Support FITS files with distortion maps when given as file name

Author: svank

reproject/tests/data/image_with_distortion_map.fits

@@ -2,6 +2,7 @@
 import numpy as np
 import pytest
 from astropy.io import fits
+from astropy.utils.data import get_pkg_data_filename
 from astropy.wcs import WCS
 
 from reproject.conftest import set_wcs_array_shape
@@ -41,6 +42,12 @@ def test_parse_input_data_missing_hdu_in():
         parse_input_data(hdulist)
 
 
+def test_parse_input_data_distortion_map():
+    # Verify that the file can be successfully loaded and parsed
+    fname = get_pkg_data_filename("data/image_with_distortion_map.fits", package="reproject.tests")
+    parse_input_data(fname, hdu_in=0)
+
+
 @pytest.mark.filterwarnings("ignore:unclosed file:ResourceWarning")
 def test_parse_input_shape(tmpdir, valid_celestial_input_shapes):
     """

reproject/tests/test_utils.py

@@ -92,7 +92,7 @@ def hdu_to_numpy_memmap(hdu):
     )
 
 
-def parse_input_data(input_data, hdu_in=None):
+def parse_input_data(input_data, hdu_in=None, source_hdul=None):
     """
     Parse input data to return a Numpy array and WCS object.
     """
@@ -109,9 +109,9 @@ def parse_input_data(input_data, hdu_in=None):
                 )
             else:
                 hdu_in = 0
-        return parse_input_data(input_data[hdu_in])
+        return parse_input_data(input_data[hdu_in], source_hdul=input_data)
     elif isinstance(input_data, PrimaryHDU | ImageHDU | CompImageHDU):
-        return hdu_to_numpy_memmap(input_data), WCS(input_data.header)
+        return (hdu_to_numpy_memmap(input_data), WCS(input_data.header, fobj=source_hdul))
     elif isinstance(input_data, tuple) and isinstance(input_data[0], np.ndarray | da.core.Array):
         if isinstance(input_data[1], Header):
             return input_data[0], WCS(input_data[1])