Correct grouping of custom buildpacks

This commit corrects the order.toml file that is generated and added
to the builder when building an image using custom buildpacks with the
Maven or Gradle plugin in order to support buildpacks that depend on
detection as a group.

Fixes gh-25378

Author: scottfrederick

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/build/Buildpacks.java

@@ -63,22 +63,20 @@ void addOrderLayerContent(Layout layout) throws IOException {
 
 	private String getOrderToml() {
 		StringBuilder builder = new StringBuilder();
+		builder.append("[[order]]\n\n");
 		for (Buildpack buildpack : this.buildpacks) {
 			appendToOrderToml(builder, buildpack.getCoordinates());
 		}
 		return builder.toString();
 	}
 
 	private void appendToOrderToml(StringBuilder builder, BuildpackCoordinates coordinates) {
-		builder.append("[[order]]\n");
-		builder.append("group = [\n");
-		builder.append("  { ");
-		builder.append("id = \"" + coordinates.getId() + "\"");
+		builder.append("  [[order.group]]\n");
+		builder.append("    id = \"" + coordinates.getId() + "\"\n");
 		if (StringUtils.hasText(coordinates.getVersion())) {
-			builder.append(", version = \"" + coordinates.getVersion() + "\"");
+			builder.append("    version = \"" + coordinates.getVersion() + "\"\n");
 		}
-		builder.append(" }\n");
-		builder.append("]\n\n");
+		builder.append("\n");
 	}
 
 	static Buildpacks of(List<Buildpack> buildpacks) {

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/build/BuildpacksTests.java

@@ -94,17 +94,18 @@ private void assertThatOrderLayerContentIsCorrect(Layer layer) throws IOExceptio
 	private String getExpectedToml() {
 		StringBuilder toml = new StringBuilder();
 		toml.append("[[order]]\n");
-		toml.append("group = [\n");
-		toml.append("  { id = \"example/buildpack1\", version = \"0.0.1\" }\n");
-		toml.append("]\n\n");
-		toml.append("[[order]]\n");
-		toml.append("group = [\n");
-		toml.append("  { id = \"example/buildpack2\", version = \"0.0.2\" }\n");
-		toml.append("]\n\n");
-		toml.append("[[order]]\n");
-		toml.append("group = [\n");
-		toml.append("  { id = \"example/buildpack3\" }\n");
-		toml.append("]\n\n");
+		toml.append("\n");
+		toml.append("  [[order.group]]\n");
+		toml.append("    id = \"example/buildpack1\"\n");
+		toml.append("    version = \"0.0.1\"\n");
+		toml.append("\n");
+		toml.append("  [[order.group]]\n");
+		toml.append("    id = \"example/buildpack2\"\n");
+		toml.append("    version = \"0.0.2\"\n");
+		toml.append("\n");
+		toml.append("  [[order.group]]\n");
+		toml.append("    id = \"example/buildpack3\"\n");
+		toml.append("\n");
 		return toml.toString();
 	}
 

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/build/EphemeralBuilderTests.java

@@ -146,7 +146,7 @@ void getArchiveContainsBuildpackLayers() throws Exception {
 		assertBuildpackLayerContent(builder, 2, "/cnb/buildpacks/example_buildpack3/0.0.3/buildpack.toml");
 		File orderDirectory = unpack(getLayer(builder.getArchive(), 3), "order");
 		assertThat(new File(orderDirectory, "cnb/order.toml")).usingCharset(StandardCharsets.UTF_8)
-				.hasContent(content("order-versions.toml"));
+				.hasContent(content("order.toml"));
 	}
 
 	private void assertBuildpackLayerContent(EphemeralBuilder builder, int index, String s) throws Exception {

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/resources/org/springframework/boot/buildpack/platform/build/order-versions.toml

@@ -1,15 +1,14 @@
 [[order]]
-group = [
-  { id = "example/buildpack1" }
-]
 
-[[order]]
-group = [
-  { id = "example/buildpack2" }
-]
+  [[order.group]]
+    id = "example/buildpack1"
+    version = "0.0.1"
 
-[[order]]
-group = [
-  { id = "example/buildpack3" }
-]
+  [[order.group]]
+    id = "example/buildpack2"
+    version = "0.0.2"
+
+  [[order.group]]
+    id = "example/buildpack3"
+    version = "0.0.3"
 

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/resources/org/springframework/boot/buildpack/platform/build/order.toml

@@ -203,7 +203,7 @@ void buildsImageWithBuildpackFromTarGzip() throws IOException {
 	}
 
 	@TestTemplate
-	void buildsImageWithBuildpackFromImage() throws IOException {
+	void buildsImageWithBuildpacksFromImages() throws IOException {
 		writeMainClass();
 		writeLongNameResource();
 		BuildResult result = this.gradleBuild.build("bootBuildImage", "--pullPolicy=IF_NOT_PRESENT");

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootBuildImageIntegrationTests.java

@@ -0,0 +1,13 @@
+plugins {
+	id 'java'
+	id 'org.springframework.boot' version '{version}'
+}
+
+sourceCompatibility = '1.8'
+targetCompatibility = '1.8'
+
+bootBuildImage {
+	buildpacks = ["gcr.io/paketo-buildpacks/bellsoft-liberica:latest",
+				  "gcr.io/paketo-buildpacks/executable-jar:latest",
+				  "gcr.io/paketo-buildpacks/spring-boot:latest"]
+}

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/resources/org/springframework/boot/gradle/tasks/bundling/BootBuildImageIntegrationTests-buildsImageWithBuildpackFromImage.gradle

@@ -24,7 +24,9 @@
 						<configuration>
 							<image>
 								<buildpacks>
-									<buildpack>paketo-buildpacks/java</buildpack>
+									<buildpack>gcr.io/paketo-buildpacks/bellsoft-liberica:latest</buildpack>
+									<buildpack>gcr.io/paketo-buildpacks/executable-jar:latest</buildpack>
+									<buildpack>gcr.io/paketo-buildpacks/spring-boot:latest</buildpack>
 								</buildpacks>
 							</image>
 						</configuration>