HSEARCH-4827 Don't allow some projections within a nested context

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/logging/impl/Log.java

@@ -803,4 +803,8 @@ SearchException cannotHighlightInNestedContext(String currentNestingField,
 	@Message(id = ID_OFFSET + 171,
 			value = "The highlight projection cannot be applied to a field from an object using `ObjectStructure.NESTED` structure.")
 	SearchException cannotHighlightFieldFromNestedObjectStructure(@Param EventContext eventContext);
+
+	@Message(id = ID_OFFSET + 172, value = "'%1$s' cannot be nested in an object projection. "
+			+ "%2$s")
+	SearchException cannotUseProjectionInNestedContext(String projection, String hint, @Param EventContext eventContext);
 }

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/reporting/impl/ElasticsearchSearchHints.java

@@ -0,0 +1,26 @@
+/*
+ * Hibernate Search, full-text search for your domain model
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.search.backend.elasticsearch.reporting.impl;
+
+import org.hibernate.search.engine.backend.reporting.spi.BackendSearchHints;
+import org.hibernate.search.util.common.logging.impl.MessageConstants;
+
+import org.jboss.logging.Messages;
+import org.jboss.logging.annotations.Message;
+import org.jboss.logging.annotations.MessageBundle;
+
+@MessageBundle(projectCode = MessageConstants.PROJECT_CODE)
+public interface ElasticsearchSearchHints extends BackendSearchHints {
+
+	ElasticsearchSearchHints INSTANCE = Messages.getBundle( ElasticsearchSearchHints.class );
+
+	@Message(value = "A JSON hit projection represents a root hit object and adding it as a part of the nested object projection might produce misleading results.")
+	String jsonHitProjectionNestingNotSupportedHint();
+
+	@Message(value = "A source projection represents a root source object and adding it as a part of the nested object projection might produce misleading results.")
+	String sourceProjectionNestingNotSupportedHint();
+}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchDocumentReferenceProjection.java

@@ -6,10 +6,12 @@
  */
 package org.hibernate.search.backend.elasticsearch.search.projection.impl;
 
+import org.hibernate.search.backend.elasticsearch.reporting.impl.ElasticsearchSearchHints;
 import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexScope;
 import org.hibernate.search.engine.backend.common.DocumentReference;
 import org.hibernate.search.engine.search.loading.spi.LoadingResult;
 import org.hibernate.search.engine.search.loading.spi.ProjectionHitMapper;
+import org.hibernate.search.engine.search.projection.spi.ProjectionTypeKeys;
 
 import com.google.gson.JsonObject;
 
@@ -32,6 +34,10 @@ public String toString() {
 
 	@Override
 	public Extractor<?, DocumentReference> request(JsonObject requestBody, ProjectionRequestContext context) {
+		context.checkNotNested(
+				ProjectionTypeKeys.DOCUMENT_REFERENCE,
+				ElasticsearchSearchHints.INSTANCE.documentReferenceProjectionNestingNotSupportedHint()
+		);
 		helper.request( requestBody, context );
 		return this;
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchEntityCompositeProjection.java

@@ -0,0 +1,32 @@
+/*
+ * Hibernate Search, full-text search for your domain model
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.search.backend.elasticsearch.search.projection.impl;
+
+import org.hibernate.search.backend.elasticsearch.reporting.impl.ElasticsearchSearchHints;
+import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexScope;
+import org.hibernate.search.engine.search.projection.spi.ProjectionTypeKeys;
+
+import com.google.gson.JsonObject;
+
+public class ElasticsearchEntityCompositeProjection<E> extends AbstractElasticsearchProjection<E> {
+	private final ElasticsearchSearchProjection<E> delegate;
+
+	public ElasticsearchEntityCompositeProjection(ElasticsearchSearchIndexScope<?> scope,
+			ElasticsearchSearchProjection<E> delegate) {
+		super( scope );
+		this.delegate = delegate;
+	}
+
+	@Override
+	public Extractor<?, E> request(JsonObject requestBody, ProjectionRequestContext context) {
+		context.checkNotNested(
+				ProjectionTypeKeys.ENTITY,
+				ElasticsearchSearchHints.INSTANCE.entityProjectionNestingNotSupportedHint()
+		);
+		return delegate.request( requestBody, context );
+	}
+}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchEntityLoadingProjection.java

@@ -6,9 +6,11 @@
  */
 package org.hibernate.search.backend.elasticsearch.search.projection.impl;
 
+import org.hibernate.search.backend.elasticsearch.reporting.impl.ElasticsearchSearchHints;
 import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexScope;
 import org.hibernate.search.engine.search.loading.spi.LoadingResult;
 import org.hibernate.search.engine.search.loading.spi.ProjectionHitMapper;
+import org.hibernate.search.engine.search.projection.spi.ProjectionTypeKeys;
 
 import com.google.gson.JsonObject;
 
