throw MojoExecutionException when artifact has no file in PropertiesMojo

src/main/java/org/apache/maven/plugins/dependency/PropertiesMojo.java

@@ -20,6 +20,7 @@
 
 import javax.inject.Inject;
 
+import java.io.File;
 import java.util.List;
 import java.util.Set;
 
@@ -112,10 +113,13 @@ public void execute() throws MojoExecutionException {
         Set<Artifact> artifacts = project.getArtifacts();
 
         for (Artifact artifact : artifacts) {
-            project.getProperties()
-                    .setProperty(
-                            artifact.getDependencyConflictId(),
-                            artifact.getFile().getAbsolutePath());
+            String conflictId = artifact.getDependencyConflictId();
+            File file = artifact.getFile();
+            if (file == null) {
+                getLog().warn("Artifact " + conflictId + " has no associated file; no property will be set for it.");
+                continue;
+            }
+            project.getProperties().setProperty(conflictId, file.getAbsolutePath());
         }
 
         if (extraArtifacts != null) {
@@ -130,10 +134,14 @@ public void execute() throws MojoExecutionException {
                             resolverUtil.createArtifactFromParams(paramArtifact);
                     artifact = resolverUtil.resolveArtifact(artifact, project.getRemoteProjectRepositories());
 
-                    this.project
-                            .getProperties()
-                            .setProperty(
-                                    toConflictId(artifact), artifact.getFile().getAbsolutePath());
+                    String conflictId = toConflictId(artifact);
+                    File file = artifact.getFile();
+                    if (file == null) {
+                        getLog().warn("Extra artifact " + conflictId
+                                + " has no associated file; no property will be set for it.");
+                        continue;
+                    }
+                    this.project.getProperties().setProperty(conflictId, file.getAbsolutePath());
                 }
             } catch (ArtifactResolutionException | ArtifactDescriptorException e) {
                 throw new MojoExecutionException("Couldn't download artifact: " + e.getMessage(), e);

src/test/java/org/apache/maven/plugins/dependency/TestPropertiesMojo.java

@@ -35,6 +35,7 @@
 import org.junit.jupiter.api.Test;
 import org.mockito.Mockito;
 
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.Mockito.when;
 
@@ -102,4 +103,17 @@ void testSetPropertiesForExtractArtifacts(PropertiesMojo mojo) throws Exception
         assertTrue(project.getProperties().containsKey(depId2));
         assertTrue(new File(project.getProperties().getProperty(depId1)).exists());
     }
+
+    @Test
+    @InjectMojo(goal = "properties")
+    void testNullFileSkipsProperty(PropertiesMojo mojo) throws Exception {
+        Artifact artifact = Mockito.mock(Artifact.class);
+        when(artifact.getDependencyConflictId()).thenReturn("group:artifact");
+        when(artifact.getFile()).thenReturn(null);
+        when(this.project.getArtifacts()).thenReturn(new HashSet<>(Arrays.asList(artifact)));
+
+        mojo.execute();
+
+        assertFalse(project.getProperties().containsKey("group:artifact"));
+    }
 }