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Checking for new plugin updates

The display-plugin-updates goal will check all the plugins and reports used in your project and display a list of those plugins with newer versions available, first staying with the same Maven version prerequisite, then additional options if you update the Maven version prerequisite.

Here are some examples of what this looks like:

svn checkout http://svn.codehaus.org/mojo/trunk/mojo/build-helper-maven-plugin build-helper-maven-plugin
cd build-helper-maven-plugin
mvn versions:display-plugin-updates

Which produces the following output:

[INFO] ------------------------------------------------------------------------
[INFO] Building Build Helper Maven Plugin
[INFO]    task-segment: [versions:display-plugin-updates]
[INFO] ------------------------------------------------------------------------
[INFO] [versions:display-plugin-updates]
[INFO]
[INFO] The following plugin updates are available:
[INFO]   maven-checkstyle-plugin .................................. 2.6 -> 2.8
[INFO]   maven-deploy-plugin ...................................... 2.5 -> 2.7
[INFO]   maven-jar-plugin ..................................... 2.3.1 -> 2.3.2
[INFO]   maven-plugin-plugin ...................................... 2.7 -> 2.9
[INFO]   maven-resources-plugin ................................. 2.4.3 -> 2.5
[INFO]   maven-site-plugin ..................... ${sitePluginVersion} -> 2.0.1
[INFO]
[INFO] All plugins have a version specified.
[INFO]
[INFO] Project defines minimum Maven version as: 2.0.6
[INFO] Plugins require minimum Maven version of: 2.2.1
[INFO]
[WARNING] Project (which is a Maven plugin) targets Maven 2.0.6 or newer
[WARNING] but requires Maven 2.2.1 or newer to build.
[WARNING] This may or may not be a problem. A Maven Enforcer rule can help
[WARNING] enforce that the correct version of Maven is used to build this plugin.
[INFO]
[INFO] Require Maven 2.0.9 to use the following plugin updates:
[INFO]   maven-compiler-plugin ......................................... 2.3.2
[INFO]   maven-surefire-plugin .......................................... 2.10
[INFO]
[INFO] Require Maven 2.1.0 to use the following plugin updates:
[INFO]   maven-site-plugin ..................... ${sitePluginVersion} -> 2.1.1
[INFO]
[INFO] Require Maven 2.2.0 to use the following plugin updates:
[INFO]   maven-site-plugin ....................... ${sitePluginVersion} -> 3.0
[INFO]
[INFO] Require Maven 2.2.1 to use the following plugin updates:
[INFO]   maven-changes-plugin ............................................ 2.5
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 6 seconds
[INFO] Finished at: Wed Nov 30 21:59:36 GMT 2011
[INFO] Final Memory: 21M/81M
[INFO] ------------------------------------------------------------------------

The plugin will also warn if you have not specified the versions of any plugins that you are using and tell you what version you are currently using. Best practice in Maven is to always specify the plugin versions in order to ensure that builds are reproducible.

For example the following pom.xml:

<project>
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.codehaus.mojo.versions-maven-plugin.it</groupId>
  <artifactId>parent</artifactId>
  <version>2.0</version>
  <packaging>pom</packaging>

  <build>
    <pluginManagement>
      <plugins>
        <plugin>
          <artifactId>maven-checkstyle-plugin</artifactId>
          <version>2.1</version>
        </plugin>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-javadoc-plugin</artifactId>
        </plugin>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-compiler-plugin</artifactId>
          <configuration>
            <source>1.4</source>
            <target>1.4</target>
          </configuration>
        </plugin>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>build-helper-maven-plugin</artifactId>
      </plugin>
      </plugins>
    </pluginManagement>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-clean-plugin</artifactId>
        <version>2.1</version>
      </plugin>
    </plugins>
  </build>
</project>

produces the following output (when run using Maven 2.0.6):

