From d7b316a1029eb699ef01d4239271b9cdf291dec8 Mon Sep 17 00:00:00 2001
From: opencode <opencode@example.com>
Date: Wed, 29 Jul 2026 13:23:22 +0000
Subject: [PATCH] [MPH-217] Ensure packaging is always shown in effective-pom
 output

MavenXpp3Writer omits the packaging element when it is null or equals
the default value 'jar'. This leads help:effective-pom to not show
the packaging at all when it is not explicitly set in the POM.

Fix: after serialization, insert the packaging element into the XML
output if missing. This ensures users can always see the effective
packaging value (e.g. jar, pom, war) in the effective POM output.

Includes an integration test with a POM that has no packaging element,
verifying the output contains <packaging>jar</packaging>.
---
 .../invoker.properties                        | 18 ++++++++++++
 .../projects/effective-pom-packaging/pom.xml  | 29 +++++++++++++++++++
 .../effective-pom-packaging/verify.groovy     | 25 ++++++++++++++++
 .../maven/plugins/help/EffectivePomMojo.java  | 10 +++++++
 4 files changed, 82 insertions(+)
 create mode 100644 src/it/projects/effective-pom-packaging/invoker.properties
 create mode 100644 src/it/projects/effective-pom-packaging/pom.xml
 create mode 100644 src/it/projects/effective-pom-packaging/verify.groovy

diff --git a/src/it/projects/effective-pom-packaging/invoker.properties b/src/it/projects/effective-pom-packaging/invoker.properties
new file mode 100644
index 00000000..adecbad1
--- /dev/null
+++ b/src/it/projects/effective-pom-packaging/invoker.properties
@@ -0,0 +1,18 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+invoker.goals = ${project.groupId}:${project.artifactId}:${project.version}:effective-pom
diff --git a/src/it/projects/effective-pom-packaging/pom.xml b/src/it/projects/effective-pom-packaging/pom.xml
new file mode 100644
index 00000000..6622e253
--- /dev/null
+++ b/src/it/projects/effective-pom-packaging/pom.xml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!--
+Licensed to the Apache Software Foundation (ASF) under one
+or more contributor license agreements.  See the NOTICE file
+distributed with this work for additional information
+regarding copyright ownership.  The ASF licenses this file
+to you under the Apache License, Version 2.0 (the
+"License"); you may not use this file except in compliance
+with the License.  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing,
+software distributed under the License is distributed on an
+"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, either express or implied.  See the License for the
+specific language governing permissions and limitations
+under the License.
+-->
+
+<project>
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>org.apache.maven.its.help</groupId>
+  <artifactId>mph-217</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <!-- no packaging set, should default to "jar" -->
+</project>
diff --git a/src/it/projects/effective-pom-packaging/verify.groovy b/src/it/projects/effective-pom-packaging/verify.groovy
new file mode 100644
index 00000000..abb1affa
--- /dev/null
+++ b/src/it/projects/effective-pom-packaging/verify.groovy
@@ -0,0 +1,25 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+def buildLog = new File(basedir, 'build.log');
+assert buildLog.exists()
+
+def LS = System.getProperty("line.separator")
+assert buildLog.text.find(
+        '(?s)' +
+        '  <packaging>jar</packaging>') != null
diff --git a/src/main/java/org/apache/maven/plugins/help/EffectivePomMojo.java b/src/main/java/org/apache/maven/plugins/help/EffectivePomMojo.java
index 4fa115c2..45dbffbc 100644
--- a/src/main/java/org/apache/maven/plugins/help/EffectivePomMojo.java
+++ b/src/main/java/org/apache/maven/plugins/help/EffectivePomMojo.java
@@ -197,6 +197,16 @@ private void writeEffectivePom(MavenProject project, XMLWriter writer) throws Mo
         // This removes the XML declaration written by MavenXpp3Writer
         String effectivePom = prettyFormat(sWriter.toString(), null, true);
 
+        // MavenXpp3Writer omits packaging when it is null or "jar" (the default).
+        // Ensure it is always present so users can see the effective packaging value.
+        if (pom.getPackaging() == null || "jar".equals(pom.getPackaging())) {
+            String packaging = pom.getPackaging() != null ? pom.getPackaging() : project.getPackaging();
+            String packagingTag = "  <packaging>" + packaging + "</packaging>";
+            if (!effectivePom.contains(packagingTag)) {
+                effectivePom = effectivePom.replace("</version>" + LS, "</version>" + LS + packagingTag + LS);
+            }
+        }
+
         writeComment(writer, "Effective POM for project '" + project.getId() + "'");
 
         writer.writeMarkup(effectivePom);