Improve handling of dependencies with invalid poms

Closes gh-365

src/main/java/io/spring/gradle/dependencymanagement/internal/maven/EffectiveModelBuilder.java

@@ -57,7 +57,10 @@ List<Model> buildModels(List<ModelInput> inputs) {
 		List<Model> models = new ArrayList<>();
 		InMemoryModelCache cache = new InMemoryModelCache();
 		for (ModelInput input : inputs) {
-			models.add(buildModel(input, cache));
+			Model model = buildModel(input, cache);
+			if (model != null) {
+				models.add(model);
+			}
 		}
 		return models;
 	}
@@ -70,10 +73,7 @@ private Model buildModel(ModelInput input, InMemoryModelCache cache) {
 		request.setModelCache(cache);
 		try {
 			ModelBuildingResult result = createModelBuilder(input.properties).build(request);
-			List<ModelProblem> errors = extractErrors(result.getProblems());
-			if (!errors.isEmpty()) {
-				reportErrors(errors, input.pom);
-			}
+			reportErrors(extractErrors(result.getProblems()), input.pom);
 			return result.getEffectiveModel();
 		}
 		catch (ModelBuildingException ex) {
@@ -86,15 +86,19 @@ private Model buildModel(ModelInput input, InMemoryModelCache cache) {
 	private List<ModelProblem> extractErrors(List<ModelProblem> problems) {
 		List<ModelProblem> errors = new ArrayList<>();
 		for (ModelProblem problem : problems) {
-			if (problem.getSeverity() == ModelProblem.Severity.ERROR) {
+			if (problem.getSeverity() == ModelProblem.Severity.ERROR
+					|| problem.getSeverity() == ModelProblem.Severity.FATAL) {
 				errors.add(problem);
 			}
 		}
 		return errors;
 	}
 
 	private void reportErrors(List<ModelProblem> errors, File file) {
-		StringBuilder message = new StringBuilder("Errors occurred while build effective model from " + file + ":");
+		if (errors.isEmpty()) {
+			return;
+		}
+		StringBuilder message = new StringBuilder("Errors occurred while building effective model from " + file + ":");
 		for (ModelProblem error : errors) {
 			message.append("\n	" + error.getMessage() + " in " + error.getModelId());
 		}

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

@@ -25,6 +25,7 @@
 import java.util.Arrays;
 import java.util.List;
 
+import org.gradle.testkit.runner.BuildResult;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.RegisterExtension;
 
@@ -502,6 +503,13 @@ void resolutionSucceedsWhenDependencyReliesOnConstraintsFromPlatformDependencies
 				"spring-jcl-5.3.27.jar");
 	}
 
+	@Test
+	void resolutionSucceedsWhenDependencyHasAnInvalidPom() {
+		BuildResult result = this.gradleBuild.runner().withArguments("resolve").build();
+		assertThat(result.getOutput()).contains("Errors occurred while building effective model")
+			.contains("Building this project requires a newer version of Maven");
+	}
+
 	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/resolutionSucceedsWhenDependencyHasAnInvalidPom.gradle

@@ -0,0 +1,24 @@
+plugins {
+	id "java"
+	id "io.spring.dependency-management"
+}
+
+repositories {
+	mavenCentral()
+}
+
+dependencies {
+	// Invalid model version
+	implementation("org.eclipse.platform:org.eclipse.core.contenttype:3.8.200")
+	// Self-referential pom
+	implementation("eu.fraho.spring:security-jwt-base-spring-boot-starter:4.6.7")
+}
+
+tasks.register("resolve") {
+	doFirst {
+		def files = project.configurations.runtimeClasspath.resolve()
+		def output = new File("${buildDir}/resolved.txt")
+		output.parentFile.mkdirs()
+		files.collect { it.name }.each { output << "${it}\n" }
+	}
+}