[DROOLS-6961] NullPointerException in LambdaConsequence with global i…

drools-model/drools-model-compiler/src/main/java/org/drools/modelcompiler/consequence/LambdaConsequence.java

@@ -211,8 +211,9 @@ private Object[] initConsequence( KnowledgeHelper knowledgeHelper, InternalWorki
             tupleFactSupplier.resolveAndStore(facts, workingMemory, current.getFactHandle(), fhLookup);
         }
 
-        this.factSuppliers = factSuppliers.toArray( new TupleFactSupplier[factSuppliers.size()] );
+        // factSuppliers has to be last because factSuppliers is used as an initialization flag in fetchFacts(). See DROOLS-6961
         this.globalSuppliers = globalSuppliers.isEmpty() ? null : globalSuppliers.toArray( new GlobalSupplier[globalSuppliers.size()] );
+        this.factSuppliers = factSuppliers.toArray( new TupleFactSupplier[factSuppliers.size()] );
 
         if (!workingMemory.getSessionConfiguration().isThreadSafe()) {
             this.facts = facts;

drools-test-coverage/test-compiler-integration/src/test/java/org/drools/compiler/integrationtests/concurrency/GlobalConcurrencyTest.java

@@ -0,0 +1,142 @@
+/*
+ * Copyright 2022 Red Hat, Inc. and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ *
+ *      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.drools.compiler.integrationtests.concurrency;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import org.drools.testcoverage.common.model.Person;
+import org.drools.testcoverage.common.model.Result;
+import org.drools.testcoverage.common.util.KieBaseTestConfiguration;
+import org.drools.testcoverage.common.util.KieBaseUtil;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.kie.api.KieBase;
+import org.kie.api.runtime.KieSession;
+import org.kie.test.testcategory.TurtleTestCategory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@RunWith(Parameterized.class)
+@Category(TurtleTestCategory.class)
+public class GlobalConcurrencyTest {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(GlobalConcurrencyTest.class);
+
+    protected static int LOOP = 3000;
+    protected static int MAX_THREAD = 30;
+    protected final KieBaseTestConfiguration kieBaseTestConfiguration;
+
+    public GlobalConcurrencyTest(final KieBaseTestConfiguration kieBaseTestConfiguration) {
+        this.kieBaseTestConfiguration = kieBaseTestConfiguration;
+    }
+
+    @Parameterized.Parameters(name = "KieBase type={0}")
+    public static Collection<Object[]> getParameters() {
+        Collection<Object[]> parameters = new ArrayList<>();
+        parameters.add(new Object[]{KieBaseTestConfiguration.CLOUD_IDENTITY_MODEL_PATTERN}); // DROOLS-6961 : exec-model only
+        return parameters;
+    }
+
+    @Test
+    public void testGlobalConcurrency() {
+        String str =
+                "package org.mypkg;" +
+                     "import " + Person.class.getCanonicalName() + ";" +
+                     "import " + Result.class.getCanonicalName() + ";" +
+                     "global Result globalResult;" +
+                     "rule R1 when\n" +
+                     "  $p1 : Person(name == \"Mark\")\n" +
+                     "then\n" +
+                     "  globalResult.setValue($p1.getName() + \" is \" + $p1.getAge());\n" +
+                     "end\n" +
+                     "rule R2 when\n" +
+                     "  $p1 : Person(name == \"Edson\")\n" +
+                     "then\n" +
+                     "  globalResult.setValue($p1.getName() + \" is \" + $p1.getAge());\n" +
+                     "end";
+
+        List<Exception> exceptionList = new ArrayList<>();
+
+        for (int i = 0; i < LOOP; i++) {
+            if (i % 100 == 0) {
+                System.out.println("loop : " + i);
+            }
+
+            KieBase kieBase = KieBaseUtil.getKieBaseFromKieModuleFromDrl("global-test", kieBaseTestConfiguration, str);
+
+            ExecutorService executor = Executors.newFixedThreadPool(MAX_THREAD);
+            final CountDownLatch latch = new CountDownLatch(MAX_THREAD);
+            for (int n = 0; n < MAX_THREAD; n++) {
+                executor.execute(new Runnable() {
+
+                    public void run() {
+
+                        KieSession ksession = kieBase.newKieSession();
+                        Result result = new Result();
+                        ksession.setGlobal("globalResult", result);
+
+                        ksession.insert(new Person("Mark", 37));
+                        ksession.insert(new Person("Edson", 35));
+                        ksession.insert(new Person("Mario", 40));
+
+                        latch.countDown();
+                        try {
+                            latch.await();
+                        } catch (InterruptedException e) {
+                            LOGGER.error(e.getMessage(), e);
+                        }
+
+                        try {
+                            ksession.fireAllRules();
+                        } catch (Exception e) {
+                            exceptionList.add(e);
+                        }
+
+                        ksession.dispose();
+                    }
+                });
+            }
+
+            executor.shutdown();
+            try {
+                executor.awaitTermination(100, TimeUnit.SECONDS);
+            } catch (InterruptedException e) {
+                LOGGER.error(e.getMessage(), e);
+            }
+
+            if (!exceptionList.isEmpty()) {
+                break;
+            }
+        }
+
+        if (exceptionList.size() > 0) {
+            LOGGER.error(exceptionList.get(0).getMessage(), exceptionList.get(0));
+        }
+
+        assertThat(exceptionList).isEmpty();
+
+    }
+}