Add support to dependencies

[Joxit]

I noticed that dependencies were often seen as countries, but it is not possible to use the boundary.country parameter to filter searches for documents that are located in dependencies.

Now the view boundary_country uses a multi_match query to match both country_a and dependency_a.

This code is fully backward compatible (needs API changes).

[missinglink]

I like this change.

The documentation says that the boudary.country filter accepts an ISO code, so despite the word 'country' being a misnomer I think this filter should support both country and dependency.

As such, the filter is just the opposite of pelias/api#1541

Allowing backwards compatibility is a nice touch, but I'm not too fussed, it should really consider both fields by default.

[Joxit]

Hum, ok so instead of retrieving fields using vars and configured in API package, I should add both fields here?

[missinglink]

Good question @orangejulius how do you think we are best to handle this?

[orangejulius]

Nice, this is great. Honestly, I think we can keep things simple and add the dependency field directly. Adding configuration is probably overkill.

[Joxit]

Hum, it seems like search and autocomplete are using a different fields.

Search uses parent.country_a
https://github.com/pelias/api/blob/cba5c681a35e2cabba3b503ed7907eea45d97746/query/search_defaults.js#L60-L65

While autocomplete uses parent.country_a.ngram
https://github.com/pelias/api/blob/cba5c681a35e2cabba3b503ed7907eea45d97746/query/autocomplete_defaults.js#L70-L75

I don't know if a use parent.country_a instead of parent.country_a.ngram for autocomplet, this will break something...
On the other hand, using ngram for 3 letters would be a bit too much ? 🤔

[missinglink]

hmm, so in general the autocomplete queries should use the ngram field, but in the case of the boundary.country filter it should only accept complete ISO 3166-2 or ISO 3166-3 codes, this behaviour should be the same between search and autocomplete.

[Joxit]

Excellent! I did the update 😉
The API PR is no longer needed \o/

[Joxit]

Hi there, I will close this PR given that pelias/api#1622 has already been merged and does the job now.