Identify Checkstyle version if using a transitive one from the Maven plugin

Author: nrayburn-tech

src/main/java/org/infernus/idea/checkstyle/maven/MavenCheckstyleConfigurator.java

@@ -1,17 +1,21 @@
 package org.infernus.idea.checkstyle.maven;
 
 import com.intellij.openapi.project.Project;
+import com.intellij.openapi.vfs.VirtualFileManager;
 import java.io.File;
+import java.io.FileReader;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.nio.file.Files;
 import java.nio.file.InvalidPathException;
 import java.nio.file.Path;
 import java.util.Comparator;
+import java.util.Objects;
 import java.util.Spliterator;
 import java.util.Spliterators;
 import java.util.TreeSet;
 import java.util.stream.StreamSupport;
+import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
 import org.infernus.idea.checkstyle.CheckstyleProjectService;
 import org.infernus.idea.checkstyle.config.PluginConfigurationBuilder;
 import org.infernus.idea.checkstyle.config.PluginConfigurationManager;
@@ -23,10 +27,13 @@
 import org.jdom.Element;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jetbrains.idea.maven.dom.MavenDomUtil;
+import org.jetbrains.idea.maven.dom.MavenPropertyResolver;
 import org.jetbrains.idea.maven.importing.MavenAfterImportConfigurator;
 import org.jetbrains.idea.maven.importing.MavenWorkspaceConfigurator.MavenProjectWithModules;
 import org.jetbrains.idea.maven.model.MavenId;
 import org.jetbrains.idea.maven.project.MavenProject;
+import org.jetbrains.idea.maven.utils.MavenArtifactUtil;
 
 /**
  * Importer to automatically configure the Checkstyle IntelliJ plugin settings based on the
@@ -62,22 +69,39 @@ public void afterImport(@NotNull final MavenAfterImportConfigurator.Context cont
         final var checkstyleMavenPlugin = mavenProject.findPlugin(
             MAVEN_CHECKSTYLE_PLUGIN_MAVEN_ID.getGroupId(),
             MAVEN_CHECKSTYLE_PLUGIN_MAVEN_ID.getArtifactId());
-
         if (checkstyleMavenPlugin == null) {
             return;
         }
 
         final var checkstyleDependencyMavenId = checkstyleMavenPlugin.getDependencies().stream()
             .filter(dependency -> CHECKSTYLE_MAVEN_ID.equals(dependency.getGroupId(),
-                dependency.getArtifactId())).findFirst().orElse(null);
+                dependency.getArtifactId())).findFirst().orElseGet(() -> {
+                final var mavenPluginPath = MavenArtifactUtil.getArtifactFile(
+                    mavenProject.getLocalRepository(), checkstyleMavenPlugin.getMavenId(), "pom");
+
+                try {
+                    final var mavenReader = new MavenXpp3Reader();
+                    final var model = mavenReader.read(new FileReader(mavenPluginPath.toFile()));
+                    final var checkstyleDependency = model.getDependencies().stream().filter(
+                        dependency -> CHECKSTYLE_MAVEN_ID.equals(dependency.getGroupId(),
+                            dependency.getArtifactId())).findFirst().orElseThrow();
+                    final var mavenPluginVirtualFile = VirtualFileManager.getInstance()
+                        .findFileByNioPath(mavenPluginPath);
+                    final var mavenDomProjectModel = MavenDomUtil.getMavenDomProjectModel(project,
+                        Objects.requireNonNull(mavenPluginVirtualFile));
+                    final var version = MavenPropertyResolver.resolve(
+                        checkstyleDependency.getVersion(),
+                        Objects.requireNonNull(mavenDomProjectModel));
+                    return new MavenId(checkstyleDependency.getGroupId(),
+                        checkstyleDependency.getArtifactId(), version);
+                } catch (final Exception exception) {
+                    throw new RuntimeException(exception);
+                }
+            });
 
         final var pluginConfigurationBuilder = PluginConfigurationBuilder.from(
             currentPluginConfiguration);
-        // TODO: This will be null if checkstyle isn't declared explicitly.
-        //  Meaning the transitive dependency version won't be found.
-        //  Would be great to resolve that transitive version somehow.
-        if (checkstyleDependencyMavenId != null
-            && checkstyleDependencyMavenId.getVersion() != null) {
+        if (checkstyleDependencyMavenId.getVersion() != null) {
             // Checkstyle Version
             pluginConfigurationBuilder.withCheckstyleVersion(
                 checkstyleDependencyMavenId.getVersion());