Add inheritVariables property to CMMN CaseTask and ProcessTask

modules/flowable-cmmn-converter/src/main/java/org/flowable/cmmn/converter/CaseTaskXmlConverter.java

@@ -44,6 +44,11 @@ protected CmmnElement convert(XMLStreamReader xtr, ConversionHelper conversionHe
             caseTask.setInheritBusinessKey(Boolean.parseBoolean(inheritBusinessKey));
         }
 
+        String inheritVariables = xtr.getAttributeValue(CmmnXmlConstants.FLOWABLE_EXTENSIONS_NAMESPACE, CmmnXmlConstants.ATTRIBUTE_INHERIT_VARIABLES);
+        if (inheritVariables != null) {
+            caseTask.setInheritVariables(Boolean.parseBoolean(inheritVariables));
+        }
+
         String fallbackToDefaultTenantValue = xtr.getAttributeValue(CmmnXmlConstants.FLOWABLE_EXTENSIONS_NAMESPACE, CmmnXmlConstants.ATTRIBUTE_FALLBACK_TO_DEFAULT_TENANT);
         if (fallbackToDefaultTenantValue != null) {
             caseTask.setFallbackToDefaultTenant(Boolean.valueOf(fallbackToDefaultTenantValue));

modules/flowable-cmmn-converter/src/main/java/org/flowable/cmmn/converter/CmmnXmlConstants.java

@@ -142,6 +142,7 @@ public interface CmmnXmlConstants {
     String ATTRIBUTE_FALLBACK_TO_DEFAULT_TENANT = "fallbackToDefaultTenant";
     String ATTRIBUTE_BUSINESS_KEY = "businessKey";
     String ATTRIBUTE_INHERIT_BUSINESS_KEY = "inheritBusinessKey";
+    String ATTRIBUTE_INHERIT_VARIABLES = "inheritVariables";
     String ATTRIBUTE_ID_VARIABLE_NAME = "idVariableName";
 
     String ELEMENT_CASE_REF_EXPRESSION = "caseRefExpression";

modules/flowable-cmmn-converter/src/main/java/org/flowable/cmmn/converter/ProcessTaskXmlConverter.java

@@ -44,6 +44,11 @@ protected CmmnElement convert(XMLStreamReader xtr, ConversionHelper conversionHe
             processTask.setInheritBusinessKey(Boolean.parseBoolean(inheritBusinessKey));
         }
 
+        String inheritVariables = xtr.getAttributeValue(CmmnXmlConstants.FLOWABLE_EXTENSIONS_NAMESPACE, CmmnXmlConstants.ATTRIBUTE_INHERIT_VARIABLES);
+        if (inheritVariables != null) {
+            processTask.setInheritVariables(Boolean.parseBoolean(inheritVariables));
+        }
+
         String fallbackToDefaultTenantValue = xtr.getAttributeValue(CmmnXmlConstants.FLOWABLE_EXTENSIONS_NAMESPACE, CmmnXmlConstants.ATTRIBUTE_FALLBACK_TO_DEFAULT_TENANT);
         if (fallbackToDefaultTenantValue != null) {
             processTask.setFallbackToDefaultTenant(Boolean.parseBoolean(fallbackToDefaultTenantValue));

modules/flowable-cmmn-converter/src/main/java/org/flowable/cmmn/converter/export/AbstractChildTaskExport.java

@@ -32,6 +32,9 @@ protected void writePlanItemDefinitionSpecificAttributes(T planItemDefinition, X
         if (planItemDefinition.isInheritBusinessKey()) {
             xtw.writeAttribute(FLOWABLE_EXTENSIONS_PREFIX, FLOWABLE_EXTENSIONS_NAMESPACE, ATTRIBUTE_INHERIT_BUSINESS_KEY, String.valueOf(planItemDefinition.isInheritBusinessKey()));
         }
+        if (planItemDefinition.isInheritVariables()) {
+            xtw.writeAttribute(FLOWABLE_EXTENSIONS_PREFIX, FLOWABLE_EXTENSIONS_NAMESPACE, ATTRIBUTE_INHERIT_VARIABLES, String.valueOf(planItemDefinition.isInheritVariables()));
+        }
     }
 
