Apply query hints to count queries for page-based Specification.

Query hints are applied in many places, but not when doing a findAll(Specification, Pageable).

Closes #2054.
Original pull request #2528

Author: gregturn

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/SimpleJpaRepository.java

@@ -309,6 +309,13 @@ protected QueryHints getQueryHints() {
 		return metadata == null ? NoHints.INSTANCE : DefaultQueryHints.of(entityInformation, metadata);
 	}
 
+	/**
+	 * Returns {@link QueryHints} with the query hints on the current {@link CrudMethodMetadata} for count queries.
+	 */
+	protected QueryHints getQueryHintsForCount() {
+		return metadata == null ? NoHints.INSTANCE : DefaultQueryHints.of(entityInformation, metadata).forCounts();
+	}
+
 	@Deprecated
 	@Override
 	public T getOne(ID id) {
@@ -750,7 +757,7 @@ protected <S extends T> TypedQuery<Long> getCountQuery(@Nullable Specification<S
 		// Remove all Orders the Specifications might have applied
 		query.orderBy(Collections.emptyList());
 
-		return em.createQuery(query);
+		return applyRepositoryMethodMetadataForCount(em.createQuery(query));
 	}
 
 	/**
@@ -800,6 +807,21 @@ private void applyQueryHints(Query query) {
 		getQueryHints().withFetchGraphs(em).forEach(query::setHint);
 	}
 
+	private <S> TypedQuery<S> applyRepositoryMethodMetadataForCount(TypedQuery<S> query) {
+
+		if (metadata == null) {
+			return query;
+		}
+
+		applyQueryHintsForCount(query);
+
+		return query;
+	}
+
+	private void applyQueryHintsForCount(Query query) {
+		getQueryHintsForCount().forEach(query::setHint);
+	}
+
 	/**
 	 * Executes a count query and transparently sums up all values returned.
 	 *

spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/support/SimpleJpaRepositoryUnitTests.java

@@ -18,16 +18,17 @@
 import static java.util.Collections.*;
 import static org.assertj.core.api.Assertions.*;
 import static org.mockito.Mockito.*;
-
-import java.util.Arrays;
-import java.util.Optional;
+import static org.springframework.data.jpa.domain.Specification.*;
 
 import jakarta.persistence.EntityGraph;
 import jakarta.persistence.EntityManager;
 import jakarta.persistence.TypedQuery;
 import jakarta.persistence.criteria.CriteriaBuilder;
 import jakarta.persistence.criteria.CriteriaQuery;
 
+import java.util.Arrays;
+import java.util.Optional;
+
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
@@ -192,4 +193,14 @@ void doNothingWhenNonExistentInstanceGetsDeleted() {
 		verify(em, never()).remove(newUser);
 		verify(em, never()).merge(newUser);
 	}
+
+	@Test // GH-2054
+	void applyQueryHintsToCountQueriesForSpecificationPageables() {
+
+		when(query.getResultList()).thenReturn(Arrays.asList(new User(), new User()));
+
+		repo.findAll(where(null), PageRequest.of(2, 1));
+
+		verify(metadata).getQueryHintsForCount();
+	}
 }