From feed0298c4f94468edbe92e0c1345d76341e6529 Mon Sep 17 00:00:00 2001
From: Maciej Barelkowski <maciej.barelkowski@camunda.com>
Date: Fri, 13 Dec 2024 17:12:26 +0100
Subject: [PATCH] fix: accept empty script expression without error

Related to https://github.com/camunda/camunda-modeler/issues/4759
---
 lib/zeebe/util/feelUtility.js                 |  4 +-
 .../script-task-empty-expression.bpmn         | 17 +++++
 test/fixtures/zeebe/mappings/script-task.bpmn |  4 +-
 test/spec/zeebe/Mappings.spec.js              | 62 +++++++++++++------
 4 files changed, 65 insertions(+), 22 deletions(-)
 create mode 100644 test/fixtures/zeebe/mappings/script-task-empty-expression.bpmn

diff --git a/lib/zeebe/util/feelUtility.js b/lib/zeebe/util/feelUtility.js
index f140dc2..57c89b5 100644
--- a/lib/zeebe/util/feelUtility.js
+++ b/lib/zeebe/util/feelUtility.js
@@ -213,12 +213,12 @@ function getIoExpression(variable, origin) {
  *
  * @param {ProcessVariable} variable
  * @param {djs.model.Base} origin
- * @returns { expression: String}
+ * @returns {string}
  */
 function getScriptExpression(variable, origin) {
   const script = getExtensionElementsList(origin, 'zeebe:Script')[0];
 
-  if (!script) {
+  if (!script || !script.expression) {
     return;
   }
 
diff --git a/test/fixtures/zeebe/mappings/script-task-empty-expression.bpmn b/test/fixtures/zeebe/mappings/script-task-empty-expression.bpmn
new file mode 100644
index 0000000..64cd8c4
--- /dev/null
+++ b/test/fixtures/zeebe/mappings/script-task-empty-expression.bpmn
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:zeebe="http://camunda.org/schema/zeebe/1.0" xmlns:modeler="http://camunda.org/schema/modeler/1.0" id="Definitions_0qieuld" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="5.28.0" modeler:executionPlatform="Camunda Cloud" modeler:executionPlatformVersion="8.6.0">
+  <bpmn:process id="Process_1" isExecutable="true">
+    <bpmn:scriptTask id="ScriptTask" name="Script Task">
+      <bpmn:extensionElements>
+        <zeebe:script resultVariable="scriptResult" />
+      </bpmn:extensionElements>
+    </bpmn:scriptTask>
+  </bpmn:process>
+  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
+    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1">
+      <bpmndi:BPMNShape id="Activity_1g8b868_di" bpmnElement="ScriptTask">
+        <dc:Bounds x="160" y="80" width="100" height="80" />
+      </bpmndi:BPMNShape>
+    </bpmndi:BPMNPlane>
+  </bpmndi:BPMNDiagram>
+</bpmn:definitions>
\ No newline at end of file
diff --git a/test/fixtures/zeebe/mappings/script-task.bpmn b/test/fixtures/zeebe/mappings/script-task.bpmn
index a5cc86a..9fc5421 100644
--- a/test/fixtures/zeebe/mappings/script-task.bpmn
+++ b/test/fixtures/zeebe/mappings/script-task.bpmn
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:zeebe="http://camunda.org/schema/zeebe/1.0" xmlns:modeler="http://camunda.org/schema/modeler/1.0" id="Definitions_0qieuld" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="5.28.0" modeler:executionPlatform="Camunda Cloud" modeler:executionPlatformVersion="8.6.0">
   <bpmn:process id="Process_1" isExecutable="true">
-    <bpmn:scriptTask id="Activity_0kxqawv" name="Script Task">
+    <bpmn:scriptTask id="ScriptTask" name="Script Task">
       <bpmn:extensionElements>
         <zeebe:script expression="={&#10;  foo: 123&#10;}" resultVariable="scriptResult" />
       </bpmn:extensionElements>
@@ -9,7 +9,7 @@
   </bpmn:process>
   <bpmndi:BPMNDiagram id="BPMNDiagram_1">
     <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1">
-      <bpmndi:BPMNShape id="Activity_1g8b868_di" bpmnElement="Activity_0kxqawv">
+      <bpmndi:BPMNShape id="Activity_1g8b868_di" bpmnElement="ScriptTask">
         <dc:Bounds x="160" y="80" width="100" height="80" />
       </bpmndi:BPMNShape>
     </bpmndi:BPMNPlane>
diff --git a/test/spec/zeebe/Mappings.spec.js b/test/spec/zeebe/Mappings.spec.js
index 475f89e..9d88f81 100644
--- a/test/spec/zeebe/Mappings.spec.js
+++ b/test/spec/zeebe/Mappings.spec.js
@@ -13,6 +13,7 @@ import primitivesXML from 'test/fixtures/zeebe/mappings/primitives.bpmn';
 import mergingXML from 'test/fixtures/zeebe/mappings/merging.bpmn';
 import scopeXML from 'test/fixtures/zeebe/mappings/scope.bpmn';
 import scriptTaskXML from 'test/fixtures/zeebe/mappings/script-task.bpmn';
+import scriptTaskEmptyExpressionXML from 'test/fixtures/zeebe/mappings/script-task-empty-expression.bpmn';
 
 import VariableProvider from 'lib/VariableProvider';
 
@@ -320,30 +321,55 @@ describe('ZeebeVariableResolver - Variable Mappings', function() {
 
   describe('Script Task', function() {
 
-    beforeEach(bootstrap(scriptTaskXML));
+    describe('valid', function() {
 
+      beforeEach(bootstrap(scriptTaskXML));
 
-    it('should add type annotation for script tasks', inject(async function(variableResolver, elementRegistry) {
 
-      // given
-      const root = elementRegistry.get('Process_1');
+      it('should add type annotation for script tasks', inject(async function(variableResolver, elementRegistry) {
 
-      // when
-      const variables = await variableResolver.getVariablesForElement(root.businessObject);
+        // given
+        const element = elementRegistry.get('ScriptTask');
 
-      // then
-      expect(variables).to.variableEqual([
-        {
-          name: 'scriptResult',
-          type: 'Context',
-          info: '',
-          entries: [
-            { name: 'foo', type: 'Number', info: '123', entries: [] },
-          ]
-        }
-      ]);
-    }));
+        // when
+        const variables = await variableResolver.getVariablesForElement(element.businessObject);
+
+        // then
+        expect(variables).to.variableEqual([
+          {
+            name: 'scriptResult',
+            type: 'Context',
+            info: '',
+            entries: [
+              { name: 'foo', type: 'Number', info: '123', entries: [] },
+            ]
+          }
+        ]);
+      }));
+    });
+
+
+    describe('empty expression', function() {
 
+      beforeEach(bootstrap(scriptTaskEmptyExpressionXML));
+
+
+      it('should NOT error for empty expression', inject(async function(variableResolver, elementRegistry) {
+
+        // given
+        const element = elementRegistry.get('ScriptTask');
+
+        // when
+        const variables = await variableResolver.getVariablesForElement(element.businessObject);
+
+        // then
+        expect(variables).to.variableEqual([
+          {
+            name: 'scriptResult'
+          }
+        ]);
+      }));
+    });
   });
 
 });