Consider constraints when copy configuration to determine exclusions

Closes gh-340

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

@@ -27,6 +27,8 @@
 import io.spring.gradle.dependencymanagement.internal.DependencyManagementConfigurationContainer.ConfigurationConfigurer;
 import org.gradle.api.Action;
 import org.gradle.api.artifacts.Configuration;
+import org.gradle.api.artifacts.Dependency;
+import org.gradle.api.artifacts.DependencyConstraintSet;
 import org.gradle.api.artifacts.DependencySet;
 import org.gradle.api.artifacts.ModuleDependency;
 import org.gradle.api.artifacts.ResolvableDependencies;
@@ -106,10 +108,7 @@ private void applyMavenExclusions(ResolvableDependencies resolvableDependencies)
 	}
 
 	private Set<DependencyCandidate> findExcludedDependencies() {
-		DependencySet allDependencies = this.configuration.getAllDependencies();
-		Configuration configurationCopy = this.configurationContainer.newConfiguration(this.configurationConfigurer,
-				allDependencies.toArray(new org.gradle.api.artifacts.Dependency[allDependencies.size()]));
-		ResolutionResult resolutionResult = configurationCopy.getIncoming().getResolutionResult();
+		ResolutionResult resolutionResult = copyConfiguration().getIncoming().getResolutionResult();
 		ResolvedComponentResult root = resolutionResult.getRoot();
 		final Set<DependencyCandidate> excludedDependencies = new HashSet<DependencyCandidate>();
 		resolutionResult.allDependencies(new Action<DependencyResult>() {
@@ -136,6 +135,20 @@ else if (dependencyResult instanceof UnresolvedDependencyResult) {
 		return excludedDependencies;
 	}
 
+	private Configuration copyConfiguration() {
+		DependencySet allDependencies = this.configuration.getAllDependencies();
+		Configuration configurationCopy = this.configurationContainer.newConfiguration(this.configurationConfigurer,
+				allDependencies.toArray(new Dependency[allDependencies.size()]));
+		try {
+			DependencyConstraintSet constraints = this.configuration.getAllDependencyConstraints();
+			configurationCopy.getDependencyConstraints().addAll(constraints);
+		}
+		catch (NoSuchMethodError ex) {
+			// Continue
+		}
+		return configurationCopy;
+	}
+
 	private Set<DependencyCandidate> determineIncludedComponents(ResolvedComponentResult root,
 			Map<String, Exclusions> pomExclusionsById) {
 		LinkedList<Node> queue = new LinkedList<Node>();

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

@@ -462,6 +462,13 @@ void exclusionThatIsMalformedIsTolerated() {
 				"commons-logging-1.1.3.jar");
 	}
 
+	@Test
+	void exclusionsAreAppliedToDependenciesVersionedWithConstraints() {
+		this.gradleBuild.runner().withArguments("resolve").build();
+		assertThat(readLines("resolved.txt")).containsOnly("transitive-exclude-1.0.jar",
+				"spring-beans-4.1.2.RELEASE.jar", "spring-tx-4.1.2.RELEASE.jar", "spring-core-4.1.2.RELEASE.jar");
+	}
+
 	private void writeLines(Path path, String... lines) {
 		try {
 			Path resolvedPath = this.gradleBuild.runner().getProjectDir().toPath().resolve(path);

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

@@ -0,0 +1,27 @@
+plugins {
+	id "io.spring.dependency-management"
+	id "java"
+}
+
+repositories {
+	mavenCentral()
+	maven {
+		url file("maven-repo")
+	}
+}
+
+dependencies {
+	implementation 'test:transitive-exclude'
+	constraints {
+		implementation 'test:transitive-exclude:1.0'
+	}
+}
+
+task resolve {
+	doFirst {
+		def files = project.configurations.compileClasspath.resolve()
+		def output = new File("${buildDir}/resolved.txt")
+		output.parentFile.mkdirs()
+		files.collect { it.name }.each { output << "${it}\n" }
+	}
+}