Fix mojohaus#358 NPE on site generation caused by null returned by de…

…precated MavenProject.getDependencyArtifacts()

src/it/ISSUE-358/child-1/pom.xml

@@ -0,0 +1,11 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>net.tomred</groupId>
+    <artifactId>ISSUE-358</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+  </parent>
+  <artifactId>child-1</artifactId>
+</project>

src/it/ISSUE-358/invoker.properties

@@ -0,0 +1,2 @@
+invoker.goals=clean site
+invoker.failureBehavior=fail-fast

src/it/ISSUE-358/pom.xml

@@ -0,0 +1,51 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>net.tomred</groupId>
+  <artifactId>ISSUE-358</artifactId>
+  <version>0.0.1-SNAPSHOT</version>
+
+  <packaging>pom</packaging>
+
+  <modules>
+    <module>child-1</module>
+  </modules>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>license-maven-plugin</artifactId>
+        <version>@pom.version@</version>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-site-plugin</artifactId>
+        <version>3.9.0</version>
+        <dependencies>
+          <dependency>
+            <groupId>org.apache.maven.doxia</groupId>
+            <artifactId>doxia-site-renderer</artifactId>
+            <version>1.9.2</version>
+          </dependency>
+        </dependencies>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-project-info-reports-plugin</artifactId>
+        <version>3.0.0</version>
+      </plugin>
+    </plugins>
+  </build>
+
+  <reporting>
+    <plugins>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>license-maven-plugin</artifactId>
+        <version>@pom.version@</version>
+      </plugin>
+    </plugins>
+  </reporting>
+</project>

src/main/java/org/codehaus/mojo/license/AbstractThirdPartyReportMojo.java

@@ -555,13 +555,13 @@ Collection<ThirdPartyDetails> createThirdPartyDetails( MavenProject project, boo
         ResolvedProjectDependencies loadedDependencies;
         if ( loadArtifacts )
         {
-            loadedDependencies =
-                    new ResolvedProjectDependencies( project.getArtifacts(), project.getDependencyArtifacts() );
+            loadedDependencies = new ResolvedProjectDependencies( project.getArtifacts(),
+                    MojoHelper.getDependencyArtifacts( project ) );
         }
         else
         {
             loadedDependencies = new ResolvedProjectDependencies( getProject().getArtifacts(),
-                    getProject().getDependencyArtifacts() );
+                    MojoHelper.getDependencyArtifacts( project ) );
         }
 
         ThirdPartyHelper thirdPartyHelper =

src/main/java/org/codehaus/mojo/license/AddThirdPartyMojo.java

@@ -47,6 +47,7 @@
 import org.codehaus.mojo.license.api.ThirdPartyToolException;
 import org.codehaus.mojo.license.model.LicenseMap;
 import org.codehaus.mojo.license.utils.FileUtil;
+import org.codehaus.mojo.license.utils.MojoHelper;
 import org.codehaus.mojo.license.utils.SortedProperties;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -240,13 +241,13 @@ protected ResolvedProjectDependencies resolveDependencyArtifacts() throws Depend
         }
         if ( isAggregatorBuild )
         {
-            dependencyArtifacts =
-                    new ResolvedProjectDependencies( project.getArtifacts(), project.getDependencyArtifacts() );
+            dependencyArtifacts = new ResolvedProjectDependencies( project.getArtifacts(),
+                    MojoHelper.getDependencyArtifacts( project ) );
         }
         else
         {
             dependencyArtifacts = new ResolvedProjectDependencies( project.getArtifacts(),
-                    project.getDependencyArtifacts() );
+                    MojoHelper.getDependencyArtifacts( project ) );
         }
         return dependencyArtifacts;
     }
@@ -442,7 +443,7 @@ void initFromMojo( AggregatorAddThirdPartyMojo mojo, MavenProject mavenProject,
         resolvedOverrideUrl  = mojo.resolvedOverrideUrl;
         missingLicensesFileArtifact = mojo.missingLicensesFileArtifact;
         localRepository = mojo.localRepository;
-        dependencies = new HashSet<>( mavenProject.getDependencyArtifacts() );
+        dependencies = new HashSet<>( MojoHelper.getDependencyArtifacts( mavenProject ) );
         licenseMerges = mojo.licenseMerges;
         licenseMergesFile = mojo.licenseMergesFile;
         includedLicenses = mojo.includedLicenses;

src/main/java/org/codehaus/mojo/license/AggregateDownloadLicensesMojo.java

@@ -29,6 +29,7 @@
 import org.apache.maven.project.MavenProject;
 import org.codehaus.mojo.license.api.ResolvedProjectDependencies;
 import org.codehaus.mojo.license.download.LicensedArtifact;
+import org.codehaus.mojo.license.utils.MojoHelper;
 
