Add .kotlin directory to .gitignore if Gradle is used

Closes gh-1501

Author: mhalbritter

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/code/kotlin/KotlinProjectGenerationConfiguration.java

@@ -16,6 +16,8 @@
 
 package io.spring.initializr.generator.spring.code.kotlin;
 
+import io.spring.initializr.generator.buildsystem.gradle.GradleBuildSystem;
+import io.spring.initializr.generator.condition.ConditionalOnBuildSystem;
 import io.spring.initializr.generator.condition.ConditionalOnLanguage;
 import io.spring.initializr.generator.io.IndentingWriterFactory;
 import io.spring.initializr.generator.language.kotlin.KotlinCompilationUnit;
@@ -32,6 +34,8 @@
 import io.spring.initializr.generator.spring.code.TestApplicationTypeCustomizer;
 import io.spring.initializr.generator.spring.code.TestSourceCodeCustomizer;
 import io.spring.initializr.generator.spring.code.TestSourceCodeProjectContributor;
+import io.spring.initializr.generator.spring.scm.git.GitIgnore;
+import io.spring.initializr.generator.spring.scm.git.GitIgnoreCustomizer;
 import io.spring.initializr.metadata.InitializrMetadata;
 
 import org.springframework.beans.factory.ObjectProvider;
@@ -44,6 +48,7 @@
  *
  * @author Andy Wilkinson
  * @author Stephane Nicoll
+ * @author Moritz Halbritter
  */
 @ProjectGenerationConfiguration
 @ConditionalOnLanguage(KotlinLanguage.ID)
@@ -79,6 +84,15 @@ public TestSourceCodeProjectContributor<KotlinTypeDeclaration, KotlinCompilation
 				testSourceCodeCustomizers);
 	}
 
+	@Bean
+	@ConditionalOnBuildSystem(GradleBuildSystem.ID)
+	public GitIgnoreCustomizer kotlinGradlePluginGitIgnoreCustomizer() {
+		return (gitIgnore) -> {
+			GitIgnore.GitIgnoreSection section = gitIgnore.addSectionIfAbsent("Kotlin");
+			section.add(".kotlin");
+		};
+	}
+
 	@Bean
 	public KotlinProjectSettings kotlinProjectSettings(ObjectProvider<KotlinVersionResolver> kotlinVersionResolver,
 			InitializrMetadata metadata) {

initializr-generator-spring/src/main/java/io/spring/initializr/generator/spring/scm/git/GitIgnore.java

@@ -60,6 +60,21 @@ public void addSection(GitIgnoreSection section) {
 		this.sections.add(section);
 	}
 
+	/**
+	 * Adds a section if it doesn't already exist.
+	 * @param sectionName the name of the section
+	 * @return the newly added section or the existing one
+	 */
+	public GitIgnoreSection addSectionIfAbsent(String sectionName) {
+		GitIgnoreSection section = getSection(sectionName);
+		if (section != null) {
+			return section;
+		}
+		section = new GitIgnoreSection(sectionName);
+		addSection(section);
+		return section;
+	}
+
 	public GitIgnoreSection getSection(String sectionName) {
 		if ("general".equalsIgnoreCase(sectionName)) {
 			return this.general;

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/code/kotlin/KotlinProjectGenerationConfigurationTests.java

@@ -19,14 +19,17 @@
 import java.nio.file.Path;
 import java.util.Collections;
 