@@ -30,6 +32,10 @@ public String toString() {
 
 	@Override
 	public Extractor<?, E> request(JsonObject requestBody, ProjectionRequestContext context) {
+		context.checkNotNested(
+				ProjectionTypeKeys.ENTITY,
+				ElasticsearchSearchHints.INSTANCE.entityProjectionNestingNotSupportedHint()
+		);
 		helper.request( requestBody, context );
 		return this;
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchEntityReferenceProjection.java

@@ -6,10 +6,12 @@
  */
 package org.hibernate.search.backend.elasticsearch.search.projection.impl;
 
+import org.hibernate.search.backend.elasticsearch.reporting.impl.ElasticsearchSearchHints;
 import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexScope;
 import org.hibernate.search.engine.backend.common.DocumentReference;
 import org.hibernate.search.engine.search.loading.spi.LoadingResult;
 import org.hibernate.search.engine.search.loading.spi.ProjectionHitMapper;
+import org.hibernate.search.engine.search.projection.spi.ProjectionTypeKeys;
 
 import com.google.gson.JsonObject;
 
@@ -30,6 +32,10 @@ public String toString() {
 
 	@Override
 	public Extractor<?, R> request(JsonObject requestBody, ProjectionRequestContext context) {
+		context.checkNotNested(
+				ProjectionTypeKeys.ENTITY_REFERENCE,
+				ElasticsearchSearchHints.INSTANCE.entityReferenceProjectionNestingNotSupportedHint()
+		);
 		helper.request( requestBody, context );
 		return this;
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchExplanationProjection.java

@@ -8,6 +8,7 @@
 
 import org.hibernate.search.backend.elasticsearch.gson.impl.JsonAccessor;
 import org.hibernate.search.backend.elasticsearch.gson.impl.JsonObjectAccessor;
+import org.hibernate.search.backend.elasticsearch.reporting.impl.ElasticsearchSearchHints;
 import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexScope;
 import org.hibernate.search.engine.search.loading.spi.LoadingResult;
 import org.hibernate.search.engine.search.loading.spi.ProjectionHitMapper;
@@ -31,6 +32,10 @@ public String toString() {
 
 	@Override
 	public Extractor<?, JsonObject> request(JsonObject requestBody, ProjectionRequestContext context) {
+		context.checkNotNested(
+				ElasticsearchProjectionTypeKeys.EXPLANATION,
+				ElasticsearchSearchHints.INSTANCE.explanationProjectionNestingNotSupportedHint()
+		);
 		REQUEST_EXPLAIN_ACCESSOR.set( requestBody, true );
 		return this;
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchIdProjection.java

@@ -6,10 +6,12 @@
  */
 package org.hibernate.search.backend.elasticsearch.search.projection.impl;
 
+import org.hibernate.search.backend.elasticsearch.reporting.impl.ElasticsearchSearchHints;
 import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexScope;
 import org.hibernate.search.engine.backend.types.converter.spi.ProjectionConverter;
 import org.hibernate.search.engine.search.loading.spi.LoadingResult;
 import org.hibernate.search.engine.search.loading.spi.ProjectionHitMapper;
+import org.hibernate.search.engine.search.projection.spi.ProjectionTypeKeys;
 
 import com.google.gson.JsonObject;
 
@@ -33,7 +35,11 @@ public String toString() {
 	}
 
 	@Override
-	public Extractor<String, I> request(JsonObject requestBody, ProjectionRequestContext context) {
+	public Extractor<?, I> request(JsonObject requestBody, ProjectionRequestContext context) {
+		context.checkNotNested(
+				ProjectionTypeKeys.ID,
+				ElasticsearchSearchHints.INSTANCE.idProjectionNestingNotSupportedHint()
+		);
 		extractionHelper.request( requestBody, context );
 		return this;
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchJsonHitProjection.java

@@ -6,6 +6,7 @@
  */
 package org.hibernate.search.backend.elasticsearch.search.projection.impl;
 
+import org.hibernate.search.backend.elasticsearch.reporting.impl.ElasticsearchSearchHints;
 import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexScope;
 import org.hibernate.search.engine.search.loading.spi.LoadingResult;
 import org.hibernate.search.engine.search.loading.spi.ProjectionHitMapper;
@@ -26,6 +27,10 @@ public String toString() {
 
 	@Override
 	public Extractor<?, JsonObject> request(JsonObject requestBody, ProjectionRequestContext context) {
+		context.checkNotNested(
+				ElasticsearchProjectionTypeKeys.JSON_HIT,
+				ElasticsearchSearchHints.INSTANCE.jsonHitProjectionNestingNotSupportedHint()
+		);
 		return this;
 	}
 