 import java.util.List;
 import java.util.Map;
@@ -115,8 +116,7 @@ protected Map<String, LicensedArtifact> getDependencies()
         for ( MavenProject p : reactorProjects )
         {
             licensedArtifactResolver.loadProjectDependencies( new ResolvedProjectDependencies( p.getArtifacts(),
-                                                                                       p.getDependencyArtifacts() ),
-                                                      this, remoteRepositories, result );
+                    MojoHelper.getDependencyArtifacts( p ) ), this, remoteRepositories, result );
         }
         return result;
     }

src/main/java/org/codehaus/mojo/license/DownloadLicensesMojo.java

@@ -31,6 +31,7 @@
 import org.apache.maven.plugins.annotations.ResolutionScope;
 import org.codehaus.mojo.license.api.ResolvedProjectDependencies;
 import org.codehaus.mojo.license.download.LicensedArtifact;
+import org.codehaus.mojo.license.utils.MojoHelper;
 
 /**
  * Download the license files of all the current project's dependencies, and generate a summary file containing a list
@@ -86,7 +87,7 @@ protected Map<String, LicensedArtifact> getDependencies()
     {
         final Map<String, LicensedArtifact> result = new TreeMap<>();
         licensedArtifactResolver.loadProjectDependencies(
-                new ResolvedProjectDependencies( project.getArtifacts(), project.getDependencyArtifacts() ),
+                new ResolvedProjectDependencies( project.getArtifacts(), MojoHelper.getDependencyArtifacts( project ) ),
                 this, remoteRepositories, result );
         return result;
     }

src/main/java/org/codehaus/mojo/license/LicensesXmlInsertVersionsMojo.java

@@ -42,6 +42,7 @@
 import org.codehaus.mojo.license.download.LicensedArtifact;
 import org.codehaus.mojo.license.download.ProjectLicenseInfo;
 import org.codehaus.mojo.license.utils.FileUtil;
+import org.codehaus.mojo.license.utils.MojoHelper;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -139,9 +140,8 @@ public ArtifactFilters getArtifactFilters()
                 }
             };
             final Map<String, LicensedArtifact> resolvedDeps = new TreeMap<String, LicensedArtifact>();
-            licensedArtifactResolver.loadProjectDependencies(
-                    new ResolvedProjectDependencies( project.getArtifacts(), project.getDependencyArtifacts() ),
-                                                     config, remoteRepositories, resolvedDeps );
+            licensedArtifactResolver.loadProjectDependencies( new ResolvedProjectDependencies( project.getArtifacts(),
+                    MojoHelper.getDependencyArtifacts( project ) ), config, remoteRepositories, resolvedDeps );
             final Map<String, LicensedArtifact> resolvedDepsMap = new HashMap<>( resolvedDeps.size() );
             for ( LicensedArtifact dep : resolvedDeps.values() )
             {

src/main/java/org/codehaus/mojo/license/utils/MojoHelper.java

@@ -25,14 +25,18 @@
 import org.apache.maven.artifact.Artifact;
 import org.apache.maven.model.Resource;
 import org.apache.maven.project.MavenProject;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.io.File;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.text.MessageFormat;
 import java.util.Arrays;
 import java.util.Comparator;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 /**
  * Mojo helper methods.
@@ -42,6 +46,7 @@
  */
 public class MojoHelper
 {
+    private static final Logger LOG = LoggerFactory.getLogger( MojoHelper.class );
 
     /**
      * Add the directory as a resource of the given project.
@@ -245,4 +250,27 @@ public static List<String> getParams( String params )
         String[] split = params == null ? new String[0] : params.split( "," );
         return Arrays.asList( split );
     }
+
+    /**
+     * {@link MavenProject#getDependencyArtifacts()} is deprecated.
+     *
+     * <p>
+     * This method checks if the dependency artifacts is {@code null} and returns an empty {@code HashSet} to avoid the
+     * {@code NullPointerException}s caused by the {@link MavenProject#getDependencyArtifacts()} returning {@code null}.
+     * </p>
+     *
+     * @param project the MavenProject to retrieve artifacts from
+     * @return a HashSet of dependencies or an empty set
+     */
+    public static Set<Artifact> getDependencyArtifacts( MavenProject project )
+    {
+        if ( project == null || project.getDependencyArtifacts() == null )
+        {
+            LOG.warn( "" );
+            LOG.warn( "Non-transitive dependencies cannot be found. " );
+            LOG.warn( "" );
+            return new HashSet<Artifact>();
+        }
+        return project.getDependencyArtifacts();
+    }
 }