No default value defined for base URL in Create Term Definition

[kasei]

(Related to #265, #356)

Create Term Definition says that base URL is an optional input variable, but does not define a default value. It is then used unconditionally in step 21.3 and 21.4.

[gkellogg]

I'll check, but I believe that the only times that base URL would be used in Create Term Definition it is passed as an option.

[kasei]

Then I'd suggest adding language for a default value of null.

[gkellogg]

Updated in #377.

[kasei]

@gkellogg I don't see any change in #377 to the text about default values for the optional arguments in Create Term Definition. Am I missing something?

[gkellogg]

See the JsonLdOptions dictionary definition for initializers.

[kasei]

How is that relevant? This is about a named, optional argument to Create Term Definition, not about a field in a JsonLdOptions structure. Right?

[gkellogg]

Step 4 of expand() uses documentUrl, if it is available, otherwise the base option from options. As described for that parameter, default values (e.g., for base) are defined in JsonLdOptions.

It should be the case that when the API calls the Context Processing algorithm that the base IRI and original base URL options will always be set from one of these. There's code in the Context Processing algorithm to check if both context and base IRI aren't valid IRIs.

[kasei]

I'm lost. I still see Create Term Definition saying base URL is optional, and not providing a default value. And then using that value unconditionally. expand() is not the only place that Create Term Definition is invoked, so I don't think changes there can resolve this issue entirely.

For example, IRI Expansion 6.3 invokes Create Term Definition without a base URL argument. Now, it may be possible that this invocation cannot reach Create Term Definition 21.3, but that's not obvious to me, which is why I'm concerned about such use of an undefined value.

[gkellogg]

So, Create Term Definition is always called with the base URL argument. In Step 5 of expand() it is called with original base URL from active context established in step 4. In Step 6, it is called with the contextUrl from the header, which per HTTP will be an absolute URL.

In Step 4, original base URL is established either from the documentUrl of the remote document, or the base option, which is initialized to null in JsonLdOptions, if not set otherwise.

The Create Term Definition algorithm says that the default for base URL is false, but it should be null. I'll update that. But, those calls should probably use the base URL definition from the associated term in the context which is being passed.

[kasei]

So, Create Term Definition is always called with the base URL argument.

This is not true. Please see the example I just included above.

The optional inputs are base URL, protected which defaults to false, and override protected, defaulting to false, which is used to allow changes to protected terms..

I did not read this as providing a default value for base URL (since there are three arguments discussed, and two default values).

[gkellogg]

Yes, I misread that; it does now. It's also not necessary to pass a base URL from those places in Create Term Definition, as the default null value will suffice. (There could be a corner-case when expanding @type values when creating terms, if those @type values have embedded contexts, but those will be picked up when going back to the original term definition.)

[kasei]

d78d8d2 looks good. Thanks.