additionalProperties=false is not set when using default Marshmallow schema options

[mwgamble]

The default value for the Marshmallow schema option unknown is RAISE. I expected this to result in additionalProperties: false being set on the generated schema. Unfortunately, this doesn't currently happen. Unless the unknown option is set explicitly, no additionalProperties keyword is added to the generated schema.

Is adding support for this feasible? I don't really want to have to manually add the necessary metadata to all my schemas.

[lafrech]

I guess you're right.

This could be fixed here:

apispec/src/apispec/ext/marshmallow/openapi.py

Lines 259 to 260 in 28a0f33

	if hasattr(Meta, "unknown") and Meta.unknown != marshmallow.EXCLUDE:
	jsonschema["additionalProperties"] = Meta.unknown == marshmallow.INCLUDE

Would you like to do the fix + tests and send a PR?

Thanks.

[mwgamble]

I don't have time to work on a PR at the moment sorry :(