[kotlin] [bugfix] [maven-plugin]: prevent ClassCastException with boolean config options (#4361)

* fix: prevent classcast exception during execution of openapi-generator-maven-plugin.

* style: revert styling to openapi defaults

* test: unit test coverage for handling boolean config options

* fix: replace option value with boolean, if it is a string literal boolean

* style: use data type long

* test: add maven testfile kotlin.xml to travis build

* test: runnable maven test of the kotlin generator

.travis.yml

@@ -138,6 +138,7 @@ script:
   # test maven plugin
   - mvn clean compile -f modules/openapi-generator-maven-plugin/examples/java-client.xml
   - mvn clean compile -f modules/openapi-generator-maven-plugin/examples/multi-module/pom.xml
+  - mvn clean compile -f modules/openapi-generator-maven-plugin/examples/kotlin.xml
   # test gradle plugin
   - (cd modules/openapi-generator-gradle-plugin/samples/local-spec && ./gradlew buildGoSdk)
   - (cd modules/openapi-generator-gradle-plugin/samples/local-spec && ./gradlew openApiGenerate)

modules/openapi-generator-maven-plugin/examples/kotlin.xml

@@ -0,0 +1,237 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.openapitools</groupId>
+	<artifactId>sample-project</artifactId>
+	<packaging>jar</packaging>
+	<version>1.0-SNAPSHOT</version>
+	<name>sample-project</name>
+	<url>http://maven.apache.org</url>
+
+	<build>
+		<plugins>
+			<!-- activate the plugin -->
+			<plugin>
+				<groupId>org.openapitools</groupId>
+				<artifactId>openapi-generator-maven-plugin</artifactId>
+				<!-- RELEASE_VERSION -->
+				<version>4.2.1-SNAPSHOT</version>
+				<!-- /RELEASE_VERSION -->
+				<executions>
+					<execution>
+						<id>default</id>
+						<goals>
+							<goal>generate</goal>
+						</goals>
+						<configuration>
+							<!-- specify the swagger yaml -->
+							<inputSpec>${project.basedir}/swagger.yaml</inputSpec>
+
+							<!-- target to generate java client code -->
+							<generatorName>kotlin</generatorName>
+
+							<!-- hint: if you want to generate java server code, e.g. based on Spring Boot,
+								 you can use the following target: <generatorName>spring</generatorName> -->
+
+							<!-- pass any necessary config options -->
+							<configOptions>
+								<serializableModel>true</serializableModel>
+							</configOptions>
+
+						</configuration>
+					</execution>
+					<execution>
+						<id>kotlin</id>
+						<phase>generate-sources</phase>
+						<goals>
+							<goal>generate</goal>
+						</goals>
+						<configuration>
+							<!-- specify the swagger yaml -->
+							<inputSpec>https://raw.githubusercontent.com/OpenAPITools/openapi-generator/master/modules/openapi-generator/src/test/resources/2_0/petstore.yaml
+							</inputSpec>
+
+							<!-- target to generate java client code -->
+							<generatorName>kotlin</generatorName>
+
+							<!-- hint: if you want to generate java server code, e.g. based on Spring Boot,
+								 you can use the following target: <generatorName>spring</generatorName> -->
+
+							<!-- pass any necessary config options -->
+							<configOptions>
+								<serializableModel>true</serializableModel>
+							</configOptions>
+
+							<output>${project.build.directory}/generated-sources/kotlin</output>
+							<apiPackage>kotlintest.org.openapitools.client.api</apiPackage>
+							<modelPackage>kotlintest.org.openapitools.client.model</modelPackage>
+							<invokerPackage>kotlintest.org.openapitools.client</invokerPackage>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-compiler-plugin</artifactId>
+				<version>3.8.1</version>
+				<configuration>
+					<source>1.8</source>
+					<target>1.8</target>
+					<proc>none</proc>
+				</configuration>
+			</plugin>
+			<plugin>
+				<artifactId>kotlin-maven-plugin</artifactId>
+				<groupId>org.jetbrains.kotlin</groupId>
+				<configuration>
+					<jvmTarget>${kotlinJvmTarget}</jvmTarget>
+					<javacOptions/>
+				</configuration>
+				<executions>
+					<execution>
+						<id>compile</id>
+						<goals>
+							<goal>compile</goal>
+						</goals>
+						<configuration>
+							<sourceDirs>
+								<sourceDir>${project.build.directory}/generated-sources/kotlin/src/main/kotlin</sourceDir>
+							</sourceDirs>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+		<pluginManagement>
