HHH-16766: Load lazy hierarchical IdClass entities

hibernate-core/src/main/java/org/hibernate/event/internal/DefaultLoadEventListener.java

@@ -146,7 +146,7 @@ private boolean handleIdType(EntityPersister persister, LoadEvent event, LoadTyp
 						return false;
 					}
 					else {
-						return true;
+						return !idClass.isInstance( event.getEntityId() );
 					}
 				}
 				else {

hibernate-core/src/main/java/org/hibernate/metamodel/mapping/internal/NonAggregatedIdentifierMappingImpl.java

@@ -26,6 +26,8 @@
 import org.hibernate.metamodel.mapping.NonAggregatedIdentifierMapping;
 import org.hibernate.metamodel.mapping.SelectableMappings;
 import org.hibernate.persister.entity.EntityPersister;
+import org.hibernate.proxy.HibernateProxy;
+import org.hibernate.proxy.LazyInitializer;
 import org.hibernate.query.sqm.sql.SqmToSqlAstConverter;
 import org.hibernate.spi.NavigablePath;
 import org.hibernate.sql.ast.Clause;
@@ -218,6 +220,10 @@ public String getAttributeName() {
 	@Override
 	public Object getIdentifier(Object entity) {
 		if ( hasContainingClass() ) {
+			final LazyInitializer lazyInitializer = HibernateProxy.extractLazyInitializer( entity );
+			if ( lazyInitializer != null ) {
+				return lazyInitializer.getIdentifier();
+			}
 			final Object id = identifierValueMapper.getRepresentationStrategy().getInstantiator().instantiate(
 					null,
 					sessionFactory

hibernate-core/src/test/java/org/hibernate/orm/test/annotations/cid/Flight.java

@@ -0,0 +1,39 @@
+package org.hibernate.orm.test.annotations.cid;
+
+import jakarta.persistence.*;
+
+import java.util.List;
+
+@Entity
+@Table(name = "flight")
+public class Flight {
+
+    @Id
+    @Column(name = "id")
+    private Integer id;
+
+    @OneToMany(mappedBy = "flight", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
+    private List<FlightSegment> segments;
+
+    public Integer getId() {
+        return id;
+    }
+
+    public void setId(Integer id) {
+        this.id = id;
+    }
+
+    public List<FlightSegment> getSegments() {
+        return segments;
+    }
+
+    public void setSegments(List<FlightSegment> segments) {
+        this.segments = segments;
+    }
+
+    public void addSegment(FlightSegment segment) {
+        segment.setFlight(this);
+        segments.add(segment);
+    }
+
+}

hibernate-core/src/test/java/org/hibernate/orm/test/annotations/cid/FlightSegment.java

@@ -0,0 +1,47 @@
+package org.hibernate.orm.test.annotations.cid;
+
+import jakarta.persistence.*;
+
+@Entity
+@IdClass(FlightSegmentId.class)
+@Table(name = "flight_segment")
+public class FlightSegment {
+
+    @Id
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "flight_id", nullable = false)
+    private Flight flight;
+
+    @Id
+    @Column(name = "segment_number")
+    private Integer segmentNumber;
+
+    @OneToOne(mappedBy = "segment", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
+    private FlightSegmentConfiguration configuration;
+
+    public Flight getFlight() {
+        return flight;
+    }
+
+    public void setFlight(Flight flight) {
+        this.flight = flight;
+    }
+
+    public Integer getSegmentNumber() {
+        return segmentNumber;
+    }
+
+    public void setSegmentNumber(Integer segmentNumber) {
+        this.segmentNumber = segmentNumber;
+    }
+
+    public FlightSegmentConfiguration getConfiguration() {
+        return configuration;
+    }
+
+    public void setConfiguration(FlightSegmentConfiguration configuration) {
+        configuration.setSegment(this);
+        this.configuration = configuration;
+    }
+
+}

hibernate-core/src/test/java/org/hibernate/orm/test/annotations/cid/FlightSegmentConfiguration.java

