[bug #64420] Error message of wrongly specified HDU doesn't give the problematic option name

[Mohammad Akhlaghi]

URL:
  <https://savannah.gnu.org/bugs/?64420>

                 Summary: Error message of wrongly specified HDU doesn't give
the problematic option name
                   Group: GNU Astronomy Utilities
               Submitter: makhlaghi
               Submitted: Wed 12 Jul 2023 07:44:30 PM BST
                Category: All Gnuastro
                Severity: 3 - Normal
              Item Group: Output not reasonable
                  Status: In Progress
                 Privacy: Public
             Assigned to: makhlaghi
             Open/Closed: Open
         Discussion Lock: Any


    _______________________________________________________

Follow-up Comments:


-------------------------------------------------------
Date: Wed 12 Jul 2023 07:44:30 PM BST By: Mohammad Akhlaghi <makhlaghi>
When the wrongly given HDU to a program is not for the '--hdu' option, the
error message only talks about '--hdu'! 

For example see the command below and assume that the desired HDU in
'grid.fits' is the 0th HDU.


$ astwarp input.fits --gridfile=grid.fits
"astwarp: grid.fits: only has one HDU.

You should tell Gnuastro's command-line programs to look for data in the
primary HDU with the '--hdu=0' option (or '-h0'). For library users, you
can put "0" (a string literal) for the function's HDU argument. For more,
see the FOOTNOTE below.

...


>From the error message, the user will infer that they should add '--hdu=0' (or
'-h0'); but that will not solve the problem! In fact, since '--hdu=0' tells
Warp to look into the 0th HDU of 'input.fits', it will probably crash because
the 0-th HDU usually doesn't have any data! 

As a result, the situation becomes very confusing and frustrating.

In the example above, the error message should suggest using '--gridhdu=0'.

This issue was reported by Aaron Watkins.







    _______________________________________________________

Reply to this item at:

  <https://savannah.gnu.org/bugs/?64420>

_______________________________________________
Message sent via Savannah
https://savannah.gnu.org/