Fix embedded ID relation response schemas

springdoc-openapi-starter-common/src/main/java/org/springdoc/core/utils/SpringDocDataRestUtils.java

@@ -99,6 +99,11 @@ public class SpringDocDataRestUtils {
 	 */
 	private final HashMap<String, EntityInfo> entityInoMap = new HashMap();
 
+	/**
+	 * The associations fields by entity.
+	 */
+	private final HashMap<String, List<String>> allAssociationsFieldsMap = new HashMap<>();
+
 	/**
 	 * The Repository rest configuration.
 	 */
@@ -136,6 +141,7 @@ public void customise(OpenAPI openAPI, ResourceMappings mappings, PersistentEnti
 				entityInfo.setIgnoredFields(ignoredFields);
 			List<String> associationsFields = getAssociationsFields(resourceMetadata, entity);
 			entityInfo.setAssociationsFields(associationsFields);
+			allAssociationsFieldsMap.put(domainType.getSimpleName(), getAllAssociationsFields(resourceMetadata, entity));
 			entityInoMap.put(domainType.getSimpleName(), entityInfo);
 		}
 
@@ -277,11 +283,43 @@ private Schema updateResponseSchema(String className, Schema existingSchema, Com
 				else if (EMBEDDED.equals(propId)) {
 					updateResponseSchemaEmbedded(components, entityInfo, entry, openapi31);
 				}
+				else if (allAssociationsFieldsMap.get(className).contains(propId)) {
+					updateResponseSchemaProperty(entry.getValue(), components, openapi31);
+				}
 			}
 		}
 		return existingSchema;
 	}
 
+	/**
+	 * Update a response schema property that points to an entity which is not an
+	 * exported repository. Spring Data REST serializes these associations in
+	 * the containing representation, so they need the same association filtering
+	 * as an exported entity response.
+	 *
+	 * @param property   the property
+	 * @param components the components
+	 * @param openapi31  the openapi 31
+	 */
+	private void updateResponseSchemaProperty(Schema property, Components components, boolean openapi31) {
+		if (property == null)
+			return;
+		if (property.get$ref() != null && !property.get$ref().endsWith(RESPONSE)) {
+			String key = property.get$ref().substring(Components.COMPONENTS_SCHEMAS_REF.length());
+			if (entityInoMap.containsKey(key)) {
+				String newKey = property.get$ref() + RESPONSE;
+				if (!components.getSchemas().containsKey(key + RESPONSE)) {
+					createNewResponseSchema(key, components, openapi31);
+					updateResponseSchema(key, components.getSchemas().get(key + RESPONSE), components, openapi31);
+				}
+				property.set$ref(newKey);
+			}
+		}
+		else if (property.getItems() != null) {
+			updateResponseSchemaProperty(property.getItems(), components, openapi31);
+		}
+	}
+
 	/**
 	 * Update response schema embedded.
 	 *
@@ -447,6 +485,25 @@ private List<String> getAssociationsFields(ResourceMetadata
 		return associationsFields;
 	}
 
+	/**
+	 * Gets all associations fields.
+	 *
+	 * @param resourceMetadata the resource metadata
+	 * @param entity           the entity
+	 * @return all associations fields
+	 */
+	private List<String> getAllAssociationsFields(ResourceMetadata
+			resourceMetadata, PersistentEntity<?, ?> entity) {
+		List<String> associationsFields = new ArrayList<>();
+		entity.doWithAssociations((SimpleAssociationHandler) association -> {
+			PersistentProperty<?> property = association.getInverse();
+			ResourceMapping mapping = resourceMetadata.getMappingFor(property);
+			String fieldName = mapping.getRel().value();
+			associationsFields.add(fieldName);
+		});
+		return associationsFields;
+	}
+
 	/**
 	 * Gets ignored fields.
 	 *

springdoc-openapi-tests/springdoc-openapi-data-rest-tests/src/test/java/test/org/springdoc/api/v31/app40/Goal.java

@@ -0,0 +1,59 @@
+/*
+ *
+ *  * Copyright 2019-2026 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 test.org.springdoc.api.v31.app40;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import jakarta.persistence.CascadeType;
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.OneToMany;
+
+/**
+ * Aggregate root with a collection of composite-key join entities.
+ *
+ * @author hej090224
+ */
+@Entity
+public class Goal {
+
+	@Id
+	@GeneratedValue(strategy = GenerationType.AUTO)
+	private Long id;
+
+	private String name;
+
+	@OneToMany(mappedBy = "goal", cascade = CascadeType.ALL)
+	private Set<InitiativeImpactOnGoal> impactsByInitiatives = new HashSet<>();
+
+	public Long getId() {
+		return id;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public Set<InitiativeImpactOnGoal> getImpactsByInitiatives() {
+		return impactsByInitiatives;
+	}
+}

springdoc-openapi-tests/springdoc-openapi-data-rest-tests/src/test/java/test/org/springdoc/api/v31/app40/GoalInitiativeImpactId.java

