pbuf_snapshot(i)%standard_name, tmpptr2d, pcols, lchnk)
...

What are the steps to reproduce the bug?

Observe saved snapshot files for pbuf fields that have dtype_i4, e.g.

   ! wg top level index of deep cumulus convection.
   call pbuf_add_field('ZM_JT', 'physpkg', dtype_i4, (/pcols/), zm_jt_idx)

   ! wg gathered values of maxi.
   call pbuf_add_field('ZM_MAXG', 'physpkg', dtype_i4, (/pcols/), zm_maxg_idx)

   ! map gathered points to chunk index
   call pbuf_add_field('ZM_IDEEP', 'physpkg', dtype_i4, (/pcols/), zm_ideep_idx)

instead of actual values, the data is written incorrectly:

 pbuf_ZM_JT =
  4.03179200377274e-313, 4.24399158286927e-313, 4.03179200382215e-313,
    4.03179200377274e-313, 4.88059032015885e-313, 4.88059032035648e-313,
    4.88059032035648e-313, 3.81959242487384e-313, 4.45619116191639e-313,

What CAM tag were you using?

cam6_4_047

What machine were you running CAM on?

CISL machine (e.g. cheyenne)

What compiler were you using?

Intel

Path to a case directory, if applicable

No response

Will you be addressing this bug yourself?

Any CAM SE can do this

Extra info

No response