+			<plugins>
+				<plugin>
+					<artifactId>kotlin-maven-plugin</artifactId>
+					<groupId>org.jetbrains.kotlin</groupId>
+					<version>${kotlin.version}</version>
+				</plugin>
+			</plugins>
+		</pluginManagement>
+	</build>
+	<pluginRepositories>
+		<pluginRepository>
+			<id>sonatype-snapshots</id>
+			<url>https://oss.sonatype.org/content/repositories/snapshots/</url>
+		</pluginRepository>
+	</pluginRepositories>
+	<dependencies>
+		<!-- dependencies are needed for the client being generated -->
+
+		<dependency>
+			<groupId>io.swagger</groupId>
+			<artifactId>swagger-annotations</artifactId>
+			<version>${swagger-annotations-version}</version>
+		</dependency>
+
+		<!-- You can find the dependencies for the library configuation you chose by looking in JavaClientCodegen.
+			 Then find the corresponding dependency on Maven Central, and set the versions in the property section below -->
+
+		<!-- HTTP client: jersey-client -->
+		<dependency>
+			<groupId>org.glassfish.jersey.core</groupId>
+			<artifactId>jersey-client</artifactId>
+			<version>${jersey-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.glassfish.jersey.media</groupId>
+			<artifactId>jersey-media-multipart</artifactId>
+			<version>${jersey-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.glassfish.jersey.media</groupId>
+			<artifactId>jersey-media-json-jackson</artifactId>
+			<version>${jersey-version}</version>
+		</dependency>
+
+		<!-- @Nullable annotation -->
+		<dependency>
+			<groupId>com.google.code.findbugs</groupId>
+			<artifactId>jsr305</artifactId>
+			<version>3.0.2</version>
+		</dependency>
+
+		<!-- JSON processing: jackson -->
+		<dependency>
+			<groupId>com.fasterxml.jackson.jaxrs</groupId>
+			<artifactId>jackson-jaxrs-base</artifactId>
+			<version>${jackson-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.fasterxml.jackson.core</groupId>
+			<artifactId>jackson-core</artifactId>
+			<version>${jackson-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.fasterxml.jackson.core</groupId>
+			<artifactId>jackson-annotations</artifactId>
+			<version>${jackson-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.fasterxml.jackson.core</groupId>
+			<artifactId>jackson-databind</artifactId>
+			<version>${jackson-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.fasterxml.jackson.jaxrs</groupId>
+			<artifactId>jackson-jaxrs-json-provider</artifactId>
+			<version>${jackson-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.openapitools</groupId>
+			<artifactId>jackson-databind-nullable</artifactId>
+			<version>${jackson-databind-nullable-version}</version>
+		</dependency>
+
+		<!-- Joda time: if you use it -->
+		<dependency>
+			<groupId>com.fasterxml.jackson.datatype</groupId>
+			<artifactId>jackson-datatype-joda</artifactId>
+			<version>${jackson-version}</version>
+		</dependency>
+		<dependency>
+			<groupId>joda-time</groupId>
+			<artifactId>joda-time</artifactId>
+			<version>${jodatime-version}</version>
+		</dependency>
+
+		<!-- Base64 encoding that works in both JVM and Android -->
+		<dependency>
+			<groupId>com.brsanthu</groupId>
+			<artifactId>migbase64</artifactId>
+			<version>${migbase64.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.squareup.moshi</groupId>
+			<artifactId>moshi-kotlin</artifactId>
+			<version>${moshi-kotlin.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.squareup.moshi</groupId>
+			<artifactId>moshi-adapters</artifactId>
+			<version>${moshi-kotlin.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.squareup.okhttp3</groupId>
+			<artifactId>okhttp</artifactId>
+			<version>4.2.2</version>
+		</dependency>
+	</dependencies>
+
+	<properties>
+		<swagger-annotations-version>1.5.8</swagger-annotations-version>
+		<jersey-version>2.27</jersey-version>
+		<jackson-version>2.8.9</jackson-version>
+		<jackson-databind-nullable-version>0.2.0</jackson-databind-nullable-version>
+		<jodatime-version>2.7</jodatime-version>
+		<maven-plugin-version>1.0.0</maven-plugin-version>
+		<junit-version>4.8.1</junit-version>
+		<kotlin.version>1.3.50</kotlin.version>
+		<kotlinJvmTarget>1.8</kotlinJvmTarget>
+		<moshi-kotlin.version>1.8.0</moshi-kotlin.version>
+		<migbase64.version>2.2</migbase64.version>
+	</properties>
+</project>

