Fix configuration of environment in Kotlin bootBuildImage examples

Fixes gh-22913

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/build.gradle

@@ -72,6 +72,7 @@ task dependencyVersions(type: org.springframework.boot.build.constraints.Extract
 
 tasks.withType(org.asciidoctor.gradle.jvm.AbstractAsciidoctorTask) {
 	dependsOn dependencyVersions
+	inputs.dir('src/docs/gradle').withPathSensitivity(PathSensitivity.RELATIVE)
 	doFirst {
 		attributes "dependency-management-plugin-version": dependencyVersions.versionConstraints["io.spring.gradle:dependency-management-plugin"]
 	}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/packaging/boot-build-image-env-proxy.gradle

@@ -15,3 +15,9 @@ bootBuildImage {
 	]
 }
 // end::env[]
+
+task bootBuildImageEnvironment {
+	doFirst {
+		bootBuildImage.environment.each { name, value -> println "$name=$value" } 		
+	}
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/packaging/boot-build-image-env-proxy.gradle.kts

-import org.springframework.boot.gradle.tasks.bundling.BootJar
+import org.springframework.boot.gradle.tasks.bundling.BootBuildImage
 
 plugins {
 	java
 	id("org.springframework.boot") version "{gradle-project-version}"
 }
 
-tasks.getByName<BootJar>("bootJar") {
-	mainClassName = "com.example.ExampleApplication"
-}
-
 // tag::env[]
 tasks.getByName<BootBuildImage>("bootBuildImage") {
-	environment = [
-		"HTTP_PROXY" : "http://proxy.example.com",
-		"HTTPS_PROXY" : "https://proxy.example.com"
-	]
+	environment = mapOf("HTTP_PROXY" to "http://proxy.example.com",
+						"HTTPS_PROXY" to "https://proxy.example.com")
 }
 // end::env[]
+
+tasks.register("bootBuildImageEnvironment") {
+	doFirst {
+		for((name, value) in tasks.getByName<BootBuildImage>("bootBuildImage").environment) {
+			print(name + "=" + value)
+		}
+	}
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/packaging/boot-build-image-env.gradle

@@ -12,3 +12,9 @@ bootBuildImage {
 	environment = ["BP_JVM_VERSION" : "13.0.1"]
 }
 // end::env[]
+
+task bootBuildImageEnvironment {
+	doFirst {
+		bootBuildImage.environment.each { name, value -> println "$name=$value" } 		
+	}
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/gradle/packaging/boot-build-image-env.gradle.kts

-import org.springframework.boot.gradle.tasks.bundling.BootJar
+import org.springframework.boot.gradle.tasks.bundling.BootBuildImage
 
 plugins {
 	java
 	id("org.springframework.boot") version "{gradle-project-version}"
 }
 
-tasks.getByName<BootJar>("bootJar") {
-	mainClassName = "com.example.ExampleApplication"
-}
-
 // tag::env[]
 tasks.getByName<BootBuildImage>("bootBuildImage") {
-	environment = ["BP_JVM_VERSION" : "13.0.1"]
+	environment = mapOf("BP_JVM_VERSION" to "13.0.1")
 }
 // end::env[]
+
+tasks.register("bootBuildImageEnvironment") {
+	doFirst {
+		for((name, value) in tasks.getByName<BootBuildImage>("bootBuildImage").environment) {
+			print(name + "=" + value)
+		}
+	}
+}
+

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/docs/PackagingDocumentationTests.java

@@ -28,6 +28,7 @@ import java.util.jar.JarOutputStream;
 import java.util.jar.Manifest;
 import java.util.zip.ZipEntry;
 
+import org.gradle.testkit.runner.BuildResult;
 import org.junit.jupiter.api.TestTemplate;
 import org.junit.jupiter.api.extension.ExtendWith;
 
@@ -221,6 +222,21 @@ class PackagingDocumentationTests {
 		}
 	}
 
+	@TestTemplate
+	void bootBuildImageWithCustomBuildpackJvmVersion() throws IOException {
+		BuildResult result = this.gradleBuild.script("src/docs/gradle/packaging/boot-build-image-env")
+				.build("bootBuildImageEnvironment");
+		assertThat(result.getOutput()).contains("BP_JVM_VERSION=13.0.1");
+	}
+
+	@TestTemplate
+	void bootBuildImageWithCustomProxySettings() throws IOException {
+		BuildResult result = this.gradleBuild.script("src/docs/gradle/packaging/boot-build-image-env-proxy")
+				.build("bootBuildImageEnvironment");
+		assertThat(result.getOutput()).contains("HTTP_PROXY=http://proxy.example.com")
+				.contains("HTTPS_PROXY=https://proxy.example.com");
+	}
+
 	protected void jarFile(File file) throws IOException {
 		try (JarOutputStream jar = new JarOutputStream(new FileOutputStream(file))) {
 			jar.putNextEntry(new ZipEntry("META-INF/MANIFEST.MF"));