Maven is 3.1.0.
I'm using versions-maven-plugin:2.2 in my project's pom.xml (as shown below). Apart from the usual pom.xml file configuration, I'm just showing the main code snapshot below:
<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>
<artifactId>tools-parent</artifactId>
<version>0.0.7-SNAPSHOT</version>
<packaging>pom</packaging>
<description>
Infrastructure related to the "vapp" and
"deployer" utilities.
</description>
<parent>
<groupId>com.company.product</groupId>
<artifactId>deploy-parent</artifactId>
<version>0.0.6-SNAPSHOT</version>
</parent>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-scm-plugin</artifactId>
<version>1.9.4</version>
<configuration>
<connectionType>connection</connectionType>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>versions-maven-plugin</artifactId>
<version>2.2</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-enforcer-plugin</artifactId>
<version>1.4</version>
<executions>
<execution>
<!-- Make sure that only non-snapshot versions are used for the dependencies. Only active when property 'snapshotDependencyAllowed' is false. -->
<id>enforce-no-snapshots</id>
<goals>
<goal>enforce</goal>
</goals>
<configuration>
<skip>${snapshotDependencyAllowed}</skip>
<rules>
<requireReleaseDeps>
<message>No Snapshots Allowed!</message>
</requireReleaseDeps>
<requireReleaseVersion>
<message>No Snapshots Allowed!</message>
</requireReleaseVersion>
</rules>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
Now, when I run: mvn clean install, it builds successfully.
NOTE: In my project, I have a parent section, where I'm dependent upon deploy-parent artifact whose group id "com.company.product" is the same group id what I want to tools-parent artifact (whose pom.xml I have pasted above) but deploy-parent is an artifact of another repository/project.
When I run: mvn versions:set -DnewVersion=0.0.7, I get the following error message.
[INFO] ------------------------------------------------------------------------
[INFO] Building tools-parent 0.0.7-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- versions-maven-plugin:2.2:set (default-cli) @ tools-parent ---
[INFO] Searching for local aggregator root...
[INFO] Local aggregation root: /user/home/u100123/giga/tools
[INFO] Processing change of com.company.product:tools-parent:0.0.7-SNAPSHOT -> 0.0.7
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] tools-parent .................................... FAILURE [1.093s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.404s
[INFO] Finished at: Fri May 01 20:44:22 GMT-00:00 2015
[INFO] Final Memory: 12M/246M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:versions-maven-plugin:2.2:set (default-cli) on project tools-parent: Execution default-cli of goal org.codehaus.mojo:versions-maven-plugin:2.2:set failed. NullPointerException -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginExecutionException
NOW, when I change the versions-maven-plugin version back to 2.1 (which what I was using earlier), the above mvn versions:set -DnewVersion=0.0.7 command is working successfully and pom.xml file is successfully getting changed to <version>0.0.7</version> for tools-parent artifact.
With version 2.2, it's giving me the error and not changing the version to 0.0.7.
It seems like some bug.
Solution:
1. I have to add <groupId>com.company.product</groupId> property outside of ... section as well i.e. for tools-parent, NOW version-maven-plugin:2.2 is working fine i.e. I added the top line (as shown below). The only thing is, what's the use of parent section then (apart from inheriting the main code of what deploy-parent is brining to tools-parent project). Why groupId needs to be defined output of parent section for artifactId tools-parent when it's already there in the parent section for versions-maven-plugin:2.2 to work successfully.
The most important thing is: This issue occurs only in case your pom.xml for a project/module has a <parent> section where the parent section's artifactId is not the parent of the project itself (a typical - Maven Uncle situation) i.e. if tools-parent artifact is defined in the parent section of another module (lets say tools-child) then version 2.2 will work successfully. But if tools-child's parent section is not containing the artifactId as "tools-parent" and is something else for ex: deploy-parent/some-different-project-artifact (which resides in a different project in your source control tool) then, for tools-child artifactId, we need groupId value also set outside of the parent section as well (even if the groupId of parent section's artifactId is same/different to tools-child's groupId).
<groupId>com.company.product</groupId>
<artifactId>tools-parent</artifactId>
<version>0.0.7-SNAPSHOT</version>
<packaging>pom</packaging>
<description>
Infrastructure related to the "vapp" and
"deployer" utilities.
</description>
<parent>
<groupId>com.company.product</groupId>
<artifactId>deploy-parent</artifactId>
<version>0.0.6-SNAPSHOT</version>
</parent>
--OR
2. Switch back to versions-maven-plugin:2.1