     @Override

modules/flowable-cmmn-converter/src/test/java/org/flowable/test/cmmn/converter/CaseTaskCmmnXmlConverterTest.java

@@ -52,6 +52,7 @@ public void validateModel(CmmnModel cmmnModel) {
                     assertThat(task1.getCaseRefExpression()).isEqualTo("caseDefinitionKey");
                     assertThat(task1.getFallbackToDefaultTenant()).isTrue();
                     assertThat(task1.isSameDeployment()).isTrue();
+                    assertThat(task1.isInheritVariables()).isTrue();
 
                     assertThat(task1.getInParameters())
                             .extracting(IOParameter::getSource, IOParameter::getTarget)

modules/flowable-cmmn-converter/src/test/java/org/flowable/test/cmmn/converter/ProcessTask2CmmnXmlConverterTest.java

@@ -49,6 +49,7 @@ public void validateModel(CmmnModel cmmnModel) {
                 .isInstanceOfSatisfying(ProcessTask.class, task1 -> {
                     assertThat(task1.getProcessRefExpression()).isEqualTo("myTestProcess");
                     assertThat((task1.isSameDeployment())).isTrue();
+                    assertThat(task1.isInheritVariables()).isTrue();
 
                     assertThat(task1.getInParameters()).isEmpty();
                     assertThat(task1.getOutParameters()).isEmpty();

modules/flowable-cmmn-converter/src/test/resources/org/flowable/test/cmmn/converter/case-task.cmmn

@@ -21,7 +21,7 @@
             </sentry>
 
             <task id="theTask" name="The Task" isBlocking="true" />
-            <caseTask id="theCase" isBlocking="true" flowable:fallbackToDefaultTenant="true" flowable:sameDeployment="true">
+            <caseTask id="theCase" isBlocking="true" flowable:fallbackToDefaultTenant="true" flowable:sameDeployment="true" flowable:inheritVariables="true">
                 <extensionElements>
                     <flowable:in source="testSource" target="testTarget"></flowable:in>
                 </extensionElements>

modules/flowable-cmmn-converter/src/test/resources/org/flowable/test/cmmn/converter/process-task2.cmmn

@@ -17,7 +17,7 @@
           <modeler:initiator-can-complete xmlns:modeler="http://flowable.org/modeler"><![CDATA[false]]></modeler:initiator-can-complete>
         </extensionElements>
       </humanTask>
-      <processTask id="oneprocesstask1" name="Process task" flowable:sameDeployment="true">
+      <processTask id="oneprocesstask1" name="Process task" flowable:sameDeployment="true" flowable:inheritVariables="true">
         <processRefExpression><![CDATA[myTestProcess]]></processRefExpression>
       </processTask>
     </casePlanModel>

modules/flowable-cmmn-engine-configurator/src/test/java/org/flowable/cmmn/test/ProcessTaskTest.java

@@ -1015,6 +1015,33 @@ public void testIOParameterCombinations() {
                 .hasSize(4 + 4); // 4 from in mapping, 4 from task complete
     }
 
+    @Test
+    @CmmnDeployment
+    @org.flowable.engine.test.Deployment(resources = "org/flowable/cmmn/test/oneTaskProcess.bpmn20.xml")
+    public void testProcessTaskInheritVariables() {
+        CaseInstance caseInstance = cmmnRuntimeService.createCaseInstanceBuilder()
+                .caseDefinitionKey("myCase")
+                .variable("caseVariableA", "hello")
+                .variable("caseVariableB", "world")
+                .variable("caseVariableC", 42)
+                .start();
+
+        PlanItemInstance processTaskPlanItemInstance = cmmnRuntimeService.createPlanItemInstanceQuery()
+                .caseInstanceId(caseInstance.getId())
+                .planItemDefinitionType(PlanItemDefinitionType.PROCESS_TASK)
+                .singleResult();
+        String processInstanceId = processTaskPlanItemInstance.getReferenceId();
+        ProcessInstance processInstance = processEngineRuntimeService.createProcessInstanceQuery().processInstanceId(processInstanceId).singleResult();
+        assertThat(processInstance).isNotNull();
+
+        // All case variables are inherited into the child process instance (like a BPMN call activity)
+        assertThat(processEngineRuntimeService.getVariable(processInstanceId, "caseVariableA")).isEqualTo("hello");
+        assertThat(processEngineRuntimeService.getVariable(processInstanceId, "caseVariableC")).isEqualTo(42);
+
+        // An explicit in parameter takes precedence over the inherited variable
+        assertThat(processEngineRuntimeService.getVariable(processInstanceId, "caseVariableB")).isEqualTo("overridden");
+    }
+
     @Test
     @CmmnDeployment
     public void testProcessTaskWithSkipExpressions() {

modules/flowable-cmmn-engine-configurator/src/test/resources/org/flowable/cmmn/test/ProcessTaskTest.testProcessTaskInheritVariables.cmmn