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java

@@ -434,19 +434,19 @@ public abstract class AbstractKotlinCodegen extends DefaultCodegen implements Co
         }
 
         if (additionalProperties.containsKey(CodegenConstants.SERIALIZABLE_MODEL)) {
-            this.setSerializableModel(Boolean.valueOf((String) additionalProperties.get(CodegenConstants.SERIALIZABLE_MODEL)));
+            this.setSerializableModel(getBooleanOption(CodegenConstants.SERIALIZABLE_MODEL));
         } else {
             additionalProperties.put(CodegenConstants.SERIALIZABLE_MODEL, serializableModel);
         }
 
         if (additionalProperties.containsKey(CodegenConstants.PARCELIZE_MODELS)) {
-            this.setParcelizeModels(Boolean.valueOf((String) additionalProperties.get(CodegenConstants.PARCELIZE_MODELS)));
+            this.setParcelizeModels(getBooleanOption(CodegenConstants.PARCELIZE_MODELS));
         } else {
             additionalProperties.put(CodegenConstants.PARCELIZE_MODELS, parcelizeModels);
         }
 
         if (additionalProperties.containsKey(CodegenConstants.NON_PUBLIC_API)) {
-            this.setNonPublicApi(Boolean.valueOf((String) additionalProperties.get(CodegenConstants.NON_PUBLIC_API)));
+            this.setNonPublicApi(getBooleanOption(CodegenConstants.NON_PUBLIC_API));
         } else {
             additionalProperties.put(CodegenConstants.NON_PUBLIC_API, nonPublicApi);
         }
@@ -458,6 +458,18 @@ public abstract class AbstractKotlinCodegen extends DefaultCodegen implements Co
         additionalProperties.put("modelDocPath", modelDocPath);
     }
 
+    private boolean getBooleanOption(String key) {
+        final Object booleanValue = additionalProperties.get(key);
+        Boolean result = Boolean.FALSE;
+        if (booleanValue instanceof Boolean) {
+            result = (Boolean) booleanValue;
+        } else if (booleanValue instanceof String) {
+            result = Boolean.parseBoolean((String) booleanValue);
+        }
+        additionalProperties.put(key, result);
+        return result;
+    }
+
     public void setArtifactId(String artifactId) {
         this.artifactId = artifactId;
     }
@@ -501,7 +513,7 @@ public abstract class AbstractKotlinCodegen extends DefaultCodegen implements Co
     public void setSerializableModel(boolean serializableModel) {
         this.serializableModel = serializableModel;
     }
-    
+
     public boolean nonPublicApi() {
         return nonPublicApi;
     }

modules/openapi-generator/src/test/java/org/openapitools/codegen/kotlin/AbstractKotlinCodegenTest.java

