A mavenized Grails project has 2 competing sources stating the version of the application

1. <version> within pom.xml
2. app.version within application.properties

If 2. does not match 1. the grails-maven-plugin will abort the build, urging you to manually fix the version mismatch. Although somewhat clumsy, the release will still succeed if you edit application.properties and re-start the failing mvn release:prepare. However, you’re somewhat stuck, if the release is to be performed from within a continous integration server (e.g. Hudson).

Thus I devised a work-around, that will compare both versions and update the version within application.properties if required. My work-around is far from perfect, as I was unable to integrate it within the Maven lifecycle defined by the grails-maven-plugin. This lifecycle will always and unconditionally bind its own code to the validate phase first (aborting on version mismatches). Therefore I resorted to binding my repair action to the clean phase and changed the goals of the maven-release-plugin to perform a clean before invoking the deploy. Note that this will produce a consistent war (both pom and application.properties set to the release version), but will not resolve the discrepancy within the tagged sources (i.e. application.properties will still state the snapshot version).

Here’s my code. It uses a profile, which is only activated, if the file application.properties is actually present. Thus the code can be included within a parent pom.xml that might be used with non-Grails projects as well:

<profiles>
 <profile>
  <id>enable-reset.application.properties</id>
  <activation>
   <activeByDefault>false</activeByDefault>
   <file>
    <exists>application.properties</exists>
   </file>
  </activation>
  <build>
   <pluginManagement>
    <plugins>
     <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-release-plugin</artifactId>
      <configuration>
       <!-- invoke clean first - see below -->
       <goals>clean deploy</goals>
      </configuration>
     </plugin>
    </plugins>
   </pluginManagement>

   <plugins>
    <!--
     Allow release:prepare/perform to succeed with Grails
     app. Reset application.properties.app.version to
     project.version Sorta hack on clean, as
     grails-maven-plugin:validate ALWAYS runs first and
     connot be preceeded by any other execution
    -->
    <plugin>
     <artifactId>maven-antrun-plugin</artifactId>
     <version>1.3</version>
     <executions>
      <execution>
       <id>reset.application.properties</id>
       <phase>clean</phase>
       <goals>
        <goal>run</goal>
       </goals>
       <configuration>
        <tasks>
         <taskdef resource="net/sf/antcontrib/antlib.xml"
          classpathref="maven.plugin.classpath" />
         <if>
          <available file="application.properties" />
          <then>
           <property file="application.properties"
            prefix="application.properties" />
           <if>
            <not>
             <equals arg1="${project.version}"
              arg2="${application.properties.app.version}" />
            </not>
            <then>
             <propertyfile file="application.properties"
              comment="Grails Metadata file">
              <entry operation="=" type="string" key="app.version"
               value="${project.version}" />
             </propertyfile>
            </then>
           </if>
          </then>
         </if>
        </tasks>
       </configuration>
      </execution>
     </executions>

     <dependencies>
      <dependency>
       <groupId>org.apache.ant</groupId>
       <artifactId>ant</artifactId>
       <version>1.7.1</version>
      </dependency>
      <dependency>
       <groupId>org.apache.ant</groupId>
       <artifactId>ant-nodeps</artifactId>
       <version>1.7.1</version>
      </dependency>
      <dependency>
       <groupId>ant-contrib</groupId>
       <artifactId>ant-contrib</artifactId>
       <version>1.0b3</version>
       <exclusions>
        <exclusion>
         <groupId>ant</groupId>
         <artifactId>ant</artifactId>
        </exclusion>
       </exclusions>
      </dependency>
     </dependencies>
    </plugin>
   </plugins>
  </build>
 </profile>
</profiles>

Links:

• GRAILS-5859 – maven release:prepare fails because of version not changed in application.properties
• Grails User – maven release fails because of app.version
• Hudson – M2 Release Plugin