[INFO] ----------------------------------------------------------------------------
[INFO] Building Unnamed - org.codehaus.mojo.versions-maven-plugin.it:parent:pom:2.0
[INFO]    task-segment: [versions:display-plugin-updates]
[INFO] ----------------------------------------------------------------------------
[INFO] [versions:display-plugin-updates]
[INFO]
[INFO] The following plugin updates are available:
[INFO]   maven-clean-plugin ....................................... 2.1 -> 2.2
[INFO]
[WARNING] The following plugins do not have their version specified:
[WARNING]   maven-compiler-plugin ...................................... 2.0.2
[WARNING]   maven-deploy-plugin .......................................... 2.4
[WARNING]   maven-install-plugin ......................................... 2.2
[WARNING]   maven-javadoc-plugin ......................................... 2.0
[WARNING]   maven-site-plugin ..................................... 2.0-beta-4
[WARNING]   org.codehaus.mojo:build-helper-maven-plugin .................. 1.0
[INFO]
[WARNING] Project does not define minimum Maven version, default is: 2.0
[INFO] Plugins require minimum Maven version of: 2.0.6
[INFO]
[ERROR] Project does not define required minimum version of Maven.
[ERROR] Update the pom.xml to contain
[ERROR]     <prerequisites>
[ERROR]       <maven>2.0.6</maven>
[ERROR]     </prerequisites>
[INFO]
[INFO] Require Maven 2.0.2 to use the following plugin updates:
[INFO]   maven-checkstyle-plugin ......................................... 2.1
[INFO]   maven-javadoc-plugin ..................................... 2.0 -> 2.2
[INFO]   maven-site-plugin .......................... 2.0-beta-4 -> 2.0-beta-7
[INFO]   org.codehaus.mojo:build-helper-maven-plugin .............. 1.0 -> 1.5
[INFO]
[INFO] Require Maven 2.0.6 to use the following plugin updates:
[INFO]   maven-checkstyle-plugin .................................. 2.1 -> 2.8
[INFO]   maven-clean-plugin ..................................... 2.1 -> 2.4.1
[INFO]   maven-deploy-plugin ...................................... 2.4 -> 2.7
[INFO]   maven-install-plugin ................................... 2.2 -> 2.3.1
[INFO]   maven-javadoc-plugin ..................................... 2.0 -> 2.3
[INFO]   maven-site-plugin ............................... 2.0-beta-4 -> 2.0.1
[INFO]   org.codehaus.mojo:build-helper-maven-plugin .............. 1.0 -> 1.7
[INFO]   org.codehaus.mojo:versions-maven-plugin ......................... 1.2
[INFO]
[INFO] Require Maven 2.0.8 to use the following plugin updates:
[INFO]   maven-javadoc-plugin ..................................... 2.0 -> 2.4
[INFO]
[INFO] Require Maven 2.0.9 to use the following plugin updates:
[INFO]   maven-compiler-plugin ......................................... 2.3.2
[INFO]   maven-javadoc-plugin ..................................... 2.0 -> 2.8
[INFO]
[INFO] Require Maven 2.1.0 to use the following plugin updates:
[INFO]   maven-site-plugin ............................... 2.0-beta-4 -> 2.1.1
[INFO]
[INFO] Require Maven 2.2.0 to use the following plugin updates:
[INFO]   maven-site-plugin ................................. 2.0-beta-4 -> 3.0
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3 seconds
[INFO] Finished at: Wed Nov 30 22:02:14 GMT 2011
[INFO] Final Memory: 26M/81M
[INFO] ------------------------------------------------------------------------

Note: that because the POM does not specify versions for some plugins, Maven defaults to using the latest compatible version (Maven 3 complains about the version not being specified), and hence the reported minimum required Maven version tends to be the same as the version of Maven that is running the mojo

When run with Maven 2.0.9 (which defines versions of core plugins in the super-pom, and removes some plugin from the lifecycle for the pom lifecycle), we get the following output:

