Bubble up exception in validators.resolve_from_url

[podosinovik]

So that I don't bury the (causal but not related) lead, the geojson.org schemas are unreachable (e.g. https://geojson.org/schema/Feature.json).

I discovered this when validating a pystac Item (pystac 1.1.0). The exception that I correctly saw was:

File ".../python3.9/site-packages/jsonschema/validators.py", line 779, in resolve_from_url
    raise exceptions.RefResolutionError(exc)
jsonschema.exceptions.RefResolutionError: HTTP Error 404: Not Found

However, the specific URL is nowhere to be found in the exception. It would be really useful to have this information bubbled up in exc so that the developer doesn't have to go digging through the debug stack.

Thanks!

[podosinovik]

The schema issue has already been captured in the geojson repo: geojson/schema#29

[gadomski]

If requests is present on the system, jsonschema doesn't propagate the problematic URL. I've opened python-jsonschema/jsonschema#1050 to fix, and consider that a blocker to fixing this issue. I've got a WIP branch that has some test infrastructure we can use once/if jsonschema is updated: https://github.com/stac-utils/pystac/tree/issues/622-better-exceptions.

I'm moving this back to the 1.8 milestone since I don't know how long it'll be before we'll get an upstream fix.

[gadomski]

Well, looks like jsonschema is going through a major overhaul: python-jsonschema/jsonschema#1050 (comment). All the more reason to hold off on any changes/fixes until that lands.