Sling ELT Error when using Sling's env.yaml to manage connections

[Westm7]

What's the issue?

I'm using sling's env.yaml file to manage my database connections, that way I can easily run the same sling commands outside of dagster when needed.

I just add a sling resource with no connections like below and everything worked well prior to version 1.8.12

sling_resource = {"sling": SlingResource(connections=[])}

Now I receive the following error when materializing my sling assets.

AttributeError: 'NoneType' object has no attribute 'get'
  File "venv/lib/python3.12/site-packages/dagster/_core/execution/plan/utils.py", line 54, in op_execution_error_boundary
    yield
  File "venv/lib/python3.12/site-packages/dagster/_utils/__init__.py", line 482, in iterate_with_context
    next_output = next(iterator)
                  ^^^^^^^^^^^^^^
  File "dagster_project/assets/sling_assets.py", line 41, in _assets
    yield from sling.replicate(context=context)
  File "venv/lib/python3.12/site-packages/dagster_embedded_elt/sling/sling_event_iterator.py", line 189, in __next__
    return next(self._inner_iterator)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "venv/lib/python3.12/site-packages/dagster_embedded_elt/sling/resources.py", line 407, in _replicate
    object_key = stream.get("config", {}).get("object")
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I've narrowed the error down to, "dagster_embedded_elt/sling/resources.py", line 407.
object_key = stream.get("config", {}).get("object")

The "config" key is set to None not null, so stream.get("config", {}) returns None instead of {} and the .get{"object") fails.

If you update line to 407 to:
object_key = (stream.get("config") or {}).get("object")
It works as expected.

What did you expect to happen?

Assets to be materialized without errors.

How to reproduce?

Reproduce by using sling's env.yaml to define your database connections and use a blank SlingResource() object with no connections in your dagster project.

sling_resource = {"sling": SlingResource(connections=[])}

and attempt to materialize an asset.

Dagster version

dagster, version 1.9.0

Deployment type

Local

Deployment details

No response

Additional information

If you update line to 407 of "dagster_embedded_elt/sling/resources.py" to:
object_key = (stream.get("config") or {}).get("object")
Assets materialize as expected.

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