Remove side-effect on bom ordering when configuring pom's dep mgmt

See gh-355

src/main/java/io/spring/gradle/dependencymanagement/internal/StandardPomDependencyManagementConfigurer.java

@@ -39,6 +39,7 @@
  * Standard implementation of {@link PomDependencyManagementConfigurer}.
  *
  * @author Andy Wilkinson
+ * @author Rupert Waldron
  */
 public class StandardPomDependencyManagementConfigurer implements PomDependencyManagementConfigurer {
 
@@ -144,8 +145,11 @@ private void configureBomImports(Node dependencies) {
 			appendDependencyNode(dependencies, override.getCoordinates(), override.getScope(), override.getType());
 		}
 		List<PomReference> importedBoms = this.dependencyManagement.getImportedBomReferences();
-		Collections.reverse(importedBoms);
-		for (PomReference resolvedBom : importedBoms) {
+
+		List<PomReference> importedBomsCopy = new ArrayList<>(importedBoms);
+		Collections.reverse(importedBomsCopy);
+
+		for (PomReference resolvedBom : importedBomsCopy) {
 			addImport(dependencies, resolvedBom);
 		}
 	}

src/test/java/io/spring/gradle/dependencymanagement/DependencyManagementPluginIntegrationTests.java

@@ -34,6 +34,7 @@
  * Integration tests for {@link DependencyManagementPlugin}.
  *
  * @author Andy Wilkinson
+ * @author Rupert Waldron
  */
 class DependencyManagementPluginIntegrationTests {
 
@@ -336,6 +337,12 @@ void bomImportOrderIsReflectedInManagedVersionsWhenSameBomIsImportedMultipleTime
 		assertThat(readLines("managed-versions.txt")).contains("org.springframework:spring-core -> 4.2.3.RELEASE");
 	}
 
+	@Test
+	void bomImportOrderIsReflectedInManagedVersionsWhenThePomIsPublished() {
+		this.gradleBuild.runner().withArguments("managedVersionsAfterPublishPom").build();
+		assertThat(readLines("managed-versions.txt")).contains("org.springframework:spring-core -> 4.2.3.RELEASE");
+	}
+
 	@Test
 	void managedVersionsOfAConfigurationCanBeAccessed() {
 		this.gradleBuild.runner().withArguments("verify").build();

src/test/resources/io/spring/gradle/dependencymanagement/DMPIT/bomImportOrderIsReflectedInManagedVersionsWhenThePomIsPublished.gradle

@@ -0,0 +1,40 @@
+plugins {
+	id "io.spring.dependency-management"
+	id "java"
+	id 'maven-publish'
+}
+
+repositories {
+	mavenCentral()
+}
+
+dependencyManagement {
+	imports {
+		mavenBom 'org.springframework.boot:spring-boot-dependencies:1.2.7.RELEASE'
+		mavenBom 'io.spring.platform:platform-bom:2.0.0.RELEASE'
+	}
+}
+
+publishing {
+	publications {
+		maven(MavenPublication) {
+			groupId = 'group-id'
+			artifactId = 'dep-management'
+			version = '1.0'
+
+			from components.java
+		}
+	}
+}
+
+
+task managedVersionsAfterPublishPom {
+	dependsOn generatePomFileForMavenPublication
+	doFirst {
+		def output = new File("${buildDir}/managed-versions.txt")
+		output.parentFile.mkdirs()
+		dependencyManagement.managedVersions.each { key, value ->
+			output << "${key} -> ${value}\n"
+		}
+	}
+}