Repackage kotlin-module metadata beneath BOOT-INF/classes

Closes gh-15890

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/Repackager.java

@@ -380,7 +380,8 @@ public class Repackager {
 				return null;
 			}
 			if ((entry.getName().startsWith("META-INF/")
-					&& !entry.getName().equals("META-INF/aop.xml"))
+					&& !entry.getName().equals("META-INF/aop.xml")
+					&& !entry.getName().endsWith(".kotlin-module"))
 					|| entry.getName().startsWith("BOOT-INF/")
 					|| entry.getName().equals("module-info.class")) {
 				return entry;

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/src/test/java/org/springframework/boot/loader/tools/RepackagerTests.java

@@ -675,6 +675,23 @@ public class RepackagerTests {
 		}
 	}
 
+	@Test
+	public void kotlinModuleMetadataMovesBeneathBootInfClassesWhenRepackaged()
+			throws Exception {
+		this.testJarFile.addClass("A.class", ClassWithMainMethod.class);
+		this.testJarFile.addFile("META-INF/test.kotlin-module",
+				this.temporaryFolder.newFile("test.kotlin-module"));
+		File source = this.testJarFile.getFile();
+		File dest = this.temporaryFolder.newFile("dest.jar");
+		Repackager repackager = new Repackager(source);
+		repackager.repackage(dest, NO_LIBRARIES);
+		try (JarFile jarFile = new JarFile(dest)) {
+			assertThat(jarFile.getEntry("META-INF/test.kotlin-module")).isNull();
+			assertThat(jarFile.getEntry("BOOT-INF/classes/META-INF/test.kotlin-module"))
+					.isNotNull();
+		}
+	}
+
 	private File createLibrary() throws IOException {
 		TestJarFile library = new TestJarFile(this.temporaryFolder);
 		library.addClass("com/example/library/Library.class",