Use -parameters compiler arg by default in Gradle builds

See gh-9839

spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/JavaPluginAction.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.gradle.plugin;
 
 import java.util.Collections;
+import java.util.List;
 import java.util.concurrent.Callable;
 
 import org.gradle.api.Action;
@@ -41,6 +42,7 @@ import org.springframework.boot.gradle.tasks.run.BootRun;
  */
 final class JavaPluginAction implements PluginApplicationAction {
 
+	private static final String PARAMETERS_COMPILER_ARG = "-parameters";
 	private final SinglePublishedArtifact singlePublishedArtifact;
 
 	JavaPluginAction(SinglePublishedArtifact singlePublishedArtifact) {
@@ -60,6 +62,7 @@ final class JavaPluginAction implements PluginApplicationAction {
 		configureArtifactPublication(project, bootJar);
 		configureBootRunTask(project);
 		configureUtf8Encoding(project);
+		configureParametersCompilerArg(project);
 	}
 
 	private void disableJarTask(Project project) {
@@ -121,4 +124,12 @@ final class JavaPluginAction implements PluginApplicationAction {
 				}));
 	}
 
+	private void configureParametersCompilerArg(Project project) {
+		project.getTasks().withType(JavaCompile.class, compile -> {
+			final List<String> compilerArgs = compile.getOptions().getCompilerArgs();
+			if (!compilerArgs.contains(PARAMETERS_COMPILER_ARG)) {
+				compilerArgs.add(PARAMETERS_COMPILER_ARG);
+			}
+		});
+	}
 }

spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/plugin/JavaPluginActionIntegrationTests.java

@@ -73,6 +73,37 @@ public class JavaPluginActionIntegrationTests {
 						.contains("compileTestJava = UTF-8");
 	}
 
+	@Test
+	public void javaCompileTasksUseParametersCompilerFlagByDefault() {
+		assertThat(this.gradleBuild.build("javaParametersCompilerArg", "-PapplyJavaPlugin")
+				.getOutput()).contains("compileJava has -parameters by default = true")
+				.contains("compileTestJava has -parameters by default = true");
+	}
+
+	// -parameters and an additional compiler arg
+	@Test
+	public void javaCompileTasksUseParametersCompilerFlagWhenOtherAdded() {
+		assertThat(this.gradleBuild.build("javaParametersCompilerArg", "-PapplyJavaPlugin", "-PparametersAddOther")
+				.getOutput()).contains("compileJava has -parameters when another arg has been added = true")
+				.contains("compileTestJava has -parameters when another arg has been added = true");
+	}
+
+	// -parameters removed
+	@Test
+	public void javaCompileTasksDoesNotUseParametersWhenParametersRemoved() {
+		assertThat(this.gradleBuild.build("javaParametersCompilerArg", "-PapplyJavaPlugin", "-PparametersRemove")
+				.getOutput()).contains("compileJava has -parameters when removed = false")
+				.contains("compileTestJava has -parameters when removed = false");
+	}
+
+	// compiler args cleared
+	@Test
+	public void javaCompileTasksDoesNotUseParametersWhenArgsCleared() {
+		assertThat(this.gradleBuild.build("javaParametersCompilerArg", "-PapplyJavaPlugin", "-PparametersClear")
+				.getOutput()).contains("compileJava has -parameters when cleared = false")
+				.contains("compileTestJava has -parameters when cleared = false");
+	}
+
 	@Test
 	public void assembleRunsBootJarAndJarIsSkipped() {
 		BuildResult result = this.gradleBuild.build("assemble");

spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/plugin/JavaPluginActionIntegrationTests.gradle

@@ -10,6 +10,24 @@ if (project.hasProperty('applyJavaPlugin')) {
 	apply plugin: 'java'
 }
 
+if (project.hasProperty('parametersRemove')) {
+	tasks.withType(JavaCompile) {
+		options.compilerArgs.remove('-parameters')
+	}
+}
+
+if (project.hasProperty('parametersClear')) {
+	tasks.withType(JavaCompile) {
+		options.compilerArgs.clear()
+	}
+}
+
+if (project.hasProperty('parametersAddOther')) {
+	tasks.withType(JavaCompile) {
+		options.compilerArgs.add('-Xlint:all')
+	}
+}
+
 task('taskExists') {
 	doFirst {
 		println "$taskName exists = ${tasks.findByName(taskName) != null}"
@@ -23,3 +41,20 @@ task('javaCompileEncoding') {
 		}
 	}
 }
+
+task('javaParametersCompilerArg') {
+	doFirst {
+		tasks.withType(JavaCompile) {
+			def contains = options.compilerArgs.contains('-parameters')
+			if (project.hasProperty('parametersRemove')) {
+				println "$name has -parameters when removed = ${contains}"
+			} else if (project.hasProperty('parametersClear')) {
+				println "$name has -parameters when cleared = ${contains}"
+			} else if (project.hasProperty('parametersAddOther')) {
+				println "$name has -parameters when another arg has been added = ${contains}"
+			} else {
+				println "$name has -parameters by default = ${contains}"
+			}
+		}
+	}
+}