HHH-15060 - Associations with @NotFound should always be left joined when de-referenced in HQL/Criteria

- `@NotFound` no longer exports a physical foreign-key
- tests showing bugs and inconsistencies wrt `@NotFound` handling
- added `FetchNotFoundException`
- consider a to-one nullable if either:
    - explicitly marked nullable
    - `@NotFound` is specified, whether IGNORE or EXCEPTION
- force association to EAGER

Author: sebersole

hibernate-core/src/main/java/org/hibernate/type/ManyToOneType.java

@@ -19,7 +19,12 @@
 import org.hibernate.annotations.NotFoundAction;
 import org.hibernate.engine.internal.ForeignKeys;
 import org.hibernate.engine.jdbc.Size;
-import org.hibernate.engine.spi.*;
+import org.hibernate.engine.spi.EntityEntry;
+import org.hibernate.engine.spi.EntityKey;
+import org.hibernate.engine.spi.EntityUniqueKey;
+import org.hibernate.engine.spi.Mapping;
+import org.hibernate.engine.spi.PersistenceContext;
+import org.hibernate.engine.spi.SharedSessionContractImplementor;
 import org.hibernate.persister.entity.EntityPersister;
 import org.hibernate.persister.entity.Loadable;
 
@@ -30,6 +35,7 @@
  */
 public class ManyToOneType extends EntityType {
 	private final String propertyName;
+	private final boolean nullable;
 	private final NotFoundAction notFoundAction;
 	private boolean isLogicalOneToOne;
 
@@ -57,7 +63,7 @@ public ManyToOneType(TypeFactory.TypeScope scope, String referencedEntityName, b
 
 
 	/**
-	 * @deprecated Use {@link #ManyToOneType(TypeFactory.TypeScope, String, boolean, String, String, boolean, boolean, NotFoundAction, boolean ) } instead.
+	 * @deprecated Use {@link #ManyToOneType(TypeFactory.TypeScope, String, boolean, String, String, boolean, boolean, boolean, NotFoundAction, boolean ) } instead.
 	 */
 	@Deprecated
 	public ManyToOneType(
@@ -73,7 +79,7 @@ public ManyToOneType(
 	}
 
 	/**
-	 * @deprecated Use {@link #ManyToOneType(TypeFactory.TypeScope, String, boolean, String, String, boolean, boolean, NotFoundAction, boolean ) } instead.
+	 * @deprecated Use {@link #ManyToOneType(TypeFactory.TypeScope, String, boolean, String, String, boolean, boolean, boolean, NotFoundAction, boolean ) } instead.
 	 */
 	@Deprecated
 	public ManyToOneType(
@@ -85,7 +91,18 @@ public ManyToOneType(
 			boolean unwrapProxy,
 			NotFoundAction notFoundAction,
 			boolean isLogicalOneToOne) {
-		this( scope, referencedEntityName, referenceToPrimaryKey, uniqueKeyPropertyName, null, lazy, unwrapProxy, notFoundAction, isLogicalOneToOne );
+		this(
+				scope,
+				referencedEntityName,
+				referenceToPrimaryKey,
+				uniqueKeyPropertyName,
+				null,
+				notFoundAction != null,
+				lazy,
+				unwrapProxy,
+				notFoundAction,
+				isLogicalOneToOne
+		);
 	}
 
 	public ManyToOneType(
@@ -94,13 +111,15 @@ public ManyToOneType(
 			boolean referenceToPrimaryKey,
 			String uniqueKeyPropertyName,
 			String propertyName,
+			boolean nullable,
 			boolean lazy,
 			boolean unwrapProxy,
 			NotFoundAction notFoundAction,
 			boolean isLogicalOneToOne) {
 		super( scope, referencedEntityName, referenceToPrimaryKey, uniqueKeyPropertyName, !lazy, unwrapProxy );
 		this.propertyName = propertyName;
 		this.notFoundAction = notFoundAction;
+		this.nullable = nullable;
 		this.isLogicalOneToOne = isLogicalOneToOne;
 	}
 
@@ -109,12 +128,12 @@ public ManyToOneType(ManyToOneType original, String superTypeEntityName) {
 		this.propertyName = original.propertyName;
 		this.notFoundAction = original.notFoundAction;
 		this.isLogicalOneToOne = original.isLogicalOneToOne;
+		this.nullable = original.nullable;
 	}
 
 	@Override
 	public boolean isNullable() {
-		// this matches the original check, but this seems wrong.
-		return notFoundAction == NotFoundAction.IGNORE;
+		return notFoundAction != null;
 	}
 
 	@Override

hibernate-core/src/main/java/org/hibernate/type/TypeFactory.java

@@ -356,6 +356,31 @@ public EntityType manyToOne(
 				referenceToPrimaryKey,
 				uniqueKeyPropertyName,
 				propertyName,
+				notFoundAction != null,
+				lazy,
+				unwrapProxy,
+				notFoundAction,
+				isLogicalOneToOne
+		);
+	}
+
+	public EntityType manyToOne(
+			String persistentClass,
+			boolean referenceToPrimaryKey,
+			String uniqueKeyPropertyName,
+			String propertyName,
+			boolean nullable,
+			boolean lazy,
+			boolean unwrapProxy,
+			NotFoundAction notFoundAction,
+			boolean isLogicalOneToOne) {
+		return new ManyToOneType(
+				typeScope,
+				persistentClass,
+				referenceToPrimaryKey,
+				uniqueKeyPropertyName,
+				propertyName,
+				nullable,
 				lazy,
 				unwrapProxy,
 				notFoundAction,