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchProjectionTypeKeys.java

@@ -0,0 +1,22 @@
+/*
+ * Hibernate Search, full-text search for your domain model
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.search.backend.elasticsearch.search.projection.impl;
+
+import static org.hibernate.search.engine.search.projection.spi.ProjectionTypeKeys.key;
+
+import org.hibernate.search.engine.search.common.spi.SearchQueryElementTypeKey;
+
+public final class ElasticsearchProjectionTypeKeys {
+
+	private ElasticsearchProjectionTypeKeys() {
+	}
+
+	public static final SearchQueryElementTypeKey<?> JSON_HIT = key( "json-hit" );
+	public static final SearchQueryElementTypeKey<?> SOURCE = key( "source" );
+	public static final SearchQueryElementTypeKey<?> EXPLANATION = key( "explanation" );
+
+}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchScoreProjection.java

@@ -7,9 +7,11 @@
 package org.hibernate.search.backend.elasticsearch.search.projection.impl;
 
 import org.hibernate.search.backend.elasticsearch.gson.impl.JsonAccessor;
+import org.hibernate.search.backend.elasticsearch.reporting.impl.ElasticsearchSearchHints;
 import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexScope;
 import org.hibernate.search.engine.search.loading.spi.LoadingResult;
 import org.hibernate.search.engine.search.loading.spi.ProjectionHitMapper;
+import org.hibernate.search.engine.search.projection.spi.ProjectionTypeKeys;
 
 import com.google.gson.JsonObject;
 
@@ -30,6 +32,10 @@ public String toString() {
 
 	@Override
 	public Extractor<?, Float> request(JsonObject requestBody, ProjectionRequestContext context) {
+		context.checkNotNested(
+				ProjectionTypeKeys.SCORE,
+				ElasticsearchSearchHints.INSTANCE.scoreProjectionNestingNotSupportedHint()
+		);
 		TRACK_SCORES_ACCESSOR.set( requestBody, true );
 		return this;
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchSearchProjectionBuilderFactory.java

@@ -73,6 +73,12 @@ public <T> SearchProjection<T> constant(T value) {
 		return new ElasticsearchConstantProjection<>( scope, value );
 	}
 
+	@Override
+	public <T> SearchProjection<T> entityComposite(SearchProjection<T> delegate) {
+		return new ElasticsearchEntityCompositeProjection<>(
+				scope, ElasticsearchSearchProjection.from( scope, delegate ) );
+	}
+
 	@Override
 	public <T> SearchProjection<T> throwing(Supplier<SearchException> exceptionSupplier) {
 		return new ElasticsearchThrowingProjection<>( scope, exceptionSupplier );

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchSourceProjection.java

@@ -8,6 +8,7 @@
 
 import org.hibernate.search.backend.elasticsearch.gson.impl.JsonAccessor;
 import org.hibernate.search.backend.elasticsearch.gson.impl.JsonArrayAccessor;
+import org.hibernate.search.backend.elasticsearch.reporting.impl.ElasticsearchSearchHints;
 import org.hibernate.search.backend.elasticsearch.search.common.impl.ElasticsearchSearchIndexScope;
 import org.hibernate.search.engine.search.loading.spi.LoadingResult;
 import org.hibernate.search.engine.search.loading.spi.ProjectionHitMapper;
@@ -32,6 +33,10 @@ public String toString() {
 
 	@Override
 	public Extractor<?, JsonObject> request(JsonObject requestBody, ProjectionRequestContext context) {
+		context.checkNotNested(
+				ElasticsearchProjectionTypeKeys.SOURCE,
+				ElasticsearchSearchHints.INSTANCE.sourceProjectionNestingNotSupportedHint()
+		);
 		REQUEST_SOURCE_ACCESSOR.addElementIfAbsent( requestBody, WILDCARD_ALL );
 		return this;
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/FieldProjectionRequestContext.java

@@ -11,6 +11,8 @@
 
 import org.hibernate.search.backend.elasticsearch.logging.impl.Log;
 import org.hibernate.search.engine.backend.common.spi.FieldPaths;
+import org.hibernate.search.engine.reporting.spi.EventContexts;
+import org.hibernate.search.engine.search.common.spi.SearchQueryElementTypeKey;
 import org.hibernate.search.util.common.logging.impl.LoggerFactory;
 
 public class FieldProjectionRequestContext implements ProjectionRequestContext {
@@ -45,6 +47,17 @@ public void checkValidField(String absoluteFieldPath) {
 		}
 	}
 
