netcdf-c

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Reported in https://github.com/Unidata/netcdf4-python/issues/999. Here's a simple C program that triggers the HDF Error. The rename only fails if the file is closed and then re-opened.

#include <netcdf.h>
#include <stdio.h>
#include <stdlib.h>
#define FILE_NAME "rename_test.nc"
#define DIM1_NAME "lon"
#define GRP1_NAME "grp"
#define VAR1_NAME "lon"
#define VAR2_NAME "longitude"
#define ERR(e) {printf("Error: %s\n", nc_strerror(e)); exit(2);}
int
main()
{
    int ncid, dimid, varid, ierr, grpid;
    /* Create a file with a variable in a group. */
    if ((ierr=nc_create(FILE_NAME, NC_NETCDF4, &ncid))) ERR(ierr);
    if ((ierr=nc_def_dim(ncid, DIM1_NAME, 1, &dimid))) ERR(ierr);
    if ((ierr=nc_def_grp(ncid, GRP1_NAME, &grpid))) ERR(ierr);
    if ((ierr=nc_def_var(grpid, VAR1_NAME, NC_FLOAT, 1, &dimid, &varid))) ERR(ierr);
    if ((ierr=nc_close(ncid))) ERR(ierr);
    /* Open the file and rename the variable. */
    if ((ierr=nc_open(FILE_NAME, NC_WRITE, &ncid))) ERR(ierr);
    if ((ierr=nc_inq_grp_ncid(ncid, GRP1_NAME, &grpid))) ERR(ierr);
    if ((ierr=nc_inq_varid(grpid, VAR1_NAME, &varid))) ERR(ierr);
    if ((ierr=nc_rename_var(grpid, varid, VAR2_NAME))) ERR(ierr);
    if ((ierr=nc_close(ncid))) ERR(ierr);
}

Well if you would just name the variable correctly in the first place, there would be no need for a rename! ;-)

However, I would have thought this simple example would have worked. Sigh.

It might be time for a total re-write of the renaming code, as outlined at the end of the long discussion on #597.

We observed the same issue in Netcdf version 4.8.1. Is there a targeted release to fix this issue?

Thanks, Nalini

I know it doesn't look like a particularly common issue... But would be nice to know if a fix is potentially planned for 4.8.2 or if it is on a back-burner for now.

It is definitely back-burner, because this requires a lot of work to fix.

But if you try renaming in different orders, some will work, and some won't.

Makes sense, thanks for the update!

Hi, just wanted to check if there are any new updates, or if this is still on a back-burner for now.