yuicompressor plugin execution not covered in m2e

Question

After a long search for a JavaScript compressor I could use in Maven, I finally found one:

        <plugin>
            <groupId>net.alchim31.maven</groupId>
            <artifactId>yuicompressor-maven-plugin</artifactId>
            <version>1.1</version>
            <executions>
                <execution>
                    <goals>
                        <goal>compress</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <jswarn>false</jswarn>
            </configuration>
        </plugin>

Now in the latest version of m2e in Eclipse, I get the following error:

Plugin execution not covered by lifecycle configuration: net.alchim31.maven:yuicompressor-maven-plugin:1.1:compress (execution: default, phase: process-resources)

Lovely. I don't get it---it's just a plugin. Why can't m2e simply call any old plugin I have? What's wrong with this one? How do I fix this?

Answer 1

See http://wiki.eclipse.org/M2E_plugin_execution_not_covered

To solve some long-standing issues, m2e 1.0 requires explicit instructions what to do with all Maven plugins bound to "interesting" phases (see M2E interesting lifecycle phases) of project build lifecycle. We call these instructions "project build lifecycle mapping" or simply "lifecycle mapping" because they define how m2e maps information from project pom.xml file to Eclipse workspace project configuration and behaviour during Eclipse workspace build.

Project build lifecycle mapping configuration can be specified in project pom.xml, contributed by Eclipse plugins and there is also default configuration for some commonly used Maven plugins shipped with m2e. We call these "lifecycle mapping metadata sources". m2e will create error marker like below for all plugin executions that do not have lifecycle mapping in any of the mapping metadata sources.

Plugin execution not covered by lifecycle configuration:
org.apache.maven.plugins:maven-antrun-plugin:1.3:run
   (execution: generate-sources-input, phase: generate-sources)

m2e matches plugin executions to actions using combination of plugin groupId, artifactId, version range and goal. There are three basic actions that m2e can be instructed to do with a plugin execution -- ignore, execute and delegate to a project configurator.

Answer 2

If you search around, you'll find a lot of links showing you how to suppress that error. However, I found a way to actually have the default Maven Project Builder execute these plugins within eclipse. The key is to change the <ignore> you find in many suggestions to <execute>. After adding this to my pom, I have automatic aggregation, compression, and deployment off of just a user saving a javascript resource:

<pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.eclipse.m2e</groupId>
                <artifactId>lifecycle-mapping</artifactId>
                <version>1.0.0</version>
                <configuration>
                    <lifecycleMappingMetadata>
                        <pluginExecutions>
                            <pluginExecution>
                                <pluginExecutionFilter>
                                    <groupId>
                                        net.alchim31.maven
                                    </groupId>
                                    <artifactId>
                                        yuicompressor-maven-plugin
                                    </artifactId>
                                    <versionRange>
                                        [1.1,)
                                    </versionRange>
                                    <goals>
                                        <goal>compress</goal>
                                    </goals>
                                </pluginExecutionFilter>
                                <action>
                                    <execute></execute>
                                </action>
                            </pluginExecution>
                        </pluginExecutions>
                    </lifecycleMappingMetadata>
                </configuration>
            </plugin>
        </plugins>
    </pluginManagement>

Answer 3

Maybe you have to provide the id and phase?

<plugin>
    <groupId>net.alchim31.maven</groupId>
    <artifactId>yuicompressor-maven-plugin</artifactId>
    <version>1.1</version>
    <executions>
        <execution>
            <id>compressyui</id>
            <phase>process-resources</phase>
            <goals>
                <goal>compress</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <jswarn>false</jswarn>
    </configuration>
</plugin>

At least i don't get that message with this configuration.