@@ -1,5 +1,6 @@
 package org.openapitools.codegen.kotlin;
 
+import org.openapitools.codegen.CodegenConstants;
 import org.openapitools.codegen.CodegenType;
 import org.openapitools.codegen.languages.AbstractKotlinCodegen;
 import org.testng.Assert;
@@ -53,7 +54,7 @@ public class AbstractKotlinCodegenTest {
     }
 
     @Test
-    public void toEnumValue(){
+    public void toEnumValue() {
         assertEquals(codegen.toEnumValue("1", "kotlin.Int"), "1");
         assertEquals(codegen.toEnumValue("1", "kotlin.Double"), "1.0");
         assertEquals(codegen.toEnumValue("1.3", "kotlin.Double"), "1.3");
@@ -81,14 +82,14 @@ public class AbstractKotlinCodegenTest {
     }
 
     @Test
-    public void isDataTypeString(){
+    public void isDataTypeString() {
         assertFalse(codegen.isDataTypeString("kotlin.Int"));
         assertTrue(codegen.isDataTypeString("kotlin.String"));
         assertTrue(codegen.isDataTypeString("String"));
     }
 
     @Test
-    public void toModelNameShouldUseProvidedMapping()  {
+    public void toModelNameShouldUseProvidedMapping() {
         codegen.importMapping().put("json_myclass", "com.test.MyClass");
         assertEquals("com.test.MyClass", codegen.toModelName("json_myclass"));
     }
@@ -155,5 +156,45 @@ public class AbstractKotlinCodegenTest {
         Assert.assertEquals(codegen.apiTestFileFolder(), "/User/open/api/tools/test/folder/org/openapitools/codegen/api".replace('/', File.separatorChar));
     }
 
+    @Test
+    public void processOptsBooleanTrueFromString() {
+        codegen.additionalProperties().put(CodegenConstants.SERIALIZABLE_MODEL, "true");
+        codegen.processOpts();
+        Assert.assertTrue((boolean) codegen.additionalProperties().get(CodegenConstants.SERIALIZABLE_MODEL));
+    }
 
+    @Test
+    public void processOptsBooleanTrueFromBoolean() {
+        codegen.additionalProperties().put(CodegenConstants.SERIALIZABLE_MODEL, true);
+        codegen.processOpts();
+        Assert.assertTrue((boolean) codegen.additionalProperties().get(CodegenConstants.SERIALIZABLE_MODEL));
+    }
+
+    @Test
+    public void processOptsBooleanFalseFromString() {
+        codegen.additionalProperties().put(CodegenConstants.SERIALIZABLE_MODEL, "false");
+        codegen.processOpts();
+        Assert.assertFalse((boolean) codegen.additionalProperties().get(CodegenConstants.SERIALIZABLE_MODEL));
+    }
+
+    @Test
+    public void processOptsBooleanFalseFromBoolean() {
+        codegen.additionalProperties().put(CodegenConstants.SERIALIZABLE_MODEL, false);
+        codegen.processOpts();
+        Assert.assertFalse((boolean) codegen.additionalProperties().get(CodegenConstants.SERIALIZABLE_MODEL));
+    }
+
+    @Test
+    public void processOptsBooleanFalseFromGarbage() {
+        codegen.additionalProperties().put(CodegenConstants.SERIALIZABLE_MODEL, "blibb");
+        codegen.processOpts();
+        Assert.assertFalse((boolean) codegen.additionalProperties().get(CodegenConstants.SERIALIZABLE_MODEL));
+    }
+
+    @Test
+    public void processOptsBooleanFalseFromNumeric() {
+        codegen.additionalProperties().put(CodegenConstants.SERIALIZABLE_MODEL, 42L);
+        codegen.processOpts();
+        Assert.assertFalse((boolean) codegen.additionalProperties().get(CodegenConstants.SERIALIZABLE_MODEL));
+    }
 }