Add-ons Search Improvements 2.13.1

• Fix "array_fill_keys() expects parameter 1 to be array, null given" error when content weighting has not been configured

This feature is powering tag autocomplete and username autocomplete which supports partial matches, and non-prefix lookups on SpaceBattles.

• Require XenForo 2.2+, removes xf2.0/xf2.1 support
• Add "Specialized index" support
  • Specialized search index allows generating single-purpose elastic search indexes while re-using as much XF search infrastructure as possible.
    • Elasticsearch index is more akin to an SQL table than an entire database, so for very specific tasks a single purpose search index works better.
    • A separate index also allows changing indexing properties and re-indexing just that one index without impacting the main search index
  • Implementation of a specialized index notes;
    At the core, a XenForo search handler is used to drive the functionality.
    • The search handler should implement the interface \SV\SearchImprovements\Search\Specialized\SpecializedData
    • Use the types MetadataStructure::KEYWORD or MetadataStructure::STR fields in setupMetadataStructure.
      These types will be rewritten to add .exact & [/icode].ngram[/icode] subfields. To skip this pass ['skip-rewrite' => true] to the MetadataStructure::addField's 3rd argument.
      • MetadataStructure::KEYWORD - shortish text which is semi-structured such as tags or usernames
      • MetadataStructure::STR - Arbitrary text which uses phrases of text
    • Register the search handler with the following content type fields
      • specialized_search_handler_class
      • entity
    • This handler really shouldn't be registered with search_handler_class content type field.
    • Add the behavior SV\SearchImprovements:SpecializedIndexable to the entity.

Example of the 'indexes page'

• Fix the "Default search order" option would get reset when changing "Search options" under Enhanced Search Setup page