Ignore the bounding box ordering warning when reading files (#526)

Co-authored-by: Nadia Dencheva <nadia.dencheva@gmail.com>

CHANGES.rst

@@ -15,6 +15,9 @@
 
 - Force ``bounding_box`` to always be returned as a ``F`` ordered box. [#522] 
 
+- Add warning filter to asdf extension to prevent the ``bounding_box`` order warning for gwcs
+  objects originating from a file. [#526]
+
 0.21.0 (2024-03-10)
 -------------------
 

gwcs/converters/wcs.py

@@ -1,6 +1,8 @@
 # Licensed under a 3-clause BSD style license - see LICENSE.rst
 # -*- coding: utf-8 -*-
 
+import warnings
+from contextlib import suppress
 from asdf.extension import Converter
 
 
@@ -14,10 +16,17 @@ class WCSConverter(Converter):
     types = ["gwcs.wcs.WCS"]
 
     def from_yaml_tree(self, node, tag, ctx):
-        from ..wcs import WCS
+        from ..wcs import WCS, GwcsBoundingBoxWarning
         gwcsobj = WCS(node['steps'], name=node['name'])
         if 'pixel_shape' in node:
             gwcsobj.pixel_shape = node['pixel_shape']
+
+        # Ignore the warning about the bounding box order for data read from a
+        # file. This is causing issues with files from MAST.
+        with suppress(AttributeError), warnings.catch_warnings():
+            warnings.filterwarnings('ignore', category=GwcsBoundingBoxWarning)
+            _ = gwcsobj.bounding_box
+
         return gwcsobj
 
     def to_yaml_tree(self, gwcsobj, tag, ctx):

gwcs/examples.py

@@ -73,6 +73,17 @@ def gwcs_2d_shift_scale():
     pipe = [(DETECTOR_2D_FRAME, m3), (ICRC_SKY_FRAME, None)]
     return wcs.WCS(pipe)
 
+def gwcs_2d_bad_bounding_box_order():
+    m1 = models.Shift(1) & models.Shift(2)
+    m2 = models.Scale(5) & models.Scale(10)
+    m3 = m1 | m2
+
+    # Purposefully set the bounding box in the wrong order
+    m3.bounding_box = ((1, 2), (3, 4))
+
+    pipe = [(DETECTOR_2D_FRAME, m3), (ICRC_SKY_FRAME, None)]
+    return wcs.WCS(pipe)
+
 
 def gwcs_1d_freq_quantity():
 

gwcs/tests/test_wcs.py

@@ -25,6 +25,7 @@
 from ..utils import CoordinateFrameError
 from .utils import _gwcs_from_hst_fits_wcs
 from . import data
+from ..examples import gwcs_2d_bad_bounding_box_order
 
 
 data_path = os.path.split(os.path.abspath(data.__file__))[0]
@@ -1443,3 +1444,29 @@ def test_bounding_box_is_returned_F():
 
     # Show the the bounding box is different between the two WCS objects
     assert gwcs_object_after.bounding_box != gwcs_object_before.bounding_box
+
+
+def test_no_bounding_box_if_read_from_file(tmp_path):
+    bad_wcs = gwcs_2d_bad_bounding_box_order()
+
+    # Check the waring is issued for the bounding box of this WCS object
+    with pytest.warns(wcs.GwcsBoundingBoxWarning):
+        bad_wcs.bounding_box
+
+    # Check that the warning is not issued again the second time
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        bad_wcs.bounding_box
+
+    # Write a bad wcs bounding box to an asdf file
+    asdf_file = tmp_path / "bad_wcs.asdf"
+    af = asdf.AsdfFile({"wcs": gwcs_2d_bad_bounding_box_order()}) # re-create the bad wcs object
+    af.write_to(asdf_file)
+
+    with asdf.open(asdf_file) as af:
+        wcs_from_file = af["wcs"]
+
+    # Check that no warning is issued for the bounding box of this WCS object
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        wcs_from_file.bounding_box