Handle load_only marshmallow schema

[theirix]

A small fix that handles load_only schema parameter as well as dump_only. It allows to correctly handle schemas with Meta.load_only field.

[theirix]

Sorry, missed a test. It's an interesting question whether the dump_only field should appear when dump=False specified and load_only field for dump=True. Previously they appeared with a read_only=True swagger attribute and I doubt this is an expected behaviour.

[sloria]

@theirix I'm not sure about the failing test either. Intuitively, it does seem like load_only fields should be excluded if dump=True. Perhaps if the dump parameter isn't explicitly passed, both load_only and dump_only fields should appear. If dump=True is passed, load_only fields should not appear.

[theirix]

Yes, tri-state logic that you have described could help if we change signature for patched functions and a bunch of others to:

def schema2jsonschema(schema, spec=None, use_refs=True, dump=None, name=None):

And it is not a fully backward-compatible change. A patch can broke a library for those who uses load_only fields and expects these fields to be in result anyway. If apispec is used as a request/response serializer when dump parameter is explicitly specified or implied as a default parameter, a patch can be useful as it properly excludes load-only fields.

I don't insist in accepting this PR in a minor release. It's totally up to you to decide is it worth to change a behaviour in a such way.

[sloria]

Closing as this has gone stale, and I'm not sure this is an issue anymore. Feel free to re-open if it's still a valid issue.

[lafrech]

This is still an issue. It is discussed in #119.

There are three possible cases:

• Load only: parameter schema
• Dump only: response schema
• Load and dump: definition

A boolean dump parameter is not enough. We need either two parameters or a tri-state parameter.

[sloria]

OK, so it sounds like we'll need a different solution from this PR anyway.

[lafrech]

Exactly.