From acb7a5def353d52f634dda59917c0e00b06244ec Mon Sep 17 00:00:00 2001
From: Arthur H <516104+arthware@users.noreply.github.com>
Date: Wed, 14 Jun 2023 08:30:01 +0200
Subject: [PATCH] Fix VariableContainerELResolver to return a value for plain
 VariableContainers (#3662)

* The VariableContainerElResolver missed an else branch to return a value for plain VariableContainers (Handled VariableScope only).
---
 .../impl/el/VariableContainerELResolver.java  |  4 +
 .../JsonVariableContainerExpressionTest.java  | 76 +++++++++++++++++++
 2 files changed, 80 insertions(+)
 create mode 100644 modules/flowable-engine/src/test/java/org/flowable/engine/test/el/JsonVariableContainerExpressionTest.java

diff --git a/modules/flowable-engine-common/src/main/java/org/flowable/common/engine/impl/el/VariableContainerELResolver.java b/modules/flowable-engine-common/src/main/java/org/flowable/common/engine/impl/el/VariableContainerELResolver.java
index 2de1515bba8..142182854f7 100644
--- a/modules/flowable-engine-common/src/main/java/org/flowable/common/engine/impl/el/VariableContainerELResolver.java
+++ b/modules/flowable-engine-common/src/main/java/org/flowable/common/engine/impl/el/VariableContainerELResolver.java
@@ -50,6 +50,10 @@ public Object getValue(ELContext context, Object base, Object property) {
                             // reviews[0].score, reviews is an aggregated variable which is read only
                             value = variableInstance.getValue();
                         }
+                    } else {
+                        // simple variable container can be written to by default.
+                        // No further checks required.
+                        value = variableContainer.getVariable(variable);
                     }
                 } else {
                     value = variableContainer.getVariable(variable);
diff --git a/modules/flowable-engine/src/test/java/org/flowable/engine/test/el/JsonVariableContainerExpressionTest.java b/modules/flowable-engine/src/test/java/org/flowable/engine/test/el/JsonVariableContainerExpressionTest.java
new file mode 100644
index 00000000000..3bf01034b81
--- /dev/null
+++ b/modules/flowable-engine/src/test/java/org/flowable/engine/test/el/JsonVariableContainerExpressionTest.java
@@ -0,0 +1,76 @@
+/* Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.flowable.engine.test.el;
+
+import static net.javacrumbs.jsonunit.assertj.JsonAssertions.assertThatJson;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.flowable.common.engine.api.variable.VariableContainer;
+import org.flowable.common.engine.impl.el.VariableContainerWrapper;
+import org.flowable.common.engine.impl.variable.MapDelegateVariableContainer;
+import org.flowable.engine.impl.test.PluggableFlowableTestCase;
+import org.junit.jupiter.api.Test;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+
+public class JsonVariableContainerExpressionTest extends PluggableFlowableTestCase {
+
+    @Test
+    public void setNestedJsonVariableValueWithVariableContainerWrapper() {
+
+        ObjectMapper objectMapper = new ObjectMapper();
+        ObjectNode objectNode = objectMapper.createObjectNode();
+
+        Map<String, Object> variables = new HashMap<>();
+        variables.put("muppetshow", objectNode);
+
+        VariableContainerWrapper simpleVariableContainer = new VariableContainerWrapper(variables);
+        assertThatJson(executeSetValueExpression("${muppetshow.characters.frog.name}", "Kermit", simpleVariableContainer)
+                .getVariable("muppetshow"))
+                .isEqualTo("{characters:{frog:{'name':'Kermit'}}}");
+
+        assertThatJson(executeSetValueExpression("${muppetshow.startingYear}", 1976, simpleVariableContainer)
+                .getVariable("muppetshow"))
+                .isEqualTo("{characters:{frog:{name:'Kermit'}},startingYear:1976}");
+    }
+
+    @Test
+    public void setNestedJsonVariableValueWithMapDelegateVariableContainer() {
+
+        ObjectMapper objectMapper = new ObjectMapper();
+        ObjectNode objectNode = objectMapper.createObjectNode();
+        MapDelegateVariableContainer simpleVariableContainer = new MapDelegateVariableContainer().addTransientVariable("muppetshow", objectNode);
+        assertThatJson(executeSetValueExpression("${muppetshow.characters.frog.name}", "Kermit", simpleVariableContainer)
+                .getVariable("muppetshow"))
+                .isEqualTo("{characters:{frog:{'name':'Kermit'}}}");
+
+        assertThatJson(executeSetValueExpression("${muppetshow.startingYear}", 1976, simpleVariableContainer)
+                .getVariable("muppetshow"))
+                .isEqualTo("{characters:{frog:{name:'Kermit'}},startingYear:1976}");
+    }
+
+    protected VariableContainer executeSetValueExpression(String expression, Object value, VariableContainer variableContainer) {
+        processEngineConfiguration.getCommandExecutor()
+                .execute(commandContext -> {
+                    processEngineConfiguration.getExpressionManager()
+                            .createExpression(expression)
+                            .setValue(value, variableContainer);
+                    return null;
+                });
+        return variableContainer;
+    }
+
+}