Fixed mojohaus#1184: Filtering out the extensions reported as plugins…

… by Maven

versions-maven-plugin/src/it/it-display-plugin-updates-issue-1184-01/invoker.properties

@@ -0,0 +1,2 @@
+invoker.goals = ${project.groupId}:${project.artifactId}:${project.version}:display-plugin-updates
+invoker.mavenOpts = -Dversions.outputFile=./output.txt -DoutputEncoding=UTF-8

versions-maven-plugin/src/it/it-display-plugin-updates-issue-1184-01/pom.xml

@@ -0,0 +1,21 @@
+<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>localhost</groupId>
+  <artifactId>it-display-extension-updates-002</artifactId>
+
+  <version>1.0</version>
+  <packaging>pom</packaging>
+
+  <build>
+    <extensions>
+      <extension>
+        <groupId>localhost</groupId>
+        <artifactId>dummy-api</artifactId>
+        <version>1.0</version>
+      </extension>
+    </extensions>
+  </build>
+
+</project>

versions-maven-plugin/src/it/it-display-plugin-updates-issue-1184-01/verify.groovy

@@ -0,0 +1,3 @@
+def output = new File( basedir, "output.txt").text
+assert !(output =~ /\Qlocalhost:dummy-api\E\s*\.*\s*\Q1.0\E/)
+

versions-maven-plugin/src/it/it-display-plugin-updates-issue-1184/.mvn/extensions.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<extensions xmlns="http://maven.apache.org/EXTENSIONS/1.1.0"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xsi:schemaLocation="http://maven.apache.org/EXTENSIONS/1.1.0 https://maven.apache.org/xsd/core-extensions-1.1.0.xsd">
+  <extension>
+    <groupId>localhost</groupId>
+    <artifactId>dummy-api</artifactId>
+    <version>1.0</version>
+  </extension>
+</extensions>

versions-maven-plugin/src/it/it-display-plugin-updates-issue-1184/invoker.properties

@@ -0,0 +1,2 @@
+invoker.goals = ${project.groupId}:${project.artifactId}:${project.version}:display-plugin-updates
+invoker.mavenOpts = -Dversions.outputFile=./output.txt -DoutputEncoding=UTF-8

versions-maven-plugin/src/it/it-display-plugin-updates-issue-1184/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>
+  <groupId>localhost</groupId>
+  <artifactId>it-display-extension-updates-002</artifactId>
+
+  <version>1.0</version>
+  <packaging>pom</packaging>
+
+</project>

versions-maven-plugin/src/it/it-display-plugin-updates-issue-1184/verify.groovy

@@ -0,0 +1,3 @@
+def output = new File( basedir, "output.txt").text
+assert !(output =~ /\Qlocalhost:dummy-api\E\s*\.*\s*\Q1.0\E/)
+

versions-maven-plugin/src/main/java/org/codehaus/mojo/versions/DisplayPluginUpdatesMojo.java

@@ -1002,6 +1002,8 @@ private static Stream<Plugin> getPluginManagementPlugins(BuildBase buildBase) {
 
     private static Stream<Plugin> getBuildPlugins(BuildBase buildBase, Map<String, String> parentPluginManagement) {
         return buildBase.getPlugins().stream()
+                // apparently, core and build extensions are seen as plugins with a null goal, so let's filter them out
+                .filter(plugin -> plugin.getGoals() != null)
                 // removing plugins without a version
                 // and with the parent also not defining it for them
                 .filter(plugin -> plugin.getVersion() != null || parentPluginManagement.get(plugin.getKey()) == null);