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<definitions xmlns="http://www.omg.org/spec/CMMN/20151109/MODEL"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns:flowable="http://flowable.org/cmmn"
+    targetNamespace="http://flowable.org/cmmn">
+
+    <case id="myCase">
+        <casePlanModel id="myPlanModel" name="My CasePlanModel">
+            <planItem id="planItem1" name="The Process" definitionRef="theProcess" />
+            <processTask id="theProcess" isBlocking="true" flowable:inheritVariables="true">
+                <extensionElements>
+                    <flowable:in sourceExpression="${'overridden'}" target="caseVariableB" />
+                </extensionElements>
+                <processRefExpression><![CDATA[oneTask]]></processRefExpression>
+            </processTask>
+        </casePlanModel>
+    </case>
+
+</definitions>

modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/behavior/impl/CaseTaskActivityBehavior.java

@@ -57,7 +57,8 @@ public class CaseTaskActivityBehavior extends ChildTaskActivityBehavior implemen
     protected CaseTask caseTask;
 
     public CaseTaskActivityBehavior(Expression caseRefExpression, CaseTask caseTask) {
-        super(caseTask.isBlocking(), caseTask.getBlockingExpression(), caseTask.getInParameters(), caseTask.getOutParameters());
+        super(caseTask.isBlocking(), caseTask.getBlockingExpression(), caseTask.getInParameters(), caseTask.getOutParameters(),
+                caseTask.isInheritVariables());
         this.caseRefExpression = caseRefExpression;
         this.caseRef = caseTask.getCaseRef();
         this.fallbackToDefaultTenant = caseTask.getFallbackToDefaultTenant();

modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/behavior/impl/ChildTaskActivityBehavior.java

@@ -43,16 +43,23 @@ public abstract class ChildTaskActivityBehavior extends CoreCmmnTriggerableActiv
     protected String isBlockingExpression;
     protected List<IOParameter> inParameters;
     protected List<IOParameter> outParameters;
+    protected boolean inheritVariables;
 
     public ChildTaskActivityBehavior(boolean isBlocking, String isBlockingExpression) {
         this.isBlocking = isBlocking;
         this.isBlockingExpression = isBlockingExpression;
     }
 
     public ChildTaskActivityBehavior(boolean isBlocking, String isBlockingExpression, List<IOParameter> inParameters, List<IOParameter> outParameters) {
+        this(isBlocking, isBlockingExpression, inParameters, outParameters, false);
+    }
+
+    public ChildTaskActivityBehavior(boolean isBlocking, String isBlockingExpression, List<IOParameter> inParameters, List<IOParameter> outParameters,
+            boolean inheritVariables) {
         this(isBlocking, isBlockingExpression);
         this.inParameters = inParameters;
         this.outParameters = outParameters;
+        this.inheritVariables = inheritVariables;
     }
 
     @Override
@@ -83,6 +90,12 @@ protected void handleInParameters(PlanItemInstanceEntity planItemInstanceEntity,
                                       CmmnEngineConfiguration cmmnEngineConfiguration, Map<String, Object> inParametersMap,
                                       ExpressionManager expressionManager) {
 
+        if (inheritVariables) {
+            // Inherit all variables from the parent. Explicit in parameters are
+            // applied afterwards, so they take precedence over the inherited variables.
+            inParametersMap.putAll(planItemInstanceEntity.getVariables());
+        }
+
         IOParameterUtil.processInParameters(inParameters, planItemInstanceEntity, inParametersMap, expressionManager);
     }
 

modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/behavior/impl/ProcessTaskActivityBehavior.java