+	@Override
+	public void checkNotNested(SearchQueryElementTypeKey<?> projectionKey, String hint) {
+		if ( absoluteCurrentFieldPath() != null ) {
+			throw log.cannotUseProjectionInNestedContext(
+					projectionKey.toString(),
+					hint,
+					EventContexts.fromIndexFieldAbsolutePath( absoluteCurrentFieldPath() )
+			);
+		}
+	}
+
 	@Override
 	public ProjectionRequestRootContext root() {
 		return root;

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ProjectionRequestContext.java

@@ -6,10 +6,14 @@
  */
 package org.hibernate.search.backend.elasticsearch.search.projection.impl;
 
+import org.hibernate.search.engine.search.common.spi.SearchQueryElementTypeKey;
+
 public interface ProjectionRequestContext {
 
 	void checkValidField(String absoluteFieldPath);
 
+	void checkNotNested(SearchQueryElementTypeKey<?> projectionKey, String hint);
+
 	ProjectionRequestRootContext root();
 
 	ProjectionRequestContext forField(String absoluteFieldPath, String[] absoluteFieldPathComponents);

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/query/impl/ElasticsearchSearchQueryRequestContext.java

@@ -22,6 +22,7 @@
 import org.hibernate.search.backend.elasticsearch.search.projection.impl.ProjectionRequestContext;
 import org.hibernate.search.backend.elasticsearch.search.projection.impl.ProjectionRequestRootContext;
 import org.hibernate.search.engine.backend.session.spi.BackendSessionContext;
+import org.hibernate.search.engine.search.common.spi.SearchQueryElementTypeKey;
 import org.hibernate.search.engine.search.loading.spi.SearchLoadingContext;
 import org.hibernate.search.engine.spatial.GeoPoint;
 import org.hibernate.search.util.common.logging.impl.LoggerFactory;
@@ -92,6 +93,11 @@ public void checkValidField(String absoluteFieldPath) {
 		// All fields are valid at the root.
 	}
 
+	@Override
+	public void checkNotNested(SearchQueryElementTypeKey<?> projectionKey, String hint) {
+		// root is not nested
+	}
+
 	@Override
 	public ProjectionRequestRootContext root() {
 		return this;

backend/lucene/src/main/java/org/hibernate/search/backend/lucene/logging/impl/Log.java

@@ -709,4 +709,8 @@ SearchException cannotHighlightInNestedContext(String currentNestingField,
 	@Message(id = ID_OFFSET + 173,
 			value = "The highlight projection cannot be applied to a field from an object using `ObjectStructure.NESTED` structure.")
 	SearchException cannotHighlightFieldFromNestedObjectStructure(@Param EventContext eventContext);
+
+	@Message(id = ID_OFFSET + 174, value = "'%1$s' cannot be nested in an object projection. "
+			+ "%2$s")
+	SearchException cannotUseProjectionInNestedContext(String projection, String hint, @Param EventContext eventContext);
 }

backend/lucene/src/main/java/org/hibernate/search/backend/lucene/reporting/impl/LuceneSearchHints.java

@@ -0,0 +1,23 @@
+/*
+ * Hibernate Search, full-text search for your domain model
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.search.backend.lucene.reporting.impl;
+
+import org.hibernate.search.engine.backend.reporting.spi.BackendSearchHints;
+import org.hibernate.search.util.common.logging.impl.MessageConstants;
+
+import org.jboss.logging.Messages;
+import org.jboss.logging.annotations.Message;
+import org.jboss.logging.annotations.MessageBundle;
+
+@MessageBundle(projectCode = MessageConstants.PROJECT_CODE)
+public interface LuceneSearchHints extends BackendSearchHints {
+
+	LuceneSearchHints INSTANCE = Messages.getBundle( LuceneSearchHints.class );
+
+	@Message("A document projection represents a root document and adding it as a part of the nested object projection might produce misleading results.")
+	String documentProjectionNestingNotSupportedHint();
+}

backend/lucene/src/main/java/org/hibernate/search/backend/lucene/search/projection/impl/LuceneDocumentProjection.java

@@ -6,6 +6,7 @@
  */
 package org.hibernate.search.backend.lucene.search.projection.impl;
 
+import org.hibernate.search.backend.lucene.reporting.impl.LuceneSearchHints;
 import org.hibernate.search.backend.lucene.lowlevel.collector.impl.StoredFieldsValuesDelegate;
 import org.hibernate.search.backend.lucene.lowlevel.collector.impl.Values;
 import org.hibernate.search.backend.lucene.search.common.impl.LuceneSearchIndexScope;
@@ -28,6 +29,10 @@ public String toString() {
 
 	@Override
 	public Extractor<?, Document> request(ProjectionRequestContext context) {
+		context.checkNotNested(
+				LuceneProjectionTypeKeys.DOCUMENT,
+				LuceneSearchHints.INSTANCE.documentProjectionNestingNotSupportedHint()
+		);
 		context.requireAllStoredFields();
 		return this;
 	}