@@ -0,0 +1,52 @@
+/*
+ *
+ *  * Copyright 2019-2026 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 test.org.springdoc.api.v31.app40;
+
+import java.io.Serializable;
+
+import jakarta.persistence.Embeddable;
+
+/**
+ * Composite identifier for the join entity used by the issue reproducer.
+ *
+ * @author hej090224
+ */
+@Embeddable
+public class GoalInitiativeImpactId implements Serializable {
+
+	private Long goalId;
+
+	private Long initiativeId;
+
+	public Long getGoalId() {
+		return goalId;
+	}
+
+	public void setGoalId(Long goalId) {
+		this.goalId = goalId;
+	}
+
+	public Long getInitiativeId() {
+		return initiativeId;
+	}
+
+	public void setInitiativeId(Long initiativeId) {
+		this.initiativeId = initiativeId;
+	}
+}

springdoc-openapi-tests/springdoc-openapi-data-rest-tests/src/test/java/test/org/springdoc/api/v31/app40/GoalRepository.java

@@ -0,0 +1,31 @@
+/*
+ *
+ *  * Copyright 2019-2026 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 test.org.springdoc.api.v31.app40;
+
+import org.springframework.data.repository.CrudRepository;
+import org.springframework.data.rest.core.annotation.RepositoryRestResource;
+
+/**
+ * Spring Data REST repository for the issue reproducer aggregate.
+ *
+ * @author hej090224
+ */
+@RepositoryRestResource
+public interface GoalRepository extends CrudRepository<Goal, Long> {
+}

springdoc-openapi-tests/springdoc-openapi-data-rest-tests/src/test/java/test/org/springdoc/api/v31/app40/Initiative.java

@@ -0,0 +1,47 @@
+/*
+ *
+ *  * Copyright 2019-2026 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 test.org.springdoc.api.v31.app40;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+
+/**
+ * Entity referenced by the composite-key join entity.
+ *
+ * @author hej090224
+ */
+@Entity
+public class Initiative {
+
+	@Id
+	@GeneratedValue(strategy = GenerationType.AUTO)
+	private Long id;
+
+	private String name;
+
+	public Long getId() {
+		return id;
+	}
+
+	public String getName() {
+		return name;
+	}
+}

springdoc-openapi-tests/springdoc-openapi-data-rest-tests/src/test/java/test/org/springdoc/api/v31/app40/InitiativeImpactOnGoal.java

@@ -0,0 +1,73 @@
+/*
+ *
+ *  * Copyright 2019-2026 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 test.org.springdoc.api.v31.app40;
+
+import jakarta.persistence.EmbeddedId;
+import jakarta.persistence.Entity;
+import jakarta.persistence.EnumType;
+import jakarta.persistence.Enumerated;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.MapsId;
+
+/**
+ * Join entity combining an embedded identifier with two mapped associations.
+ *
+ * @author hej090224
+ */
+@Entity
+public class InitiativeImpactOnGoal {
+
+	@EmbeddedId
+	private GoalInitiativeImpactId id;
+
+	@ManyToOne
+	@MapsId("goalId")
+	@JoinColumn(name = "goal_id")
+	private Goal goal;
+
+	@ManyToOne
+	@MapsId("initiativeId")
+	@JoinColumn(name = "initiative_id")
+	private Initiative initiative;
+
+	@Enumerated(EnumType.STRING)
+	private ImpactLevel impactLevel;
+
+	public GoalInitiativeImpactId getId() {
+		return id;
+	}
+
+	public Goal getGoal() {
+		return goal;
+	}
+
+	public Initiative getInitiative() {
+		return initiative;
+	}
+
+	public ImpactLevel getImpactLevel() {
+		return impactLevel;
+	}
+
+	enum ImpactLevel {
+		TRIVIAL,
+		SIGNIFICANT
+	}
+}

springdoc-openapi-tests/springdoc-openapi-data-rest-tests/src/test/java/test/org/springdoc/api/v31/app40/InitiativeRepository.java

@@ -0,0 +1,31 @@
+/*
+ *
+ *  * Copyright 2019-2026 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 test.org.springdoc.api.v31.app40;
+
+import org.springframework.data.repository.CrudRepository;
+import org.springframework.data.rest.core.annotation.RepositoryRestResource;
+
+/**
+ * Spring Data REST repository for initiatives.
+ *
+ * @author hej090224
+ */
+@RepositoryRestResource
+public interface InitiativeRepository extends CrudRepository<Initiative, Long> {
+}