Exception if Catalog doesn't have a description field during catalog.get_children()

[philvarner]

pystac version 0.5.6

This exception is thrown if a Catalog doesn't have a description field:

Error https://tamn.snapplanet.io/: <class 'KeyError'> 'description'
Traceback (most recent call last):
  File "/Users/philvarner/code/stac-api-validator/stac_api_validator/validate_all.py", line 22, in <module>
    (warnings, errors) = validate_api(root)
  File "/Users/philvarner/code/stac-api-validator/stac_api_validator/validations.py", line 124, in validate_api
    for collection in catalog.get_children():
  File "/Users/philvarner/.local/share/virtualenvs/stac-api-validation-suite-tzI1nfla/lib/python3.9/site-packages/pystac/stac_object.py", line 343, in get_stac_objects
    link.resolve_stac_object(root=self.get_root())
  File "/Users/philvarner/.local/share/virtualenvs/stac-api-validation-suite-tzI1nfla/lib/python3.9/site-packages/pystac/link.py", line 146, in resolve_stac_object
    obj = STAC_IO.read_stac_object(target_href, root=root)
  File "/Users/philvarner/.local/share/virtualenvs/stac-api-validation-suite-tzI1nfla/lib/python3.9/site-packages/pystac/stac_io.py", line 131, in read_stac_object
    return cls.stac_object_from_dict(d, href=uri, root=root)
  File "/Users/philvarner/.local/share/virtualenvs/stac-api-validation-suite-tzI1nfla/lib/python3.9/site-packages/pystac/serialization/__init__.py", line 37, in stac_object_from_dict
    return Catalog.from_dict(d, href=href, root=root)
  File "/Users/philvarner/.local/share/virtualenvs/stac-api-validation-suite-tzI1nfla/lib/python3.9/site-packages/pystac/catalog.py", line 791, in from_dict
    description = d.pop('description')
KeyError: 'description'

This was thrown from this code:

    catalog: Client = Client.open("https://tamn.snapplanet.io")
    for collection in catalog.get_children():
        collection.validate()

The "bad" catalog without a description is here: https://tamn.snapplanet.io/catalogs/concepts

[duckontheweb]

Thanks for reporting, this is fixed for PySTAC 1.0 by #451, but hasn't been implemented in other versions. We can look at applying that fix to the other release lines as well.

[philvarner]

I personally don't think it's necessary to apply it to other lines, as long as it's in 1.0

[duckontheweb]

@philvarner Sorry, I should be more specific about this...

It looks like this is failing on this link from the landing page:

{
  "rel": "child",
  "title": "Concepts",
  "type": "application/json",
  "href": "https://tamn.snapplanet.io/catalogs/concepts"
}

That href points to a "child" that looks like this:

{
  "id": "concepts",
  "title": "Concepts catalogs",
  "links": [
    {
      "rel": "self",
      "type": "application/json",
      "href": "https://tamn.snapplanet.io/catalogs/concepts"
    },
    {
      "rel": "root",
      "type": "application/json",
      "href": "https://tamn.snapplanet.io"
    }
  ],
  "stac_version": "1.0.0"
}

which is not a valid STAC object. As of PySTAC 1.0.0-rc.1 this will raise a STACTypeError in pystac.serialization.identify_stac_object instead of the cryptic KeyError.

[duckontheweb]

Actually, it looks like this gets incorrectly identified as a Catalog instead of raising a STACTypeError. I'll open a PR to fix this.