Test dynamic behavior of "$recursiveRef" and "$recursiveAnchor"

[handrews]

Test where "$recursiveRef" targets a "$recursiveAnchor": true schema and there is also an outer scope "$recursiveAnchor": true to which the $recursiveRef should actually resolve.

Should probably have at least two cases:

• the outer scope is the entry point (as with our multi-vocabulary meta-schemas that include the applicator vocabulary)
• the outer scope is intermediate (such as when using links.json, the schema for hyper-schema's Link Description Object, as the entry point).

[karenetheridge]

I don't know if we want to do this for draft2019-09, given that the semantics of these keywords are changing soon, but we should also test what happens with this schema:

{
  "$id": "http://localhost:1234",
  "type": "object",
  "properties": {
    "myprop": {
      "$recursiveAnchor": true,
      "anyOf": [
        { "type": "string" },
        {
          "type": "object",
          "additionalProperties": { "$recursiveRef": "#" },
        }
      ]
    }
  }
}

..and also the more interesting case where $recursiveRef is not "#", but the fragment is not empty (either a json pointer or a plain-name fragment serves equally well for this case) -- the fragment has to be resolved against the uri marking the position of the $recursiveAnchor, but there is no $id there, so how do we perform resolution? I suspect that with the way the spec is written now, this can only blow up, since we have no provision for "resolve one fragment against the other by concatenating them together" or anything like that.

(@handrews I haven't read the new keyword proposals in great detail yet so I don't know if this case has been considered yet.. I just mention it without prejudice in the sense that this sort of scenario should be covered too.)

[handrews]

@karenetheridge in the example schema you give, I believe the $recursiveRef functions just as $ref, because there is no $recursiveAnchor located at the initial target (the root schema). The presence of $recursiveAnchor anywhere else is irrelevant.

Regarding fragments, this is one reason why $recursiveRef MUST target a resource root schema. In URI reference resolutions, fragments are replaced, never combined.

[karenetheridge]

Regarding fragments, this is one reason why $recursiveRef MUST target a resource root schema.

Sorry for being obtuse, but there's a few weird edge cases here and I want to completely understand. Does this mean that the final target for a $recursiveRef must be a resource root schema (which I believe means there MUST always be an $id keyword at the same location)? Or that the intermediary target (i.e. the location of the outermost $recursiveAnchor) must be a resource root schema?

For example, is this legal?

{
  "$id": "foo.json",
  "$recursiveAnchor": true,
  "$defs": {
    "my_def" : { ... },
  },
 ...

  ..and somewhere else in the schema:
  { "$recursiveRef": "#/defs/my_def", ... }
}

This would mean that the $recursiveRef is always targeting a definition with a specific name within the referenced resource, but that referenced resource could change depending on which $recursiveAnchor is in effect at the source of the $recursiveRef.

At the moment, I am throwing an exception on the combination of: $recursiveRef has a non-empty fragment, AND the canonical uri of the active $recursiveAnchor has a fragment (which would be any subschema that lacks an $id).

I tried for a little bit to concoct a test case with $recursiveRef having a non-empty path in the URI, and had to lie down from dizziness. :/

[handrews]

Does this mean that the final target for a $recursiveRef must be a resource root schema (which I believe means there MUST always be an $id keyword at the same location)? Or that the intermediary target (i.e. the location of the outermost $recursiveAnchor) must be a resource root schema?

both.

[handrews]

AND the canonical uri of the active $recursiveAnchor has a fragment (which would include things with an $anchor).

The presence of $anchor alongside $recursiveAnchor is irrelevant. # is a JSON Pointer fragment. Of course this all changes in the next draft, and I'm hoping that since OAS 3.1 will be on the next draft, people will deprecate 2019-09 and not use it in production at all.

[karenetheridge]

I guess I'll not worry too much about $recursiveAnchor and $recursiveRef in 2019-09 then :) I got the multi-step resolution working, although I had difficulty coming up with some good tests that went beyond just using "#" in $recursiveRef.

[epoberezkin]

Hi all. Am I right that there will be no tests for recursiveRef? And that it will be dynamicRef? Is there any timeline when it would stabilize?

[jdesrosiers]

@karenetheridge wrote some tests for $recursiveRef/$recursiveAnchor #391. I'm not sure why progress on that PR stalled out, but it would be great to see that finished and merged.

$recrusiveRef/$recursiveAnchor is set in stone in draft 2019-09. It's not going to change other than that they will be replaced with $dynamicRef/$dynamicAnchor in the next draft. At this point there's no reason to expect any additional changes to $dynamicRef/$dynamicAnchor before the next draft is published.

[epoberezkin]

I haven't read the next one yet - is it just renaming them? Or do they also extend "recursive" in some way?

[jdesrosiers]

It's more than a rename. $dynamicAnchor is a string ({ "$dynamicRef": "foo" }) instead of a boolean ({ "$recursiveRef": true }) and is allowed anywhere in the schema instead of only at the top level. $dynamicRef works pretty much the same way as $recursiveRef except that it can reference a specific $dynamicAnchor ({ "$dynamicRef": "#foo" }) rather than only a top level schema ({ "$recursiveRef": "#" }).

This change makes it so $refing an $anchor works exactly like $dynamicRefing a $dynamicAnchor except for the dynamic resolution part.

[handrews]

It looks like this is now tested quite thoroughly. @Julian @karenetheridge any reason not to go ahead and close this?

[Julian]

Yup, indeed. Closing, thanks folks.