SharePoint's default for a text property is word breaking, so ours is too:
every keyword field gets the _words sibling unless it opts out with
NoWordBreaker, which now carries SharePoint's polarity as well. Artist,
album, camera model and the other facets match by word like name and title;
tags and favorites stay one label, ids, paths and the mime type one value.
KQL searches case-insensitively, so every keyword field gets its lowercased
search sibling unless it opts out: ids are opaque, paths are POSIX, the mime
type is normalized already. That takes the facets along, artist or camera
model match regardless of case, while the case-preserved base still answers
and aggregates. Which siblings a field carries is decided once, from the
struct and the overrides, and the renderers, the document writer and the
query lowering all read it from there.
A single word finds the names and titles that contain it, `report` finds
Report.txt, on bleve as well as on OpenSearch, which so far only did it by
accident of its dynamic mapping. Modelled like SharePoint's NoWordBreaker:
a keyword field is one whole value unless the override switches that off,
which adds a search-only _words sibling next to _lowercase, analyzed into
lowercased words (a dot is a word boundary, no stemming). The base stays the
whole value for returning and aggregating, wildcards and whole values keep
using _lowercase. Quotes do not change the meaning, a phrase is a phrase
either way, and there is no exact-match operator yet.
The guard only rejected CaseInsensitive when a non-keyword/path Type was set explicitly. With no Type, isCasedType treated the field as cased, so CaseInsensitive on an inferred numeric/bool/datetime field passed validation but produced no _lowercase sibling, and the query would silently match nothing. Validate now falls back to the inferred Go type.
CaseInsensitive routes queries to a <field>_lowercase sibling that is only generated for keyword/path fields, so marking any other type CaseInsensitive would silently match nothing. Validate now rejects it up front.
Build the bleve and OpenSearch index mappings from the Go struct via
reflection (json tags + per-field overrides) instead of hand-rolled
mappings and hit deserializers. New mapping package: BleveBuildMapping,
OpenSearchBuildMapping, Deserialize[T], PrepareForIndex; field decoding is
fail-soft. Mtime is typed as a date so mtime ranges are chronological on
both backends. Route CS3 facet parsing through mapping.DeserializeStringMap.
The any-valued (bleve hit) and string-valued (CS3 metadata) deserializers
share one generic fillStruct walker with a per-value setLeaf callback.
Dominik Schmidt