[Question] Is the property omitted, or is it nullable?

[gemmaro]

In JSONの形式 (Version 1.0), it is explained as follows.

"?"はない場合があるという意味です

Is the property omitted, or is it nullable? That is, Does the spec allow for both, or not, where property aaa is "?"?

{}

{ "aaa": null }

[na2hiro]

It means it's omitted like {}, which is similar to TypeScript's ?.

[gemmaro]

While fixing draft JSON Schema file (#51 ), following error occured to specification/files/ryuou201409020101.jkf.json (which is symlinked from test/files/jkf/ryuou201409020101.jkf for this constraint):

specification/files/ryuou201409020101.jkf.json invalid
[
  {
    instancePath: '/moves/44/move/from',
    schemaPath: '#/$defs/placeFormat/type',
    keyword: 'type',
    params: { type: 'object' },
    message: 'must be object'
  }
]

where

$ jq '.moves[44].move.from' specification/files/ryuou201409020101.jkf.json
null

According to your comment above, the existing JKF files (and possibly serializer, since it seems that they are generated automatically) is against the specification, I think.

[na2hiro]

Hmm, that's a good catch. I guess I didn't really pay attention to null vs undefined and wrote the jkf player.

So let me update the answer: I intended to be "lacking value", but null is acceptable if we consider the spec partially consists of jkf player too.

Options for the schema:

• Disallow null for the from field and make these files invalid
  • I want to avoid this to reject possibly generated JKF files for last several years
• Allow null along with missing value for from field (and other fields if we find ones), and note that it's a historical reason
• Allow null for all the fields annotated with ?

I'm not sure if which one of second of third is the best

[gemmaro]

In terms of JSON Schema, all options are possible 👍
Based on the current game record files, the third option seems to be a good choice. (Since the both notations has almost same semantics for humans.)

[na2hiro]

I see, makes sense. Let's go with the third option