Hi! In version 0.15.6, it no longer seems possible to have

None

metadata in an asset, although it was possible in previous versions. This is the error:

dagster.core.errors.DagsterInvalidMetadata: Could not resolve the metadata value for "none_type" to a known type. Its type was <class 'NoneType'>. Consider wrapping the value with the appropriate MetadataValue type.

And the code to reproduce the error :

@asset(metadata={'none_type' : None})
def asset():
    return 1

job = define_asset_job('job', selection = AssetSelection.assets(asset))

@repository()
def repo():
    return [job, asset]

@sean - do you know what's going on here?

I have a fix out for this bug, thanks for this report!