@@ -0,0 +1,24 @@
+package org.hibernate.orm.test.annotations.cid;
+
+import jakarta.persistence.*;
+
+@Entity
+@IdClass(FlightSegmentConfigurationId.class)
+@Table(name = "flight_segment_configuration")
+public class FlightSegmentConfiguration {
+
+    @Id
+    @OneToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "flight_id", referencedColumnName = "flight_id", nullable = false)
+    @JoinColumn(name = "segment_number", referencedColumnName = "segment_number", nullable = false)
+    private FlightSegment segment;
+
+    public FlightSegment getSegment() {
+        return segment;
+    }
+
+    public void setSegment(FlightSegment segment) {
+        this.segment = segment;
+    }
+
+}

hibernate-core/src/test/java/org/hibernate/orm/test/annotations/cid/FlightSegmentConfigurationId.java

@@ -0,0 +1,46 @@
+package org.hibernate.orm.test.annotations.cid;
+
+import java.io.Serializable;
+import java.util.Objects;
+import java.util.StringJoiner;
+
+public class FlightSegmentConfigurationId implements Serializable {
+
+    private FlightSegmentId segment;
+
+    public FlightSegmentConfigurationId() {
+    }
+
+    public FlightSegmentConfigurationId(FlightSegmentId segment) {
+        this.segment = segment;
+    }
+
+    public FlightSegmentId getSegment() {
+        return segment;
+    }
+
+    public void setSegment(FlightSegmentId segment) {
+        this.segment = segment;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        FlightSegmentConfigurationId that = (FlightSegmentConfigurationId) o;
+        return Objects.equals(segment, that.segment);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(segment);
+    }
+
+    @Override
+    public String toString() {
+        return new StringJoiner(", ", FlightSegmentConfigurationId.class.getSimpleName() + "[", "]")
+                .add("segment=" + segment)
+                .toString();
+    }
+
+}

hibernate-core/src/test/java/org/hibernate/orm/test/annotations/cid/FlightSegmentId.java

@@ -0,0 +1,57 @@
+package org.hibernate.orm.test.annotations.cid;
+
+import java.io.Serializable;
+import java.util.Objects;
+import java.util.StringJoiner;
+
+public class FlightSegmentId implements Serializable {
+
+    private Integer flight;
+    private Integer segmentNumber;
+
+    public FlightSegmentId() {
+    }
+
+    public FlightSegmentId(Integer flight, Integer segmentNumber) {
+        this.flight = flight;
+        this.segmentNumber = segmentNumber;
+    }
+
+    public Integer getFlight() {
+        return flight;
+    }
+
+    public void setFlight(Integer flight) {
+        this.flight = flight;
+    }
+
+    public Integer getSegmentNumber() {
+        return segmentNumber;
+    }
+
+    public void setSegmentNumber(Integer segmentNumber) {
+        this.segmentNumber = segmentNumber;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        FlightSegmentId that = (FlightSegmentId) o;
+        return Objects.equals(flight, that.flight) && Objects.equals(segmentNumber, that.segmentNumber);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(flight, segmentNumber);
+    }
+
+    @Override
+    public String toString() {
+        return new StringJoiner(", ", FlightSegmentId.class.getSimpleName() + "[", "]")
+                .add("flight=" + flight)
+                .add("segmentNumber=" + segmentNumber)
+                .toString();
+    }
+
+}

hibernate-core/src/test/java/org/hibernate/orm/test/annotations/cid/Freight.java

@@ -0,0 +1,34 @@
+package org.hibernate.orm.test.annotations.cid;
+
+import jakarta.persistence.*;
+
+@Entity
+@Table(name = "freight")
+public class Freight {
+
+    @Id
+    @Column(name = "freight_number")
+    private Integer freightNumber;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "flight_id", referencedColumnName = "flight_id")
+    @JoinColumn(name = "segment_number", referencedColumnName = "segment_number")
+    private FlightSegment flightSegment;
+
+    public Integer getFreightNumber() {
+        return freightNumber;
+    }
+
+    public void setFreightNumber(Integer freightNumber) {
+        this.freightNumber = freightNumber;
+    }
+
+    public FlightSegment getFlightSegment() {
+        return flightSegment;
+    }
+
+    public void setFlightSegment(FlightSegment flightSegment) {
+        this.flightSegment = flightSegment;
+    }
+
+}