Maven ignoring plugin version from pluginManagement in profile of submodule - maven

Question

I'm defining plugin versions in the <pluginManagement> section of a parent POM and want to use them in the <plugins> section of submodules.
This is working, unless the plugin is being used inside a profile of a submodule. In this case, the version from the parent POM's <pluginManagement> section is ignored.
Output of mvn -v:
Apache Maven 3.3.9 (bb52d8502b132ec0a5a3f4c09453c07478323dc5; 2015-11-10T17:41:47+01:00)
Maven home: /usr/local/Cellar/maven/3.3.9/libexec
Java version: 1.8.0_102, vendor: Oracle Corporation
Java home: /Library/Java/JavaVirtualMachines/jdk1.8.0_102.jdk/Contents/Home/jre
Default locale: de_DE, platform encoding: UTF-8
OS name: "mac os x", version: "10.11.6", arch: "x86_64", family: "mac"
./pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<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>
<prerequisites>
<maven>3.1.0</maven>
</prerequisites>
<modules>
<module>project1</module>
</modules>
<groupId>org.example.test</groupId>
<artifactId>test-parent</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>pom</packaging>
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>com.github.eirslett</groupId>
<artifactId>frontend-maven-plugin</artifactId>
<version>1.0</version>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
./project1/pom.xml:
<?xml version="1.0" encoding="UTF-8"?>
<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>
<prerequisites>
<maven>3.1.0</maven>
</prerequisites>
<parent>
<groupId>org.example.test</groupId>
<artifactId>test-parent</artifactId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<artifactId>project1</artifactId>
<profiles>
<profile>
<id>p1</id>
<build>
<plugins>
<plugin>
<groupId>com.github.eirslett</groupId>
<artifactId>frontend-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</profile>
</profiles>
</project>
Output of mvn versions:display-plugin-updates:
$ mvn versions:display-plugin-updates
[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Build Order:
[INFO]
[INFO] test-parent
[INFO] project1
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building test-parent 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- versions-maven-plugin:2.2:display-plugin-updates (default-cli) # test-parent ---
[INFO]
[INFO] All plugins with a version specified are using the latest versions.
[INFO]
[INFO] Project defines minimum Maven version as: 3.1.0
[INFO] Plugins require minimum Maven version of: 3.1.0
[INFO] Note: the super-pom from Maven 3.3.9 defines some of the plugin
[INFO] versions and may be influencing the plugins required minimum Maven
[INFO] version.
[INFO]
[INFO] No plugins require a newer version of Maven than specified by the pom.
[INFO]
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building project1 1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- versions-maven-plugin:2.2:display-plugin-updates (default-cli) # project1 ---
[INFO]
[INFO] All plugins with a version specified are using the latest versions.
[INFO]
[WARNING] The following plugins do not have their version specified:
[WARNING] com.github.eirslett:frontend-maven-plugin ................. 0.0.26
[INFO]
[INFO] Project defines minimum Maven version as: 3.1.0
[INFO] Plugins require minimum Maven version of: 3.1.0
[INFO] Note: the super-pom from Maven 3.3.9 defines some of the plugin
[INFO] versions and may be influencing the plugins required minimum Maven
[INFO] version.
[INFO]
[INFO] No plugins require a newer version of Maven than specified by the pom.
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] test-parent ........................................ SUCCESS [ 0.851 s]
[INFO] project1 ........................................... SUCCESS [ 0.314 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.649 s
[INFO] Finished at: 2016-09-16T16:03:04+02:00
[INFO] Final Memory: 13M/247M
[INFO] ------------------------------------------------------------------------
I can duplicate the information from the <pluginManagement> section of the parent POM inside the submodules to make it work, but I want to avoid this for obvious reasons.

Answer 1

Maven is not ignoring it, you can check it by executing the following:
mvn -pl project1 help:effective-pom -Doutput=noProfilePom.xml
The effective-pom goal will:
Displays the effective POM as an XML for this build, with the active profiles factored in.
Checking the noProfilePom.xml generated, you will see what effectively Maven will run when building the pom.xml of the project1 module.
There we can see:
<pluginManagement>
<plugins>
...
<plugin>
<groupId>com.github.eirslett</groupId>
<artifactId>frontend-maven-plugin</artifactId>
<version>1.0</version>
</plugin>
</plugins>
</pluginManagement>
<plugins>
...
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>2.5</version>
<executions>
<execution>
<id>default-clean</id>
<phase>clean</phase>
<goals>
<goal>clean</goal>
</goals>
</execution>
</executions>
</plugin>
...
</plugins>
Hence, the pluginManagement has been merged properly (taken from the parent), while the plugins section doesn't provide it.
But running the following:
mvn -pl project1 -Pp1 help:effective-pom -Doutput=withProfilePom.xml
Note: we are also activating the profile via -Pp1 as part of the goal execution.
As part of the generated withProfilePom.xml will have:
<pluginManagement>
<plugins>
...
<plugin>
<groupId>com.github.eirslett</groupId>
<artifactId>frontend-maven-plugin</artifactId>
<version>1.0</version>
</plugin>
</plugins>
</pluginManagement>
<plugins>
<plugin>
<groupId>com.github.eirslett</groupId>
<artifactId>frontend-maven-plugin</artifactId>
<version>1.0</version>
</plugin>
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>2.5</version>
<executions>
<execution>
<id>default-clean</id>
<phase>clean</phase>
<goals>
<goal>clean</goal>
</goals>
</execution>
</executions>
</plugin>
...
</plugins>
This time the p1 profile was active and its has properly injected into the plugins section its plugin declaration, taking then its version from the pluginManagement of the parent.
Hence: the pluginManagement section is not ignored by plugins declared in a profile.