HHH-17825 fix npe for single-column @UniqueConstraint

Note that HHH-17132 already attempted to fix the reported
problem, but the fix introduced a new bug, and NPE.

hibernate-core/src/main/java/org/hibernate/dialect/unique/CreateTableUniqueDelegate.java

@@ -80,10 +80,21 @@ public class CreateTableUniqueDelegate extends AlterTableUniqueDelegate {
 	}
 
 	private static boolean isSingleColumnUnique(Table table, UniqueKey uniqueKey) {
-		return uniqueKey.getColumns().size() == 1
+		if ( uniqueKey.getColumns().size() == 1)  {
-				// Since columns are created on demand in IndexBinder.createColumn,
+			// Since columns are created on demand in IndexBinder.createColumn,
-				// we also have to check if the "real" column is unique to be safe
+			// we also have to check if the "real" column is unique to be safe
-				&& ( uniqueKey.getColumn( 0 ).isUnique() || table.getColumn( uniqueKey.getColumn( 0 ) ).isUnique() );
+			final Column uniqueKeyColumn = uniqueKey.getColumn(0);
+			if ( uniqueKeyColumn.isUnique() ) {
+				return true;
+			}
+			else {
+				final Column column = table.getColumn( uniqueKeyColumn );
+				return column != null && column.isUnique();
+			}
+		}
+		else {
+			return false;
+		}
 	}
 
 	@Override

hibernate-core/src/test/java/org/hibernate/orm/test/schemaupdate/uniqueconstraint/MultiUniqueConstraintNameTest.java

@@ -0,0 +1,61 @@
+package org.hibernate.orm.test.schemaupdate.uniqueconstraint;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.Id;
+import jakarta.persistence.Index;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.OneToOne;
+import jakarta.persistence.Table;
+import jakarta.persistence.UniqueConstraint;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.Test;
+
+@SessionFactory
+@DomainModel(annotatedClasses = {MultiUniqueConstraintNameTest.MyEntity.class, MultiUniqueConstraintNameTest.MyOtherEntity.class})
+public class MultiUniqueConstraintNameTest {
+
+	@Test void test(SessionFactoryScope scope) {
+		scope.getSessionFactory();
+	}
+
+	@Entity
+	@Table(name = "my_entity",
+			uniqueConstraints =
+					@UniqueConstraint(
+							name = "my_other_entity_id_unique",
+							columnNames = {"my_other_entity_id1","my_other_entity_id2"}
+					),
+			indexes = @Index(name = "some_long_index", columnList = "some_long"))
+	static class MyEntity {
+
+		@Id
+		long id1;
+		@Id
+		long id2;
+
+		@OneToOne(fetch = FetchType.LAZY, optional = false)
+		@JoinColumn(name = "my_other_entity_id1")
+		@JoinColumn(name = "my_other_entity_id2")
+		private MyOtherEntity myOtherEntity;
+
+		@Column(name = "some_long")
+		private long someLong;
+
+	}
+
+	@Entity
+	@Table(name = "my_other_entity")
+	static class MyOtherEntity {
+		@Id
+		long id1;
+		@Id
+		long id2;
+
+		@Column(name = "some_string")
+		private String someString;
+	}
+}

hibernate-core/src/test/java/org/hibernate/orm/test/schemaupdate/uniqueconstraint/UniqueConstraintNameTest.java

@@ -0,0 +1,65 @@
+package org.hibernate.orm.test.schemaupdate.uniqueconstraint;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.ForeignKey;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.Id;
+import jakarta.persistence.Index;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.OneToOne;
+import jakarta.persistence.Table;
+import jakarta.persistence.UniqueConstraint;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.Test;
+
+@SessionFactory
+@DomainModel(annotatedClasses = {UniqueConstraintNameTest.MyEntity.class, UniqueConstraintNameTest.MyOtherEntity.class})
+@JiraKey("HHH-17825")
+@JiraKey("HHH-17132")
+public class UniqueConstraintNameTest {
+
+	@Test void test(SessionFactoryScope scope) {
+		scope.getSessionFactory();
+	}
+
+	@Entity
+	@Table(name = "my_entity",
+			uniqueConstraints =
+					@UniqueConstraint(
+							name = "my_other_entity_id_unique",
+							columnNames = "my_other_entity_id"
+					),
+			indexes = @Index(name = "some_long_index", columnList = "some_long"))
+	static class MyEntity {
+
+		@Id
+		@GeneratedValue
+		long id;
+
+		@OneToOne(fetch = FetchType.LAZY, optional = false)
+		@JoinColumn(name = "my_other_entity_id",
+				updatable = false,
+				foreignKey = @ForeignKey(name = "FK_moe"))
+		private MyOtherEntity myOtherEntity;
+
+		@Column(name = "some_long")
+		private long someLong;
+
+	}
+
+	@Entity
+	@Table(name = "my_other_entity")
+	static class MyOtherEntity {
+		@Id
+		@GeneratedValue
+		long id;
+
+		@Column(name = "some_string")
+		private String someString;
+	}
+}