@@ -57,7 +57,8 @@ public class ProcessTaskActivityBehavior extends ChildTaskActivityBehavior imple
     protected ProcessTask processTask;
 
     public ProcessTaskActivityBehavior(Process process, Expression processRefExpression, ProcessTask processTask) {
-        super(processTask.isBlocking(), processTask.getBlockingExpression(), processTask.getInParameters(), processTask.getOutParameters());
+        super(processTask.isBlocking(), processTask.getBlockingExpression(), processTask.getInParameters(), processTask.getOutParameters(),
+                processTask.isInheritVariables());
         this.process = process;
         this.processRefExpression = processRefExpression;
         this.processRef = processTask.getProcessRef();

modules/flowable-cmmn-engine/src/test/java/org/flowable/cmmn/test/runtime/CaseTaskTest.java

@@ -1236,6 +1236,32 @@ public void testWithInheritBusinessKeyButWithoutBusinessKey() {
         cmmnRuntimeService.triggerPlanItemInstance(planItemInstance.getId());
     }
 
+    @Test
+    @CmmnDeployment(resources = {
+            "org/flowable/cmmn/test/runtime/CaseTaskTest.testCaseTaskInheritVariables.cmmn",
+            "org/flowable/cmmn/test/runtime/oneTaskCase.cmmn"
+    })
+    public void testCaseTaskInheritVariables() {
+        CaseInstance caseInstance = cmmnRuntimeService.createCaseInstanceBuilder()
+                .caseDefinitionKey("myCase")
+                .variable("caseVariableA", "hello")
+                .variable("caseVariableB", "world")
+                .variable("caseVariableC", 42)
+                .start();
+
+        CaseInstance subCase = cmmnRuntimeService.createCaseInstanceQuery()
+                .caseDefinitionKey("oneTaskCase")
+                .singleResult();
+        assertThat(subCase).isNotNull();
+
+        // All parent case variables are inherited into the child case instance (like a BPMN call activity)
+        assertThat(cmmnRuntimeService.getVariable(subCase.getId(), "caseVariableA")).isEqualTo("hello");
+        assertThat(cmmnRuntimeService.getVariable(subCase.getId(), "caseVariableC")).isEqualTo(42);
+
+        // An explicit in parameter takes precedence over the inherited variable
+        assertThat(cmmnRuntimeService.getVariable(subCase.getId(), "caseVariableB")).isEqualTo("overridden");
+    }
+
     @Test
     @CmmnDeployment
     public void testIdVariableName() {

modules/flowable-cmmn-engine/src/test/resources/org/flowable/cmmn/test/runtime/CaseTaskTest.testCaseTaskInheritVariables.cmmn

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<definitions xmlns="http://www.omg.org/spec/CMMN/20151109/MODEL"
+             xmlns:flowable="http://flowable.org/cmmn"
+             targetNamespace="http://flowable.org/cmmn">
+
+    <case id="myCase">
+        <casePlanModel id="myPlanModel" name="My CasePlanModel">
+            <planItem id="planItem1" name="The Case" definitionRef="theCase"/>
+            <caseTask id="theCase" caseRef="oneTaskCase" isBlocking="true" flowable:inheritVariables="true">
+                <extensionElements>
+                    <flowable:in sourceExpression="${'overridden'}" target="caseVariableB"/>
+                </extensionElements>
+            </caseTask>
+        </casePlanModel>
+    </case>
+</definitions>

modules/flowable-cmmn-model/src/main/java/org/flowable/cmmn/model/ChildTask.java

@@ -22,6 +22,7 @@ public class ChildTask extends Task implements HasInParameters, HasOutParameters
 
     protected String businessKey;
     protected boolean inheritBusinessKey;
+    protected boolean inheritVariables;
     protected List<IOParameter> inParameters = new ArrayList<>();
     protected List<IOParameter> outParameters = new ArrayList<>();
 
@@ -41,6 +42,14 @@ public void setInheritBusinessKey(boolean inheritBusinessKey) {
         this.inheritBusinessKey = inheritBusinessKey;
     }
 
+    public boolean isInheritVariables() {
+        return inheritVariables;
+    }
+
+    public void setInheritVariables(boolean inheritVariables) {
+        this.inheritVariables = inheritVariables;
+    }
+
     @Override
     public List<IOParameter> getInParameters() {
         return inParameters;