Make creators attribute mandatory in JSON schema

[dmholtz]

In the JSON schema, the creators field of createrInfo was not listed as a required although the latest specification denotes the creator as mandatory (cp. 2.8.3 Cardinality, p. 19, SPEC).

[goneall]

I was assuming the "minItems" : 1 in the creators property provided the same validation of required.

After thinking about this, I am likely wrong in this assumption and will need to add any list with a minimum number of elements >=1 to the required list of properties.

@dmholtz let me know if agree my old assumption was wrong.

[dmholtz]

Thank you very much for the quick response!

In JSON schema, setting "minItems" : 1 has slightly different semantics: It means, that we must not provide an empty array for the creators field. However, omitting the creators property is perfectly fine with this schema. Example:

"creationInfo" : {
    "created" : "2010-01-29T18:30:22Z"
}

However, an empty creators array is not allowed:

"creationInfo" : {
    "created" : "2010-01-29T18:30:22Z"
    "creators": []
}

I think the idea of the specification is that a creator is always listed, and my PR should fix this. Nonetheless, we still need "minitems:" 1 to avoid empty lists.

[goneall]

@dmholtz Thanks for the detailed answer.

The JSON file is generated from the RDF OWL document. I'll fix the generator code to add the required parameter. This will probably result in a few more changes.

I'll probably just amend PR #659 to include this fix as well once it is regenerated.

Let's leave this PR open to track the issue until it is resolved in the other PR.

[dmholtz]

@goneall Thanks, I'll leave the PR open. Of course, combining both fixes is more efficient. From skimming the project, I didn't notice that schema has been generated :)

[kestewart]

Other has been merged. Closing.