+import io.spring.initializr.generator.buildsystem.BuildSystem;
 import io.spring.initializr.generator.buildsystem.Dependency;
+import io.spring.initializr.generator.buildsystem.gradle.GradleBuildSystem;
 import io.spring.initializr.generator.buildsystem.maven.MavenBuildSystem;
 import io.spring.initializr.generator.language.kotlin.KotlinLanguage;
 import io.spring.initializr.generator.packaging.war.WarPackaging;
 import io.spring.initializr.generator.project.MutableProjectDescription;
 import io.spring.initializr.generator.spring.build.BuildProjectGenerationConfiguration;
 import io.spring.initializr.generator.spring.build.maven.MavenProjectGenerationConfiguration;
 import io.spring.initializr.generator.spring.code.SourceCodeProjectGenerationConfiguration;
+import io.spring.initializr.generator.spring.scm.git.GitProjectGenerationConfiguration;
 import io.spring.initializr.generator.test.InitializrMetadataTestBuilder;
 import io.spring.initializr.generator.test.project.ProjectAssetTester;
 import io.spring.initializr.generator.test.project.ProjectStructure;
@@ -42,6 +45,7 @@
  * Tests for {@link KotlinProjectGenerationConfiguration}.
  *
  * @author Stephane Nicoll
+ * @author Moritz Halbritter
  */
 class KotlinProjectGenerationConfigurationTests {
 
@@ -52,7 +56,7 @@ void setup(@TempDir Path directory) {
 		this.projectTester = new ProjectAssetTester().withIndentingWriterFactory()
 			.withConfiguration(SourceCodeProjectGenerationConfiguration.class,
 					KotlinProjectGenerationConfiguration.class, BuildProjectGenerationConfiguration.class,
-					MavenProjectGenerationConfiguration.class)
+					MavenProjectGenerationConfiguration.class, GitProjectGenerationConfiguration.class)
 			.withDirectory(directory)
 			.withBean(InitializrMetadata.class, () -> {
 				io.spring.initializr.metadata.Dependency dependency = io.spring.initializr.metadata.Dependency
@@ -65,7 +69,9 @@ void setup(@TempDir Path directory) {
 				if (description.getPlatformVersion() == null) {
 					description.setPlatformVersion(Version.parse("2.1.0.RELEASE"));
 				}
-				description.setBuildSystem(new MavenBuildSystem());
+				if (description.getBuildSystem() == null) {
+					description.setBuildSystem(new MavenBuildSystem());
+				}
 			});
 	}
 
@@ -125,4 +131,12 @@ void jacksonKotlinModuleShouldBeAddedWhenJsonFacetPresent() {
 					"            <artifactId>jackson-module-kotlin</artifactId>", "        </dependency>");
 	}
 
+	@Test
+	void addsKotlinGradlePluginGitIgnoreEntry() {
+		MutableProjectDescription description = new MutableProjectDescription();
+		description.setBuildSystem(BuildSystem.forId(GradleBuildSystem.ID));
+		ProjectStructure project = this.projectTester.generate(description);
+		assertThat(project).textFile(".gitignore").contains("### Kotlin ###", ".kotlin");
+	}
+
 }

initializr-generator-spring/src/test/java/io/spring/initializr/generator/spring/scm/git/GitIgnoreTests.java

@@ -58,6 +58,15 @@ void shouldFailIfSectionAlreadyExists() {
 			.withMessageContaining("Section with name 'test' already exists");
 	}
 
+	@Test
+	void addSectionIfAbsentShouldNotFail() {
+		GitIgnore.GitIgnoreSection section = this.gitIgnore.addSectionIfAbsent("test");
+		assertThat(section).isNotNull();
+		GitIgnore.GitIgnoreSection section2 = this.gitIgnore.addSectionIfAbsent("test");
+		assertThat(section2).isNotNull();
+		assertThat(section2).isSameAs(section);
+	}
+
 	private String write(GitIgnore gitIgnore) throws IOException {
 		StringWriter stringWriter = new StringWriter();
 		try (PrintWriter writer = new PrintWriter(stringWriter)) {

initializr-service-sample/src/main/resources/application.yml

@@ -1,4 +1,7 @@
 initializr:
+  env:
+    kotlin:
+      default-version: "1.9.22"
   group-id:
     value: org.acme
   dependencies:
@@ -18,8 +21,10 @@ initializr:
       id: groovy
       default: false
   javaVersions:
-    - id: 11
+    - id: 17
       default: true
+    - id: 11
+      default: false
     - id: 1.8
       name: 8
       default: false