Use implicit join to create Predicate if possible

Fix spring-projectsGH-3349

Author: quaff

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/JpaQueryCreator.java

@@ -56,6 +56,7 @@
  * @author Moritz Becker
  * @author Andrey Kovalev
  * @author Greg Turnquist
+ * @author Yanming Zhou
  */
 public class JpaQueryCreator extends AbstractQueryCreator<CriteriaQuery<? extends Object>, Predicate> {
 
@@ -384,6 +385,19 @@ private Expression<? extends Comparable> getComparablePath(Root<?> root, Part pa
 		}
 
 		private <T> Expression<T> getTypedPath(Root<?> root, Part part) {
+
+			// use implicit join if possible
+			Path<?> path = root;
+			PropertyPath property = part.getProperty();
+			while (property != null && !property.isCollection()) {
+				path = path.get(property.getSegment());
+				if (property.hasNext()) {
+					property = property.next();
+				} else {
+					return (Expression<T>) path;
+				}
+			}
+
 			return toExpressionRecursively(root, part.getProperty());
 		}
 

spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/query/JpaQueryCreatorIntegrationTests.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2017-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.jpa.repository.query;
+
+import jakarta.persistence.EntityManager;
+import jakarta.persistence.PersistenceContext;
+import jakarta.persistence.TypedQuery;
+import org.hibernate.query.spi.SqmQuery;
+import org.hibernate.query.sqm.tree.from.SqmRoot;
+import org.hibernate.query.sqm.tree.select.SqmQuerySpec;
+import org.hibernate.query.sqm.tree.select.SqmSelectStatement;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.data.jpa.domain.sample.User;
+import org.springframework.data.jpa.provider.PersistenceProvider;
+import org.springframework.data.projection.SpelAwareProxyProjectionFactory;
+import org.springframework.data.repository.Repository;
+import org.springframework.data.repository.core.support.AbstractRepositoryMetadata;
+import org.springframework.data.repository.query.parser.PartTree;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import java.lang.reflect.Method;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Integration tests for {@link JpaQueryCreator}.
+ *
+ * @author Yanming Zhou
+ */
+@ExtendWith(SpringExtension.class)
+@ContextConfiguration("classpath:infrastructure.xml")
+class JpaQueryCreatorIntegrationTests {
+
+	@PersistenceContext
+	EntityManager entityManager;
+
+	@Test // GH-3349
+	void implicitJoin() throws Exception {
+
+		Method method = SomeRepository.class.getMethod("findByManagerId", Integer.class);
+
+		PersistenceProvider provider = PersistenceProvider.fromEntityManager(entityManager);
+		JpaQueryMethod queryMethod = new JpaQueryMethod(method,
+				AbstractRepositoryMetadata.getMetadata(SomeRepository.class), new SpelAwareProxyProjectionFactory(), provider);
+
+		PartTree tree = new PartTree("findByManagerId", User.class);
+		ParameterMetadataProvider metadataProvider = new ParameterMetadataProvider(entityManager.getCriteriaBuilder(),
+				queryMethod.getParameters(), EscapeCharacter.DEFAULT);
+
+		JpaQueryCreator creator = new JpaQueryCreator(tree, queryMethod.getResultProcessor().getReturnedType(),
+				entityManager.getCriteriaBuilder(), metadataProvider);
+
+		TypedQuery<?> query = entityManager.createQuery(creator.createQuery());
+		SqmQuery sqmQuery = ((SqmQuery) query);
+		SqmSelectStatement<?> statement = (SqmSelectStatement<?>) sqmQuery.getSqmStatement();
+		SqmQuerySpec<?> spec = (SqmQuerySpec<?>) statement.getQueryPart();
+		SqmRoot<?> root = spec.getFromClause().getRoots().get(0);
+
+		assertThat(root.getJoins()).isEmpty();
+	}
+
+	interface SomeRepository extends Repository<User, Integer> {
+		List<User> findByManagerId(Integer managerId);
+	}
+}