fix: autogenerate id if null (#5884)

Author: wolf4ood

spi/control-plane-spi/src/main/java/org/eclipse/edc/policy/cel/model/CelExpression.java

@@ -19,6 +19,7 @@
 import java.util.HashSet;
 import java.util.Objects;
 import java.util.Set;
+import java.util.UUID;
 
 import static org.eclipse.edc.spi.constants.CoreConstants.EDC_NAMESPACE;
 
@@ -126,6 +127,9 @@ public Builder updatedAt(Long updatedAt) {
         @Override
         public CelExpression build() {
             super.build();
+            if (entity.getId() == null) {
+                id(UUID.randomUUID().toString());
+            }
             Objects.requireNonNull(entity.leftOperand, "CelExpression leftOperand cannot be null");
             Objects.requireNonNull(entity.expression, "CelExpression expression cannot be null");
             Objects.requireNonNull(entity.description, "CelExpression description cannot be null");

spi/control-plane-spi/src/test/java/org/eclipse/edc/policy/cel/model/CelExpressionTest.java

@@ -0,0 +1,66 @@
+/*
+ *  Copyright (c) 2026 Metaform Systems, Inc.
+ *
+ *  This program and the accompanying materials are made available under the
+ *  terms of the Apache License, Version 2.0 which is available at
+ *  https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Contributors:
+ *       Metaform Systems, Inc. - initial API and implementation
+ *
+ */
+
+package org.eclipse.edc.policy.cel.model;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.UUID;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatCode;
+
+class CelExpressionTest {
+
+    @Test
+    void build_whenIdNotProvided_shouldGenerateUuid() {
+        var expression = CelExpression.Builder.newInstance()
+                .leftOperand("leftOperand")
+                .expression("true")
+                .description("description")
+                .build();
+
+        assertThat(expression.getId()).isNotNull();
+        assertThatCode(() -> UUID.fromString(expression.getId())).doesNotThrowAnyException();
+    }
+
+    @Test
+    void build_whenIdProvided_shouldKeepIt() {
+        var expression = CelExpression.Builder.newInstance()
+                .id("my-id")
+                .leftOperand("leftOperand")
+                .expression("true")
+                .description("description")
+                .build();
+
+        assertThat(expression.getId()).isEqualTo("my-id");
+    }
+
+    @Test
+    void build_whenBuiltTwice_shouldGenerateDifferentIds() {
+        var first = CelExpression.Builder.newInstance()
+                .leftOperand("leftOperand")
+                .expression("true")
+                .description("description")
+                .build();
+
+        var second = CelExpression.Builder.newInstance()
+                .leftOperand("leftOperand")
+                .expression("true")
+                .description("description")
+                .build();
+
+        assertThat(first.getId()).isNotEqualTo(second.getId());
+    }
+}