From 3f806aa513d5cd79227c62e1c76ea99f51397f75 Mon Sep 17 00:00:00 2001
From: Phillip Webb <pwebb@pivotal.io>
Date: Thu, 2 Apr 2020 23:55:52 -0700
Subject: [PATCH] Create a new layer for loader classes

Create a dedicated layer that is used to hold the launcher support
classes. The layer sits between `dependencies` and
`snapshot-dependencies` so that the layer is sensible for both
SNAPSHOT and RELEASE versions of Spring Boot

Closes gh-20529
---
 .../boot/gradle/tasks/bundling/BootJarTests.java            | 2 +-
 .../boot/loader/tools/ImplicitLayerResolver.java            | 5 +++++
 .../springframework/boot/loader/tools/StandardLayers.java   | 6 ++++++
 .../boot/loader/tools/ImplicitLayerResolverTests.java       | 4 ++--
 4 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootJarTests.java b/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootJarTests.java
index 562f849e7c..710ab6a0a4 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootJarTests.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/src/test/java/org/springframework/boot/gradle/tasks/bundling/BootJarTests.java
@@ -100,7 +100,7 @@ class BootJarTests extends AbstractBootArchiveTests<TestBootJar> {
 	@Test
 	void whenJarIsLayeredThenLayersIndexIsPresentAndListsLayersInOrder() throws IOException {
 		try (JarFile jarFile = new JarFile(createLayeredJar())) {
-			assertThat(entryLines(jarFile, "BOOT-INF/layers.idx")).containsExactly("dependencies",
+			assertThat(entryLines(jarFile, "BOOT-INF/layers.idx")).containsExactly("dependencies", "spring-boot-loader",
 					"snapshot-dependencies", "application");
 		}
 	}
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/ImplicitLayerResolver.java b/spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/ImplicitLayerResolver.java
index f585819074..ca97b6f3bb 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/ImplicitLayerResolver.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/ImplicitLayerResolver.java
@@ -24,8 +24,13 @@ package org.springframework.boot.loader.tools;
  */
 class ImplicitLayerResolver extends StandardLayers {
 
+	private static final String SPRING_BOOT_LOADER_PREFIX = "org/springframework/boot/loader/";
+
 	@Override
 	public Layer getLayer(String name) {
+		if (name.startsWith(SPRING_BOOT_LOADER_PREFIX)) {
+			return SPRING_BOOT_LOADER;
+		}
 		return APPLICATION;
 	}
 
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/StandardLayers.java b/spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/StandardLayers.java
index 2a8f9ea82e..b55e777814 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/StandardLayers.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/StandardLayers.java
@@ -41,6 +41,11 @@ public abstract class StandardLayers implements Layers {
 	 */
 	public static final Layer DEPENDENCIES = new Layer("dependencies");
 
+	/**
+	 * The spring boot loader layer.
+	 */
+	public static final Layer SPRING_BOOT_LOADER = new Layer("spring-boot-loader");
+
 	/**
 	 * The snapshot dependencies layer.
 	 */
@@ -55,6 +60,7 @@ public abstract class StandardLayers implements Layers {
 	static {
 		List<Layer> layers = new ArrayList<>();
 		layers.add(DEPENDENCIES);
+		layers.add(SPRING_BOOT_LOADER);
 		layers.add(SNAPSHOT_DEPENDENCIES);
 		layers.add(APPLICATION);
 		LAYERS = Collections.unmodifiableList(layers);
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/test/java/org/springframework/boot/loader/tools/ImplicitLayerResolverTests.java b/spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/test/java/org/springframework/boot/loader/tools/ImplicitLayerResolverTests.java
index 6fe9637ea4..49c2a48c83 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/test/java/org/springframework/boot/loader/tools/ImplicitLayerResolverTests.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/test/java/org/springframework/boot/loader/tools/ImplicitLayerResolverTests.java
@@ -34,8 +34,8 @@ class ImplicitLayerResolverTests {
 
 	@Test
 	void iteratorReturnsLayers() {
-		assertThat(this.layers).containsExactly(StandardLayers.DEPENDENCIES, StandardLayers.SNAPSHOT_DEPENDENCIES,
-				StandardLayers.APPLICATION);
+		assertThat(this.layers).containsExactly(StandardLayers.DEPENDENCIES, StandardLayers.SPRING_BOOT_LOADER,
+				StandardLayers.SNAPSHOT_DEPENDENCIES, StandardLayers.APPLICATION);
 	}
 
 	@Test