Enable strict null-safety for Kotlin projects

Closes gh-591

initializr-generator/src/main/resources/templates/starter-build.gradle

@@ -46,13 +46,15 @@ apply plugin: 'war'
 
 group = '{{groupId}}'
 version = '{{version}}'
-sourceCompatibility = {{javaVersion}}{{#kotlin}}{{#java8OrLater}}
+sourceCompatibility = {{javaVersion}}{{#kotlin}}
 compileKotlin {
-	kotlinOptions.jvmTarget = "1.8"
+	freeCompilerArgs = ["-Xjsr305=strict"]{{#java8OrLater}}
+	kotlinOptions.jvmTarget = "1.8"{{/java8OrLater}}
 }
 compileTestKotlin {
-	kotlinOptions.jvmTarget = "1.8"
+	freeCompilerArgs = ["-Xjsr305=strict"]{{#java8OrLater}}
-}{{/java8OrLater}}{{/kotlin}}
+	kotlinOptions.jvmTarget = "1.8"{{/java8OrLater}}
+}{{/kotlin}}
 
 repositories {
 	mavenCentral()

initializr-generator/src/main/resources/templates/starter-pom.xml

@@ -177,6 +177,9 @@
 				<version>${kotlin.version}</version>
 				{{/kotlinSupport}}
 				<configuration>
+					<args>
+						<arg>-Xjsr305=strict</arg>
+					</args>
 					<compilerPlugins>
 						<plugin>spring</plugin>
 					</compilerPlugins>

initializr-generator/src/test/resources/project/gradle/kotlin-java6-build.gradle.gen

@@ -23,6 +23,12 @@ apply plugin: 'io.spring.dependency-management'
 group = 'com.example'
 version = '0.0.1-SNAPSHOT'
 sourceCompatibility = 1.6
+compileKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
+}
+compileTestKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
+}
 
 repositories {
 	mavenCentral()

initializr-generator/src/test/resources/project/gradle/kotlin-java7-build.gradle.gen

@@ -23,6 +23,12 @@ apply plugin: 'io.spring.dependency-management'
 group = 'com.example'
 version = '0.0.1-SNAPSHOT'
 sourceCompatibility = 1.7
+compileKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
+}
+compileTestKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
+}
 
 repositories {
 	mavenCentral()

initializr-generator/src/test/resources/project/gradle/kotlin-java9-build.gradle.gen

@@ -25,9 +25,11 @@ group = 'com.example'
 version = '0.0.1-SNAPSHOT'
 sourceCompatibility = 9
 compileKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
 	kotlinOptions.jvmTarget = "1.8"
 }
 compileTestKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
 	kotlinOptions.jvmTarget = "1.8"
 }
 

initializr-generator/src/test/resources/project/gradle/kotlin-springboot2-build.gradle.gen

@@ -25,9 +25,11 @@ group = 'com.example'
 version = '0.0.1-SNAPSHOT'
 sourceCompatibility = 1.8
 compileKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
 	kotlinOptions.jvmTarget = "1.8"
 }
 compileTestKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
 	kotlinOptions.jvmTarget = "1.8"
 }
 

initializr-generator/src/test/resources/project/gradle/kotlin-springboot2-legacy-build.gradle.gen

@@ -25,9 +25,11 @@ group = 'com.example'
 version = '0.0.1-SNAPSHOT'
 sourceCompatibility = 1.8
 compileKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
 	kotlinOptions.jvmTarget = "1.8"
 }
 compileTestKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
 	kotlinOptions.jvmTarget = "1.8"
 }
 

initializr-generator/src/test/resources/project/kotlin/standard/build.gradle.gen

@@ -24,9 +24,11 @@ group = 'com.example'
 version = '0.0.1-SNAPSHOT'
 sourceCompatibility = 1.8
 compileKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
 	kotlinOptions.jvmTarget = "1.8"
 }
 compileTestKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
 	kotlinOptions.jvmTarget = "1.8"
 }
 

initializr-generator/src/test/resources/project/kotlin/standard/pom.xml.gen

@@ -61,6 +61,9 @@
 				<groupId>org.jetbrains.kotlin</groupId>
 				<version>${kotlin.version}</version>
 				<configuration>
+					<args>
+						<arg>-Xjsr305=strict</arg>
+					</args>
 					<compilerPlugins>
 						<plugin>spring</plugin>
 					</compilerPlugins>

initializr-generator/src/test/resources/project/kotlin/war/build.gradle.gen

@@ -25,9 +25,11 @@ group = 'com.example'
 version = '0.0.1-SNAPSHOT'
 sourceCompatibility = 1.8
 compileKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
 	kotlinOptions.jvmTarget = "1.8"
 }
 compileTestKotlin {
+	freeCompilerArgs = ["-Xjsr305=strict"]
 	kotlinOptions.jvmTarget = "1.8"
 }
 

initializr-generator/src/test/resources/project/kotlin/war/pom.xml.gen

@@ -66,6 +66,9 @@
 				<groupId>org.jetbrains.kotlin</groupId>
 				<version>${kotlin.version}</version>
 				<configuration>
+					<args>
+						<arg>-Xjsr305=strict</arg>
+					</args>
 					<compilerPlugins>
 						<plugin>spring</plugin>
 					</compilerPlugins>

initializr-generator/src/test/resources/project/maven/kotlin-java6-pom.xml.gen

@@ -61,6 +61,9 @@
 				<groupId>org.jetbrains.kotlin</groupId>
 				<version>${kotlin.version}</version>
 				<configuration>
+					<args>
+						<arg>-Xjsr305=strict</arg>
+					</args>
 					<compilerPlugins>
 						<plugin>spring</plugin>
 					</compilerPlugins>

initializr-generator/src/test/resources/project/maven/kotlin-java7-pom.xml.gen

@@ -61,6 +61,9 @@
 				<groupId>org.jetbrains.kotlin</groupId>
 				<version>${kotlin.version}</version>
 				<configuration>
+					<args>
+						<arg>-Xjsr305=strict</arg>
+					</args>
 					<compilerPlugins>
 						<plugin>spring</plugin>
 					</compilerPlugins>

initializr-generator/src/test/resources/project/maven/kotlin-java9-pom.xml.gen

@@ -58,6 +58,9 @@
 				<artifactId>kotlin-maven-plugin</artifactId>
 				<groupId>org.jetbrains.kotlin</groupId>
 				<configuration>
+					<args>
+						<arg>-Xjsr305=strict</arg>
+					</args>
 					<compilerPlugins>
 						<plugin>spring</plugin>
 					</compilerPlugins>

initializr-generator/src/test/resources/project/maven/kotlin-springboot2-legacy-pom.xml.gen

@@ -61,6 +61,9 @@
 				<groupId>org.jetbrains.kotlin</groupId>
 				<version>${kotlin.version}</version>
 				<configuration>
+					<args>
+						<arg>-Xjsr305=strict</arg>
+					</args>
 					<compilerPlugins>
 						<plugin>spring</plugin>
 					</compilerPlugins>

initializr-generator/src/test/resources/project/maven/kotlin-springboot2-pom.xml.gen

@@ -58,6 +58,9 @@
 				<artifactId>kotlin-maven-plugin</artifactId>
 				<groupId>org.jetbrains.kotlin</groupId>
 				<configuration>
+					<args>
+						<arg>-Xjsr305=strict</arg>
+					</args>
 					<compilerPlugins>
 						<plugin>spring</plugin>
 					</compilerPlugins>