Merge pull request #2980 from cds-astro/fix-error-message-catalog-not-found

[vizier] raise a meaningful error message when no catalog is found in get_catalog_metadata

Author: bsipocz

CHANGES.rst

@@ -13,6 +13,12 @@ mpc
 
 - Parse star catalog information when querying observations database [#2957]
 
+vizier
+^^^^^^
+
+- Change the type of raised error when the catalog is not found in ``Vizier.get_catalog_metadata``
+  from ``IndexError`` to ``EmptyResponseError`` [#2980]
+
 
 Infrastructure, Utility and Other Changes and Additions
 -------------------------------------------------------

astroquery/utils/__init__.py

@@ -7,7 +7,7 @@
 from .class_or_instance import class_or_instance
 from .commons import (parse_coordinates, TableList, suppress_vo_warnings,
                       validate_email, ASTROPY_LT_4_3, ASTROPY_LT_5_0,
-                      ASTROPY_LT_5_1)
+                      ASTROPY_LT_5_1, ASTROPY_LT_6_0)
 from .process_asyncs import async_to_sync
 from .docstr_chompers import prepend_docstr_nosections
 from .cleanup_downloads import cleanup_saved_downloads
@@ -22,6 +22,7 @@
            'ASTROPY_LT_4_3',
            'ASTROPY_LT_5_0',
            'ASTROPY_LT_5_1',
+           'ASTROPY_LT_6_0',
            "async_to_sync",
            "prepend_docstr_nosections",
            "cleanup_saved_downloads"]

astroquery/utils/commons.py

@@ -31,12 +31,13 @@
            'validate_email',
            'ASTROPY_LT_4_3',
            'ASTROPY_LT_5_0',
-           'ASTROPY_LT_5_1']
+           'ASTROPY_LT_5_1',
+           'ASTROPY_LT_6_0']
 
 ASTROPY_LT_4_3 = not minversion('astropy', '4.3')
 ASTROPY_LT_5_0 = not minversion('astropy', '5.0')
-
 ASTROPY_LT_5_1 = not minversion('astropy', '5.1')
+ASTROPY_LT_6_0 = not minversion('astropy', '6.0')
 
 
 def parse_coordinates(coordinates):

astroquery/vizier/core.py

@@ -23,7 +23,7 @@
 from ..utils import async_to_sync
 from ..utils import schema
 from . import conf
-from ..exceptions import TableParseError
+from ..exceptions import TableParseError, EmptyResponseError
 
 
 __all__ = ['Vizier', 'VizierClass']
@@ -345,6 +345,9 @@ def get_catalog_metadata(self, *, catalog=None, get_query_payload=False):
         if get_query_payload:
             return metadata
         result = metadata.execute().to_table()
+        if len(result) == 0:
+            raise EmptyResponseError(f"'{catalog}' was not found in VizieR. Valid catalog names "
+                                     "often look like: 'IX/58', 'J/MNRAS/491/215', 'J/ApJS/256/33', etc.")
         # apply mask if the `alt_identifier` value is not a doi
         result["doi"].mask = True if "doi:" not in result["doi"][0] else False
         return result

astroquery/vizier/tests/test_vizier.py

@@ -3,11 +3,14 @@
 import requests
 from numpy import testing as npt
 import pytest
+from pyvo import registry
 from astropy.coordinates import SkyCoord
+import astropy.io.votable.tree as votree
 from astropy.table import Table
 import astropy.units as u
 
 from ... import vizier
+from ...exceptions import EmptyResponseError
 from ...utils import commons
 from astroquery.utils.mocks import MockResponse
 from .conftest import scalar_skycoord, vector_skycoord
@@ -271,3 +274,19 @@ def test_get_catalog_metadata(self):
         assert "WHERE ivoid = 'ivo://cds.vizier/test'" in request_dict["QUERY"]
         with pytest.raises(ValueError, match="No catalog name was provided"):
             vizier.core.Vizier().get_catalog_metadata()
+
+    def test_get_catalog_metadata_empty_result(self, monkeypatch):
+        """Checks that an empty result raises a meaningful error."""
+        v = vizier.core.Vizier(catalog="should_return_empty_result")
+
+        def return_empty_votable(_):
+            if commons.ASTROPY_LT_6_0:
+                table = votree.Table(votree.VOTableFile())
+            else:
+                table = votree.TableElement(votree.VOTableFile())
+            return table
+
+        monkeypatch.setattr(registry.regtap.RegistryQuery, "execute",
+                            return_empty_votable)
+        with pytest.raises(EmptyResponseError, match="'*' was not found in VizieR*"):
+            v.get_catalog_metadata()