This fixes and streamlines LIKE usage on the API, and makes wildcards (*) supported both on Solr and LEgacy search (with limits).
$query->filter = new Field('title', Operator::LIKE, "Ab*t");
Field types with support for LIKE (AFAIK based on trying to look at Integration Tests, Type- and Searchable-classes in kernel only) across both storage engines:
- Author (lowercase)
- Country (lowercase)
- ISBN (lowercase)
- MapLocation (address, as lowercase)
- RichText (within first 255 char of first paragraph)
- Textblock (lowercase, within first 255 char)
- Textline (lowercase)
This story also by means of cleanup adds missing (minimal) Field Criteria & SortingClause support for Author, RelationList (id) and RichText FieldTypes when using LegacySearchEngine.
SIDE / FYI 1: Several more field types support full Field criteria / sort clause on Solr only, but that has not changed in this story, this can be seen by looking for which once have a SearchField implements Indexable classes. Also those that have that also often indexes custom fields, like Selection's selected_option_value, which can be filtered on Field Criteria as exposed by CustomFieldInterface.
2: ImageAsset could be added also as a followup here to work like Relation (id).