[DROOLS-7518] NullPointerException in MemoryFileSystem when kbase.nam…

…e is empty in kmodule.xml (apache#5414)

drools-compiler/src/main/java/org/drools/compiler/kproject/KieModuleException.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2023 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.
+ * 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.drools.compiler.kproject;
+
+public class KieModuleException extends RuntimeException {
+
+    public KieModuleException(String message) {
+        super(message);
+    }
+}

drools-compiler/src/main/java/org/drools/compiler/kproject/models/KieBaseModelImpl.java

@@ -30,6 +30,7 @@
 import com.thoughtworks.xstream.converters.UnmarshallingContext;
 import com.thoughtworks.xstream.io.HierarchicalStreamReader;
 import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
+import org.drools.compiler.kproject.KieModuleException;
 import org.drools.core.util.AbstractXStreamConverter;
 import org.drools.core.util.StringUtils;
 import org.kie.api.builder.model.KieBaseModel;
@@ -432,6 +433,9 @@ public Object unmarshal(HierarchicalStreamReader reader,
 
             String kbaseName = reader.getAttribute( "name" );
             kBase.name = kbaseName != null ? kbaseName : StringUtils.uuid();
+            if (kBase.name.isEmpty()) {
+                throw new KieModuleException("kbase name is empty in kmodule.xml");
+            }
 
             kBase.setDefault( "true".equals(reader.getAttribute( "default" )) );
 

drools-compiler/src/main/java/org/drools/compiler/kproject/models/KieSessionModelImpl.java

@@ -25,6 +25,7 @@
 import com.thoughtworks.xstream.converters.UnmarshallingContext;
 import com.thoughtworks.xstream.io.HierarchicalStreamReader;
 import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
+import org.drools.compiler.kproject.KieModuleException;
 import org.drools.core.BeliefSystemType;
 import org.drools.core.util.AbstractXStreamConverter;
 import org.kie.api.builder.model.ChannelModel;
@@ -340,6 +341,9 @@ public void marshal(Object value, HierarchicalStreamWriter writer, MarshallingCo
         public Object unmarshal(HierarchicalStreamReader reader, final UnmarshallingContext context) {
             final KieSessionModelImpl kSession = new KieSessionModelImpl();
             kSession.name = reader.getAttribute("name");
+            if (kSession.name.isEmpty()) {
+                throw new KieModuleException("ksession name is empty in kmodule.xml");
+            }
             kSession.setDefault( "true".equals(reader.getAttribute( "default" )) );
             kSession.setDirectFiring( "true".equals(reader.getAttribute( "directFiring" )) );
             kSession.setThreadSafe( "true".equals(reader.getAttribute( "threadSafe" )) );

drools-test-coverage/test-compiler-integration/src/test/java/org/drools/mvel/integrationtests/KmoduleXmlTest.java

@@ -0,0 +1,121 @@
+/*
+ * Copyright 2023 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.mvel.integrationtests;
+
+import java.util.Collection;
+import java.util.List;
+
+import org.drools.testcoverage.common.util.KieBaseTestConfiguration;
+import org.drools.testcoverage.common.util.KieUtil;
+import org.drools.testcoverage.common.util.TestParametersUtil;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.kie.api.KieServices;
+import org.kie.api.builder.KieBuilder;
+import org.kie.api.builder.KieFileSystem;
+import org.kie.api.builder.Message;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@RunWith(Parameterized.class)
+public class KmoduleXmlTest {
+
+    enum Element {
+        KBASE,
+        KSESSION
+    }
+
+    private final KieBaseTestConfiguration kieBaseTestConfiguration;
+
+    public KmoduleXmlTest(final KieBaseTestConfiguration kieBaseTestConfiguration) {
+        this.kieBaseTestConfiguration = kieBaseTestConfiguration;
+    }
+
+    @Parameterized.Parameters(name = "KieBase type={0}")
+    public static Collection<Object[]> getParameters() {
+        return TestParametersUtil.getKieBaseCloudConfigurations(true);
+    }
+
+    @Test
+    public void kbaseEmptyName() throws Exception {
+        List<Message> errors = buildKmoduleWithEmptyValue("name", Element.KBASE);
+
+        assertThat(errors).isNotEmpty();
+        assertThat(errors.get(0).getText()).contains("kbase name is empty in kmodule.xml");
+    }
+
+    @Test
+    public void kbaseEmptyIncludes() throws Exception {
+        List<Message> errors = buildKmoduleWithEmptyValue("includes", Element.KBASE);
+
+        assertThat(errors).as("Empty includes is fine. It's ignored")
+                          .isEmpty();
+    }
+
+    @Test
+    public void kbaseEmptyPackages() throws Exception {
+        List<Message> errors = buildKmoduleWithEmptyValue("packages", Element.KBASE);
+
+        assertThat(errors).as("Empty packages is fine. It means the default package")
+                          .isEmpty();
+    }
+
+    @Test
+    public void ksessionEmptyName() throws Exception {
+        List<Message> errors = buildKmoduleWithEmptyValue("name", Element.KSESSION);
+
+        assertThat(errors).isNotEmpty();
+        assertThat(errors.get(0).getText()).contains("ksession name is empty in kmodule.xml");
+    }
+
+    private List<Message> buildKmoduleWithEmptyValue(String emptyAttribute, Element element) throws Exception {
+        String drl =
+                "package org.example\n" +
+                     "rule R1 when\n" +
+                     "then\n" +
+                     "end\n";
+
+        KieServices ks = KieServices.Factory.get();
+
+        KieFileSystem kfs = ks.newKieFileSystem();
+        kfs.write("src/main/resources/org/example/r1.drl", drl);
+        kfs.write("src/main/resources/META-INF/kmodule.xml", getKmoduleString(emptyAttribute, element));
+        final KieBuilder kieBuilder = KieUtil.getKieBuilderFromKieFileSystem(kieBaseTestConfiguration, kfs, false);
+
+        return kieBuilder.getResults().getMessages(Message.Level.ERROR);
+    }
+
+    private String getKmoduleString(String emptyAttribute, Element element) {
+        StringBuilder sb = new StringBuilder();
+        sb.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
+        sb.append("<kmodule xmlns=\"http://www.drools.org/xsd/kmodule\" xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\">\n");
+        if (element == Element.KBASE) {
+            // if kbase name is omitted, UUID is given to its name
+            sb.append("<kbase " + emptyAttribute + "=\"\" default=\"true\">\n");
+            sb.append("  <ksession name=\"myKsession\" default=\"true\"/>\n");
+        } else if (element == Element.KSESSION) {
+            sb.append("<kbase name=\"myKbase\" default=\"true\">\n");
+            // if you test an attribute other than "name" in ksession, you need to add "name" attribute as it's required
+            sb.append("  <ksession " + emptyAttribute + "=\"\" default=\"true\"/>\n");
+        } else {
+            throw new IllegalArgumentException("Unsupported element : " + element);
+        }
+        sb.append("</kbase>\n");
+        sb.append("</kmodule>\n");
+        return sb.toString();
+    }
+}