From b8559ea841f6344f07b33cc669f6f070cf62cf79 Mon Sep 17 00:00:00 2001
From: marko-bekhta <marko.prykladna@gmail.com>
Date: Thu, 19 Sep 2024 09:45:26 +0200
Subject: [PATCH] HSEARCH-5245 Always add index.knn for OpenSearch indexes with
 vector fields

---
 .../AbstractElasticsearchVectorFieldTypeOptionsStep.java   | 4 +++-
 ...stractOpenSearch2VectorFieldTypeMappingContributor.java | 7 +++++--
 .../Elasticsearch812VectorFieldTypeMappingContributor.java | 6 ++++--
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/dsl/impl/AbstractElasticsearchVectorFieldTypeOptionsStep.java b/backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/dsl/impl/AbstractElasticsearchVectorFieldTypeOptionsStep.java
index 536a4ad7bf5..819ad23c0dc 100644
--- a/backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/dsl/impl/AbstractElasticsearchVectorFieldTypeOptionsStep.java
+++ b/backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/dsl/impl/AbstractElasticsearchVectorFieldTypeOptionsStep.java
@@ -106,7 +106,6 @@ public ElasticsearchIndexValueFieldType<F> toIndexFieldType() {
 		builder.codec( codec );
 		if ( resolvedSearchable ) {
 			builder.searchable( true );
-			mappingContributor.contribute( builder, this );
 			builder.queryElementFactory( PredicateTypeKeys.EXISTS, new ElasticsearchExistsPredicate.Factory<>() );
 		}
 
@@ -117,6 +116,9 @@ public ElasticsearchIndexValueFieldType<F> toIndexFieldType() {
 
 		builder.multivaluable( false );
 
+		// NOTE: we make additional contribution at the end of the configuration to make sure that
+		//  the context we pass (this) is fully configured:
+		mappingContributor.contribute( builder, this );
 		return builder.build();
 	}
 
diff --git a/backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/mapping/impl/AbstractOpenSearch2VectorFieldTypeMappingContributor.java b/backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/mapping/impl/AbstractOpenSearch2VectorFieldTypeMappingContributor.java
index 376e7e94c9b..1182d08e7db 100644
--- a/backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/mapping/impl/AbstractOpenSearch2VectorFieldTypeMappingContributor.java
+++ b/backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/mapping/impl/AbstractOpenSearch2VectorFieldTypeMappingContributor.java
@@ -64,9 +64,12 @@ public final <F> void contribute(ElasticsearchIndexValueFieldType.Builder<F> bui
 		SearchQueryElementFactory<? extends KnnPredicateBuilder,
 				ElasticsearchSearchIndexScope<?>,
 				ElasticsearchSearchIndexValueFieldContext<F>> factory = getKnnPredicateFactory( builder );
-		builder.queryElementFactory( PredicateTypeKeys.KNN, factory );
-
 		builder.contributeAdditionalIndexSettings( settings -> settings.addKnn( true ) );
+
+		// only add a predicate if the field on which this contribution happens is searchable:
+		if ( context.searchable() ) {
+			builder.queryElementFactory( PredicateTypeKeys.KNN, factory );
+		}
 	}
 
 	protected abstract <F> SearchQueryElementFactory<? extends KnnPredicateBuilder,
diff --git a/backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/mapping/impl/Elasticsearch812VectorFieldTypeMappingContributor.java b/backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/mapping/impl/Elasticsearch812VectorFieldTypeMappingContributor.java
index 6e743082399..a23a901179a 100644
--- a/backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/mapping/impl/Elasticsearch812VectorFieldTypeMappingContributor.java
+++ b/backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/types/mapping/impl/Elasticsearch812VectorFieldTypeMappingContributor.java
@@ -43,8 +43,10 @@ protected boolean indexOptionAddCondition(Context context) {
 
 	@Override
 	public <F> void contribute(ElasticsearchIndexValueFieldType.Builder<F> builder, Context context) {
-		builder.queryElementFactory( PredicateTypeKeys.KNN,
-				new ElasticsearchKnnPredicate.Elasticsearch812Factory<>( builder.codec() ) );
+		if (context.searchable() ) {
+			builder.queryElementFactory( PredicateTypeKeys.KNN,
+					new ElasticsearchKnnPredicate.Elasticsearch812Factory<>( builder.codec() ) );
+		}
 	}
 
 	private static String resolveDefault(VectorSimilarity vectorSimilarity) {