Merge pull request #22918 from jnizet

* pr/22918:
  Fix custom image name example and documentation

Closes gh-22918

Author: snicoll

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/docs/asciidoc/packaging-oci-image.adoc

@@ -59,7 +59,7 @@ The following table summarizes the available properties and their default values
 | `imageName`
 | `--imageName`
 | {spring-boot-api}/buildpack/platform/docker/type/ImageReference.html#of-java.lang.String-[Image name] for the generated image.
-| `docker.io/library/${project.artifactId}:${project.version}`
+| `docker.io/library/${project.name}:${project.version}`
 
 | `environment`
 |
@@ -149,7 +149,7 @@ include::../gradle/packaging/boot-build-image-env-proxy.gradle.kts[tags=env]
 
 [[build-image-example-custom-image-name]]
 ==== Custom Image Name
-By default, the image name is inferred from the `artifactId` and the `version` of the project, something like `docker.io/library/${project.artifactId}:${project.version}`.
+By default, the image name is inferred from the `name` and the `version` of the project, something like `docker.io/library/${project.name}:${project.version}`.
 You can take control over the name by setting task properties, as shown in the following example:
 
 [source,groovy,indent=0,subs="verbatim,attributes",role="primary"]

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

@@ -3,12 +3,14 @@ plugins {
 	id 'org.springframework.boot' version '{gradle-project-version}'
 }
 
-bootJar {
-	mainClassName 'com.example.ExampleApplication'
-}
-
 // tag::image-name[]
 bootBuildImage {
-	imageName = "example.com/library/${project.artifactId}"
+	imageName = "example.com/library/${project.name}"
 }
 // end::image-name[]
+
+task bootBuildImageName {
+    doFirst {
+        println(tasks.bootBuildImage.imageName)
+    }
+}

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

@@ -1,16 +1,18 @@
-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::image-name[]
 tasks.getByName<BootBuildImage>("bootBuildImage") {
-	imageName = "example.com/library/${project.artifactId}"
+	imageName = "example.com/library/${project.name}"
 }
 // end::image-name[]
+
+tasks.register("bootBuildImageName") {
+    doFirst {
+        println(tasks.getByName<BootBuildImage>("bootBuildImage").imageName)
+    }
+}

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

@@ -237,6 +237,13 @@ void bootBuildImageWithCustomProxySettings() throws IOException {
 				.contains("HTTPS_PROXY=https://proxy.example.com");
 	}
 
+	@TestTemplate
+	void bootBuildImageWithCustomImageName() throws IOException {
+		BuildResult result = this.gradleBuild.script("src/docs/gradle/packaging/boot-build-image-name")
+				.build("bootBuildImageName");
+		assertThat(result.getOutput()).contains("example.com/library/" + this.gradleBuild.getProjectDir().getName());
+	}
+
 	protected void jarFile(File file) throws IOException {
 		try (JarOutputStream jar = new JarOutputStream(new FileOutputStream(file))) {
 			jar.putNextEntry(new ZipEntry("META-INF/MANIFEST.MF"));