[INFO] ------------------------------------------------------------------------
[INFO] Building Unnamed - org.codehaus.mojo.versions-maven-plugin.it:parent:pom:2.0
[INFO]    task-segment: [versions:display-plugin-updates]
[INFO] ------------------------------------------------------------------------
[INFO] [versions:display-plugin-updates]
[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]   maven-deploy-plugin ......................... (from super-pom) 2.4
[WARNING]   maven-install-plugin ........................ (from super-pom) 2.2
[WARNING]   maven-site-plugin .................... (from super-pom) 2.0-beta-4
[WARNING]   org.codehaus.mojo:build-helper-maven-plugin .................. 1.0
[INFO]
[WARNING] Project does not define minimum Maven version, default is: 2.0
[INFO] Plugins require minimum Maven version of: 2.0.6
[INFO]
[ERROR] Project does not define required minimum version of Maven.
[ERROR] Update the pom.xml to contain
[ERROR]     <prerequisites>
[ERROR]       <maven>2.0.6</maven>
[ERROR]     </prerequisites>
[INFO]
[INFO] Require Maven 2.0.2 to use the following plugin updates:
[INFO]   maven-checkstyle-plugin ......................................... 2.1
[INFO]   maven-site-plugin .......................... 2.0-beta-4 -> 2.0-beta-7
[INFO]   org.codehaus.mojo:build-helper-maven-plugin .............. 1.0 -> 1.5
[INFO]
[INFO] Require Maven 2.0.6 to use the following plugin updates:
[INFO]   maven-checkstyle-plugin .................................. 2.1 -> 2.8
[INFO]   maven-clean-plugin ..................................... 2.3 -> 2.4.1
[INFO]   maven-deploy-plugin ...................................... 2.4 -> 2.7
[INFO]   maven-install-plugin ................................... 2.2 -> 2.3.1
[INFO]   maven-site-plugin ............................... 2.0-beta-4 -> 2.0.1
[INFO]   org.codehaus.mojo:build-helper-maven-plugin .............. 1.0 -> 1.7
[INFO]   org.codehaus.mojo:versions-maven-plugin ......................... 1.2
[INFO]
[INFO] Require Maven 2.1.0 to use the following plugin updates:
[INFO]   maven-site-plugin ............................... 2.0-beta-4 -> 2.1.1
[INFO]
[INFO] Require Maven 2.2.0 to use the following plugin updates:
[INFO]   maven-site-plugin ................................. 2.0-beta-4 -> 3.0
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 5 seconds
[INFO] Finished at: Wed Nov 30 22:09:59 GMT 2011
[INFO] Final Memory: 20M/81M
[INFO] ------------------------------------------------------------------------

And the following POM:

<project>
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>org.codehaus.mojo.versions-maven-plugin.it</groupId>
    <artifactId>parent</artifactId>
    <version>2.0</version>
    <relativePath>../parent-2.0/pom.xml</relativePath>
  </parent>

  <artifactId>child</artifactId>
  <packaging>jar</packaging>

  <prerequisites>
    <maven>2.0.2</maven>
  </prerequisites>

  <build>
    <pluginManagement>
      <plugins>
        <plugin>
          <artifactId>maven-checkstyle-plugin</artifactId>
          <version>2.0</version>
        </plugin>
      </plugins>
    </pluginManagement>
    <plugins>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>build-helper-maven-plugin</artifactId>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-clean-plugin</artifactId>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-javadoc-plugin</artifactId>
      </plugin>
    </plugins>
  </build>

</project>

produces the following output:

[INFO] ------------------------------------------------------------------------
[INFO] Building Unnamed - org.codehaus.mojo.versions-maven-plugin.it:child:pom:2.0
[INFO]    task-segment: [versions:display-plugin-updates]
[INFO] ------------------------------------------------------------------------
[INFO] [versions:display-plugin-updates]
[INFO]
[INFO] The following plugin updates are available:
[INFO]   maven-checkstyle-plugin .................................. 2.0 -> 2.8
[INFO]   maven-clean-plugin ..................................... 2.1 -> 2.4.1
[INFO]
[WARNING] The following plugins do not have their version specified:
[WARNING]   org.codehaus.mojo:build-helper-maven-plugin .................. 1.7
[INFO]
[INFO] Project defines minimum Maven version as: 2.0.8
[INFO] Plugins require minimum Maven version of: 2.0.8
[INFO]
[INFO] No plugins require a newer version of Maven than specified by the pom.
[INFO]
[INFO] Require Maven 2.0.9 to use the following plugin updates:
[INFO]   maven-javadoc-plugin .................................... 2.7 ->  2.8
[INFO]
[INFO] Require Maven 2.1.0 to use the following plugin updates:
[INFO]   maven-site-plugin ...................................... 2.0 -> 2.1.1
[INFO]
[INFO] Require Maven 2.2.0 to use the following plugin updates:
[INFO]   maven-site-plugin ........................................ 2.0 -> 3.0
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4 seconds
[INFO] Finished at: Fri Nov 25 18:28:34 GMT 2011
[INFO] Final Memory: 17M/81M
[INFO] ------------------------------------------------------------------------